# Amazon VPC and Amazon Aurora
Amazon Virtual Private Cloud (Amazon VPC) makes it possible for you to launch AWS resources, such as Aurora DB clusters, into a virtual private cloud (VPC).
When you use a VPC, you have control over your virtual networking environment. You can choose your own IP address range, create subnets, and configure routing and access control lists. There is no additional cost to run your DB cluster in a VPC.
Accounts have a default VPC. All new DB clusters are created in the default VPC unless you specify otherwise.
**Topics**
+ [
# Working with a DB cluster in a VPC
](USER_VPC.WorkingWithRDSInstanceinaVPC.md)
+ [
# Scenarios for accessing a DB cluster in a VPC
](USER_VPC.Scenarios.md)
+ [
# Tutorial: Create a VPC for use with a DB cluster (IPv4 only)
](CHAP_Tutorials.WebServerDB.CreateVPC.md)
+ [
# Tutorial: Create a VPC for use with a DB cluster (dual-stack mode)
](CHAP_Tutorials.CreateVPCDualStack.md)
Following, you can find a discussion about VPC functionality relevant to Amazon Aurora DB clusters. For more information about Amazon VPC, see [Amazon VPC Getting Started Guide](https://docs.aws.amazon.com/AmazonVPC/latest/GettingStartedGuide/) and [Amazon VPC User Guide](https://docs.aws.amazon.com/vpc/latest/userguide/).
# Working with a DB cluster in a VPC
Your DB cluster is in a virtual private cloud (VPC). A VPC is a virtual network that is logically isolated from other virtual networks in the AWS Cloud. Amazon VPC makes it possible for you to launch AWS resources, such as an Amazon Aurora DB cluster or Amazon EC2 instance, into a VPC. The VPC can either be a default VPC that comes with your account or one that you create. All VPCs are associated with your AWS account.
Your default VPC has three subnets that you can use to isolate resources inside the VPC. The default VPC also has an internet gateway that can be used to provide access to resources inside the VPC from outside the VPC.
For a list of scenarios involving Amazon Aurora DB clusters in a VPC , see [Scenarios for accessing a DB cluster in a VPC](USER_VPC.Scenarios.md).
**Topics**
+ [
## Working with a DB cluster in a VPC
](#Overview.RDSVPC.Create)
+ [
## VPC encryption control
](#USER_VPC.EncryptionControl)
+ [
## Working with DB subnet groups
](#USER_VPC.Subnets)
+ [
## Shared subnets
](#USER_VPC.Shared_subnets)
+ [
## Amazon Aurora IP addressing
](#USER_VPC.IP_addressing)
+ [
## Hiding a DB cluster in a VPC from the internet
](#USER_VPC.Hiding)
+ [
## Creating a DB cluster in a VPC
](#USER_VPC.InstanceInVPC)
In the following tutorials, you can learn to create a VPC that you can use for a common Amazon Aurora scenario:
+ [Tutorial: Create a VPC for use with a DB cluster (IPv4 only)](CHAP_Tutorials.WebServerDB.CreateVPC.md)
+ [Tutorial: Create a VPC for use with a DB cluster (dual-stack mode)](CHAP_Tutorials.CreateVPCDualStack.md)
## Working with a DB cluster in a VPC
Here are some tips on working with a DB cluster in a VPC:
+ Your VPC must have at least two subnets. These subnets must be in two different Availability Zones in the AWS Region where you want to deploy your DB cluster. A *subnet* is a segment of a VPC's IP address range that you can specify and that you can use to group DB clusters based on your security and operational needs.
+ If you want your DB cluster in the VPC to be publicly accessible, make sure to turn on the VPC attributes *DNS hostnames* and *DNS resolution*.
+ Your VPC must have a DB subnet group that you create. You create a DB subnet group by specifying the subnets you created. Amazon Aurora chooses a subnet and an IP address within that subnet to associate with the primary DB instance in your DB cluster. The primary DB instance uses the Availability Zone that contains the subnet.
+ Your VPC must have a VPC security group that allows access to the DB cluster.
For more information, see [Scenarios for accessing a DB cluster in a VPC](USER_VPC.Scenarios.md).
+ The CIDR blocks in each of your subnets must be large enough to accommodate spare IP addresses for Amazon Aurora to use during maintenance activities, including failover and compute scaling. For example, a range such as 10.0.0.0/24 and 10.0.1.0/24 is typically large enough.
+ A VPC can have an *instance tenancy* attribute of either *default* or *dedicated*. All default VPCs have the instance tenancy attribute set to default, and a default VPC can support any DB instance class.
If you choose to have your DB cluster in a dedicated VPC where the instance tenancy attribute is set to dedicated, the DB instance class of your DB cluster must be one of the approved Amazon EC2 dedicated instance types. For example, the r5.large EC2 dedicated instance corresponds to the db.r5.large DB instance class. For information about instance tenancy in a VPC, see [Dedicated instances](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/dedicated-instance.html) in the *Amazon Elastic Compute Cloud User Guide*.
For more information about the instance types that can be in a dedicated instance, see [Amazon EC2 dedicated instances](https://aws.amazon.com/ec2/purchasing-options/dedicated-instances/) on the Amazon EC2 pricing page.
**Note**
When you set the instance tenancy attribute to dedicated for a DB cluster, it doesn't guarantee that the DB cluster will run on a dedicated host.
## VPC encryption control
VPC encryption controls allow you to enforce encryption-in-transit for all network traffic within your VPCs. Use encryption control to meet regulatory compliance requirements by ensuring that only encryption-capable Nitro-based hardware can be provisioned in designated VPCs. Encryption control also catches compatibility issues at API request time rather than during provisioning. Your existing workloads continue operating and only new incompatible requests are blocked.
Set your VPC encryption controls by setting the VPC control mode to :
+ *disabled* (default)
+ *monitor*
+ *enforced*
To check the current control mode for your VPC, use the AWS Management Console or [DescribeVpcs](https://docs.aws.amazon.com//AWSEC2/latest/APIReference/API_DescribeVpcs.html) CLI or API command.
If your VPC enforces encryption, you can only provision Nitro-based DB clusters that support encryption in transit in that VPC. For more information see, [DB instance class types](Concepts.DBInstanceClass.Types.md). For information about Nitro instances, see [Instances built on the AWS Nitro System](https://docs.aws.amazon.com/ec2/latest/instancetypes/ec2-nitro-instances.html) in the *Amazon EC2 User Guide*.
**Note**
If you try to provision incompatible DB clusters in an encryption-enforced VPC, Aurora returns a `VpcEncryptionControlViolationException` exception.
For Aurora Serverless for MySQL and PostreSQL, encryption control requires platform version 3 or higher.
## Working with DB subnet groups
*Subnets* are segments of a VPC's IP address range that you designate to group your resources based on security and operational needs. A *DB subnet group* is a collection of subnets (typically private) that you create in a VPC and that you then designate for your DB clusters. By using a DB subnet group, you can specify a particular VPC when creating DB clusters using the AWS CLI or RDS API. If you use the console, you can choose the VPC and subnet groups you want to use.
Each DB subnet group should have subnets in at least two Availability Zones in a given AWS Region. When creating a DB cluster in a VPC, you choose a DB subnet group for it. From the DB subnet group, Amazon Aurora chooses a subnet and an IP address within that subnet to associate with the primary DB instance in your DB cluster. The DB uses the Availability Zone that contains the subnet. Aurora always assigns an IP address from a subnet that has free IP address space.
The subnets in a DB subnet group are either public or private. The subnets are public or private, depending on the configuration that you set for their network access control lists (network ACLs) and routing tables. For a DB cluster to be publicly accessible, all of the subnets in its DB subnet group must be public. If a subnet that's associated with a publicly accessible DB cluster changes from public to private, it can affect DB cluster availability.
To create a DB subnet group that supports dual-stack mode, make sure that each subnet that you add to the DB subnet group has an Internet Protocol version 6 (IPv6) CIDR block associated with it. For more information, see [Amazon Aurora IP addressing](#USER_VPC.IP_addressing) and [Migrating to IPv6](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-migrate-ipv6.html) in the *Amazon VPC User Guide.*
When Amazon Aurora creates a DB cluster in a VPC, it assigns a network interface to your DB cluster by using an IP address from your DB subnet group. However, we strongly recommend that you use the Domain Name System (DNS) name to connect to your DB cluster. We recommend this because the underlying IP address changes during failover.
**Note**
For each DB cluster that you run in a VPC, make sure to reserve at least one address in each subnet in the DB subnet group for use by Amazon Aurora for recovery actions.
## Shared subnets
You can create a DB cluster in a shared VPC.
Some considerations to keep in mind while using shared VPCs:
+ You can move a DB cluster from a shared VPC subnet to a non-shared VPC subnet and vice-versa.
+ Participants in a shared VPC must create a security group in the VPC to allow them to create a DB cluster.
+ Owners and participants in a shared VPC can access the database by using SQL queries. However, only the creator of a resource can make any API calls on the resource.
## Amazon Aurora IP addressing
IP addresses enable resources in your VPC to communicate with each other, and with resources over the internet. Amazon Aurora supports both IPv4 and IPv6 addressing protocols. By default, Amazon Aurora and Amazon VPC use the IPv4 addressing protocol. You can't turn off this behavior. When you create a VPC, make sure to specify an IPv4 CIDR block (a range of private IPv4 addresses). You can optionally assign an IPv6 CIDR block to your VPC and subnets, and assign IPv6 addresses from that block to DB clusters in your subnet.
Support for the IPv6 protocol expands the number of supported IP addresses. By using the IPv6 protocol, you ensure that you have sufficient available addresses for the future growth of the internet. New and existing RDS resources can use IPv4 and IPv6 addresses within your VPC. Configuring, securing, and translating network traffic between the two protocols used in different parts of an application can cause operational overhead. You can standardize on the IPv6 protocol for Amazon RDS resources to simplify your network configuration.
**Topics**
+ [
### IPv4 addresses
](#USER_VPC.IP_addressing.IPv4)
+ [
### IPv6 addresses
](#USER_VPC.IP_addressing.IPv6)
+ [
### Dual-stack mode
](#USER_VPC.IP_addressing.dual-stack-mode)
### IPv4 addresses
When you create a VPC, you must specify a range of IPv4 addresses for the VPC in the form of a CIDR block, such as `10.0.0.0/16`. A *DB subnet group* defines the range of IP addresses in this CIDR block that a DB cluster can use. These IP addresses can be private or public.
A private IPv4 address is an IP address that's not reachable over the internet. You can use private IPv4 addresses for communication between your DB cluster and other resources, such as Amazon EC2 instances, in the same VPC. Each DB cluster has a private IP address for communication in the VPC.
A public IP address is an IPv4 address that's reachable from the internet. You can use public addresses for communication between your DB cluster and resources on the internet, such as a SQL client. You control whether your DB cluster receives a public IP address.
Amazon RDS uses Public Elastic IPv4 addresses from EC2's public IPv4 address pool for publicly accessible database instances. These IP addresses are visible in your AWS account when using the `describe-addresses` CLI, API or viewing the Elastic IPs (EIP) section in the AWS Management Console. Each RDS-managed IP address is marked with a `service_managed` attribute set to `"rds"`.
While these IPs are visible in your account, they remain fully managed by Amazon RDS and cannot be modified or released. Amazon RDS releases IPs back into the public IPv4 address pool when no longer in use.
CloudTrail logs API calls related to RDS's EIP, such as the `AllocateAddress`. These API calls are invoked by the Service Principal `rds.amazonaws.com`.
**Note**
IPs allocated by Amazon RDS do not count against your account's EIP limits.
For a tutorial that shows you how to create a VPC with only private IPv4 addresses that you can use for a common Amazon Aurora scenario, see [Tutorial: Create a VPC for use with a DB cluster (IPv4 only)](CHAP_Tutorials.WebServerDB.CreateVPC.md).
### IPv6 addresses
You can optionally associate an IPv6 CIDR block with your VPC and subnets, and assign IPv6 addresses from that block to the resources in your VPC. Each IPv6 address is globally unique.
The IPv6 CIDR block for your VPC is automatically assigned from Amazon's pool of IPv6 addresses. You can't choose the range yourself.
When connecting to an IPv6 address, make sure that the following conditions are met:
+ The client is configured so that client to database traffic over IPv6 is allowed.
+ RDS security groups used by the DB instance are configured correctly so that client to database traffic over IPv6 is allowed.
+ The client operating system stack allows traffic on the IPv6 address, and operating system drivers and libraries are configured to choose the correct default DB instance endpoint (either IPv4 or IPv6).
For more information about IPv6, see [ IP Addressing](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-ip-addressing.html) in the *Amazon VPC User Guide*.
### Dual-stack mode
A DB cluster runs in dual-stack mode when it can communicate over both IPv4 and IPv6 addressing protocols. Resources can then communicate with the DB cluster using either IPv4, IPv6, or both protocols. Private dual-stack mode DB instances have IPv6 endpoints that RDS restricts to VPC access only, ensuring your IPv6 endpoints remain private. Public dual-stack mode DB instances provide both IPv4 and IPv6 endpoints that you can access from the internet.
**Topics**
+ [
#### Dual-stack mode and DB subnet groups
](#USER_VPC.IP_addressing.dual-stack-db-subnet-groups)
+ [
#### Working with dual-stack mode DB instances
](#USER_VPC.IP_addressing.dual-stack-working-with)
+ [
#### Modifying IPv4-only DB clusters to use dual-stack mode
](#USER_VPC.IP_addressing.dual-stack-modifying-ipv4)
+ [
#### Availability of dual-stack network DB clusters
](#USER_VPC.IP_addressing.dual-stack-availability)
+ [
#### Limitations for dual-stack network DB clusters
](#USER_VPC.IP_addressing.dual-stack-limitations)
For a tutorial that shows you how to create a VPC with both IPv4 and IPv6 addresses that you can use for a common Amazon Aurora scenario, see [Tutorial: Create a VPC for use with a DB cluster (dual-stack mode)](CHAP_Tutorials.CreateVPCDualStack.md).
#### Dual-stack mode and DB subnet groups
To use dual-stack mode, make sure that each subnet in the DB subnet group that you associate with the DB cluster has an IPv6 CIDR block associated with it. You can create a new DB subnet group or modify an existing DB subnet group to meet this requirement. After a DB cluster is in dual-stack mode, clients can connect to it normally. Make sure that client security firewalls and RDS DB instance security groups are accurately configured to allow traffic over IPv6. To connect, clients use the DB cluster primary instance's endpoint. Client applications can specify which protocol is preferred when connecting to a database. In dual-stack mode, the DB cluster detects the client's preferred network protocol, either IPv4 or IPv6, and uses that protocol for the connection.
If a DB subnet group stops supporting dual-stack mode because of subnet deletion or CIDR disassociation, there's a risk of an incompatible network state for DB instances that are associated with the DB subnet group. Also, you can't use the DB subnet group when you create a new dual-stack mode DB cluster.
To determine whether a DB subnet group supports dual-stack mode by using the AWS Management Console, view the **Network type** on the details page of the DB subnet group. To determine whether a DB subnet group supports dual-stack mode by using the AWS CLI, run the [describe-db-subnet-groups](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-subnet-groups.html) command and view `SupportedNetworkTypes` in the output.
Read replicas are treated as independent DB instances and can have a network type that's different from the primary DB instance. If you change the network type of a read replica's primary DB instance, the read replica isn't affected. When you are restoring a DB instance, you can restore it to any network type that's supported.
#### Working with dual-stack mode DB instances
When you create or modify a DB cluster, you can specify dual-stack mode to allow your resources to communicate with your DB cluster over IPv4, IPv6, or both.
When you use the AWS Management Console to create or modify a DB instance, you can specify dual-stack mode in the **Network type** section. The following image shows the **Network type** section in the console.
![\[Network type section in the console with Dual-stack mode selected.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/dual-stack-mode.png)
When you use the AWS CLI to create or modify a DB cluster, set the `--network-type` option to `DUAL` to use dual-stack mode. When you use the RDS API to create or modify a DB cluster, set the `NetworkType` parameter to `DUAL` to use dual-stack mode. When you are modifying the network type of a DB instance, downtime is possible. If dual-stack mode isn't supported by the specified DB engine version or DB subnet group, the `NetworkTypeNotSupported` error is returned.
For more information about creating a DB cluster, see [Creating an Amazon Aurora DB cluster](Aurora.CreateInstance.md). For more information about modifying a DB cluster, see [Modifying an Amazon Aurora DB cluster](Aurora.Modifying.md).
To determine whether a DB cluster is in dual-stack mode by using the console, view the **Network type** on the **Connectivity & security** tab for the DB cluster.
#### Modifying IPv4-only DB clusters to use dual-stack mode
You can modify an IPv4-only DB cluster to use dual-stack mode. To do so, change the network type of the DB cluster. The modification might result in downtime.
It is recommended that you change the network type of your Amazon Aurora DB clusters during a maintenance window. Currently, setting the network type of new instances to dual-stack mode isn't supported. You can set network type manually by using the `modify-db-cluster` command.
Before modifying a DB cluster to use dual-stack mode, make sure that its DB subnet group supports dual-stack mode. If the DB subnet group associated with the DB cluster doesn't support dual-stack mode, specify a different DB subnet group that supports it when you modify the DB cluster. Modifying the DB subnet group of a DB cluster can cause downtime.
If you modify the DB subnet group of a DB cluster before you change the DB cluster to use dual-stack mode, make sure that the DB subnet group is valid for the DB cluster before and after the change.
We recommend that you run the [modify-db-cluster](https://docs.aws.amazon.com/cli/latest/reference/rds/modify-db-cluster.html) API with only the `--network-type` parameter with value `DUAL` to change the network of an Amazon Aurora cluster to dual-stack mode. Adding other parameters along with the `--network-type` parameter in the same API call could result in downtime.
If you can't connect to the DB cluster after the change, make sure that the client and database security firewalls and route tables are accurately configured to allow traffic to the database on the selected network (either IPv4 or IPv6). You might also need to modify operating system parameter, libraries, or drivers to connect using an IPv6 address.
**To modify an IPv4-only DB cluster to use dual-stack mode**
1. Modify a DB subnet group to support dual-stack mode, or create a DB subnet group that supports dual-stack mode:
1. Associate an IPv6 CIDR block with your VPC.
For instructions, see [ Add an IPv6 CIDR block to your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/modify-vpcs.html#vpc-associate-ipv6-cidr) in the *Amazon VPC User Guide*.
1. Attach the IPv6 CIDR block to all of the subnets in your the DB subnet group.
For instructions, see [ Add an IPv6 CIDR block to your subnet](https://docs.aws.amazon.com/vpc/latest/userguide/modify-subnets.html#subnet-associate-ipv6-cidr) in the *Amazon VPC User Guide*.
1. Confirm that the DB subnet group supports dual-stack mode.
If you are using the AWS Management Console, select the DB subnet group, and make sure that the **Supported network types** value is **Dual, IPv4**.
If you are using the AWS CLI, run the [describe-db-subnet-groups](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-subnet-groups.html) command, and make sure that the `SupportedNetworkType` value for the DB instance is `Dual, IPv4`.
1. Modify the security group associated with the DB cluster to allow IPv6 connections to the database, or create a new security group that allows IPv6 connections.
For instructions, see [ Security group rules](https://docs.aws.amazon.com/vpc/latest/userguide/security-group-rules.html) in the *Amazon VPC User Guide*.
1. Modify the DB cluster to support dual-stack mode. To do so, set the **Network type** to **Dual-stack mode**.
If you are using the console, make sure that the following settings are correct:
+ **Network type** – **Dual-stack mode**
![\[Network type section in the console with Dual-stack mode selected.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/dual-stack-mode.png)
+ **DB subnet group** – The DB subnet group that you configured in a previous step
+ **Security group** – The security that you configured in a previous step
If you are using the AWS CLI, make sure that the following settings are correct:
+ `--network-type` – `dual`
+ `--db-subnet-group-name` – The DB subnet group that you configured in a previous step
+ `--vpc-security-group-ids` – The VPC security group that you configured in a previous step
For example:
```
aws rds modify-db-cluster --db-cluster-identifier my-cluster --network-type "DUAL"
```
1. Confirm that the DB cluster supports dual-stack mode.
If you are using the console, choose the **Configuration** tab for the DB cluster. On that tab, make sure that the **Network type** value is **Dual-stack mode**.
If you are using the AWS CLI, run the [ describe-db-clusters](https://docs.aws.amazon.com/cli/latest/reference/rds/describe-db-clusters.html) command, and make sure that the `NetworkType` value for the DB cluster is `dual`.
Run the `dig` command on the writer DB instance endpoint to identify the IPv6 address associated with it.
```
dig db-instance-endpoint AAAA
```
Use the writer DB instance endpoint, not the IPv6 address, to connect to the DB cluster.
#### Availability of dual-stack network DB clusters
Dual-stack network DB clusters are available in all AWS Regions except for the following:
+ Asia Pacific (Hyderabad)
+ Asia Pacific (Malaysia)
+ Asia Pacific (Melbourne)
+ Asia Pacific (Thailand)
+ Canada West (Calgary)
+ Europe (Spain)
+ Europe (Zurich)
+ Israel (Tel Aviv)
+ Mexico (Central)
+ Middle East (UAE)
The following DB engine versions support dual-stack network DB clusters:
+ Aurora MySQL versions:
+ 3.02 and higher 3 versions
+ 2.09.1 and higher 2 versions
For more information about Aurora MySQL versions, see the [https://docs.aws.amazon.com/AmazonRDS/latest/AuroraMySQLReleaseNotes/Welcome.html](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraMySQLReleaseNotes/Welcome.html).
+ Aurora PostgreSQL versions:
+ 15.2 and all higher versions
+ 14.3 and higher 14 versions
+ 13.7 and higher 13 versions
For more information about Aurora PostgreSQL versions, see the [https://docs.aws.amazon.com/AmazonRDS/latest/AuroraPostgreSQLReleaseNotes/Welcome.html](https://docs.aws.amazon.com/AmazonRDS/latest/AuroraPostgreSQLReleaseNotes/Welcome.html).
#### Limitations for dual-stack network DB clusters
The following limitations apply to dual-stack network DB clusters:
+ DB clusters can't use the IPv6 protocol exclusively. They can use IPv4 exclusively, or they can use the IPv4 and IPv6 protocol (dual-stack mode).
+ Amazon RDS doesn't support native IPv6 subnets.
+ You can't use RDS Proxy with dual-stack mode DB clusters.
## Hiding a DB cluster in a VPC from the internet
One common Amazon Aurora scenario is to have a VPC in which you have an Amazon EC2 instance with a public-facing web application and a DB cluster with a database that isn't publicly accessible. For example, you can create a VPC that has a public subnet and a private subnet. EC2 instances that function as web servers can be deployed in the public subnet. The DB clusters are deployed in the private subnet. In such a deployment, only the web servers have access to the DB clusters. For an illustration of this scenario, see [A DB cluster in a VPC accessed by an Amazon EC2 instance in the same VPC](USER_VPC.Scenarios.md#USER_VPC.Scenario1).
When you launch a DB cluster inside a VPC, the DB cluster has a private IP address for traffic inside the VPC. This private IP address isn't publicly accessible. You can use the **Public access** option to designate whether the DB cluster also has a public IP address in addition to the private IP address. If the DB cluster is designated as publicly accessible, its DNS endpoint resolves to the private IP address from within the VPC. It resolves to the public IP address from outside of the VPC. Access to the DB cluster is ultimately controlled by the security group it uses. That public access is not permitted if the security group assigned to the DB cluster doesn't include inbound rules that permit it. In addition, for a DB cluster to be publicly accessible, the subnets in its DB subnet group must have an internet gateway. For more information, see [Can't connect to Amazon RDS DB instance](CHAP_Troubleshooting.md#CHAP_Troubleshooting.Connecting)
You can modify a DB cluster to turn on or off public accessibility by modifying the **Public access** option. The following illustration shows the **Public access** option in the **Additional connectivity configuration** section. To set the option, open the **Additional connectivity configuration** section in the **Connectivity** section.
![\[Set your database Public access option in the Additional connectivity configuration section to No.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/VPC-example4.png)
For information about modifying a DB instance to set the **Public access** option, see [Modifying a DB instance in a DB cluster](Aurora.Modifying.md#Aurora.Modifying.Instance).
## Creating a DB cluster in a VPC
The following procedures help you create a DB cluster in a VPC. To use the default VPC, you can begin with step 2, and use the VPC and DB subnet group have already been created for you. If you want to create an additional VPC, you can create a new VPC.
**Note**
If you want your DB cluster in the VPC to be publicly accessible, you must update the DNS information for the VPC by enabling the VPC attributes *DNS hostnames* and *DNS resolution*. For information about updating the DNS information for a VPC instance, see [Updating DNS support for your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-dns.html).
Follow these steps to create a DB instance in a VPC:
+ [Step 1: Create a VPC](#USER_VPC.CreatingVPC)
+ [Step 2: Create a DB subnet group](#USER_VPC.CreateDBSubnetGroup)
+ [Step 3: Create a VPC security group](#USER_VPC.CreateVPCSecurityGroup)
+ [Step 4: Create a DB instance in the VPC](#USER_VPC.CreateDBInstanceInVPC)
### Step 1: Create a VPC
Create a VPC with subnets in at least two Availability Zones. You use these subnets when you create a DB subnet group. If you have a default VPC, a subnet is automatically created for you in each Availability Zone in the AWS Region.
For more information, see [Create a VPC with private and public subnets](CHAP_Tutorials.WebServerDB.CreateVPC.md#CHAP_Tutorials.WebServerDB.CreateVPC.VPCAndSubnets), or see [Create a VPC](https://docs.aws.amazon.com/vpc/latest/userguide/working-with-vpcs.html#Create-VPC) in the *Amazon VPC User Guide*.
### Step 2: Create a DB subnet group
A DB subnet group is a collection of subnets (typically private) that you create for a VPC and that you then designate for your DB clusters. A DB subnet group allows you to specify a particular VPC when you create DB clusters using the AWS CLI or RDS API. If you use the console, you can just choose the VPC and subnets you want to use. Each DB subnet group must have at least one subnet in at least two Availability Zones in the AWS Region. As a best practice, each DB subnet group should have at least one subnet for every Availability Zone in the AWS Region.
For a DB cluster to be publicly accessible, the subnets in the DB subnet group must have an internet gateway. For more information about internet gateways for subnets, see [Connect to the internet using an internet gateway](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_Internet_Gateway.html) in the *Amazon VPC User Guide*.
When you create a DB cluster in a VPC, you can choose a DB subnet group. Amazon Aurora chooses a subnet and an IP address within that subnet to associate with your DB cluster. If no DB subnet groups exist, Amazon Aurora creates a default subnet group when you create a DB cluster. Amazon Aurora creates and associates an Elastic Network Interface to your DB cluster with that IP address. The DB cluster uses the Availability Zone that contains the subnet.
In this step, you create a DB subnet group and add the subnets that you created for your VPC.
**To create a DB subnet group**
1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Subnet groups**.
1. Choose **Create DB Subnet Group**.
1. For **Name**, type the name of your DB subnet group.
1. For **Description**, type a description for your DB subnet group.
1. For **VPC**, choose the default VPC or the VPC that you created.
1. In the **Add subnets** section, choose the Availability Zones that include the subnets from **Availability Zones**, and then choose the subnets from **Subnets**.
![\[Create a DB subnet group.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/RDSVPC101.png)
1. Choose **Create**.
Your new DB subnet group appears in the DB subnet groups list on the RDS console. You can choose the DB subnet group to see details, including all of the subnets associated with the group, in the details pane at the bottom of the window.
### Step 3: Create a VPC security group
Before you create your DB cluster, you can create a VPC security group to associate with your DB cluster. If you don't create a VPC security group, you can use the default security group when you create a DB cluster. For instructions on how to create a security group for your DB cluster, see [Create a VPC security group for a private DB cluster](CHAP_Tutorials.WebServerDB.CreateVPC.md#CHAP_Tutorials.WebServerDB.CreateVPC.SecurityGroupDB), or see [Control traffic to resources using security groups](https://docs.aws.amazon.com/vpc/latest/userguide/VPC_SecurityGroups.html) in the *Amazon VPC User Guide*.
### Step 4: Create a DB instance in the VPC
In this step, you create a DB cluster and use the VPC name, the DB subnet group, and the VPC security group you created in the previous steps.
**Note**
If you want your DB cluster in the VPC to be publicly accessible, you must enable the VPC attributes *DNS hostnames* and *DNS resolution*. For more information, see [DNS attributes for your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-dns.html) in the *Amazon VPC User Guide*.
For details on how to create a DB cluster, see [Creating an Amazon Aurora DB cluster](Aurora.CreateInstance.md).
When prompted in the **Connectivity** section, enter the VPC name, the DB subnet group, and the VPC security group.
**Note**
Updating VPCs isn't currently supported for Aurora DB clusters.
# Scenarios for accessing a DB cluster in a VPC
Amazon Aurora supports the following scenarios for accessing a DB cluster in a VPC:
+ [An Amazon EC2 instance in the same VPC](#USER_VPC.Scenario1)
+ [An EC2 instance in a different VPC](#USER_VPC.Scenario3)
+ [A client application through the internet](#USER_VPC.Scenario4)
+ [A private network](#USER_VPC.NotPublic)
## A DB cluster in a VPC accessed by an Amazon EC2 instance in the same VPC
A common use of a DB cluster in a VPC is to share data with an application server that is running in an Amazon EC2 instance in the same VPC.
The following diagram shows this scenario.
![\[VPC scenario with a public web server and a private database.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/con-VPC-sec-grp-aurora.png)
The simplest way to manage access between EC2 instances and DB clusters in the same VPC is to do the following:
+ Create a VPC security group for your DB clusters to be in. This security group can be used to restrict access to the DB clusters. For example, you can create a custom rule for this security group. This might allow TCP access using the port that you assigned to the DB cluster when you created it and an IP address you use to access the DB cluster for development or other purposes.
+ Create a VPC security group for your EC2 instances (web servers and clients) to be in. This security group can, if needed, allow access to the EC2 instance from the internet by using the VPC's routing table. For example, you can set rules on this security group to allow TCP access to the EC2 instance over port 22.
+ Create custom rules in the security group for your DB clusters that allow connections from the security group you created for your EC2 instances. These rules might allow any member of the security group to access the DB clusters.
There is an additional public and private subnet in a separate Availability Zone. An RDS DB subnet group requires a subnet in at least two Availability Zones. The additional subnet makes it easy to switch to a Multi-AZ DB instance deployment in the future.
For a tutorial that shows you how to create a VPC with both public and private subnets for this scenario, see [Tutorial: Create a VPC for use with a DB cluster (IPv4 only)](CHAP_Tutorials.WebServerDB.CreateVPC.md).
**Tip**
You can set up network connectivity between an Amazon EC2 instance and a DB cluster automatically when you create the DB cluster. For more information, see [Configure automatic network connectivity with an EC2 instance](Aurora.CreateInstance.md#Aurora.CreateInstance.Prerequisites.VPC.Automatic) .
**To create a rule in a VPC security group that allows connections from another security group, do the following:**
1. Sign in to the AWS Management Console and open the Amazon VPC console at [https://console.aws.amazon.com/vpc](https://console.aws.amazon.com/vpc).
1. In the navigation pane, choose **Security groups**.
1. Choose or create a security group for which you want to allow access to members of another security group. In the preceding scenario, this is the security group that you use for your DB clusters. Choose the **Inbound rules** tab, and then choose **Edit inbound rules**.
1. On the **Edit inbound rules** page, choose **Add rule**.
1. For **Type**, choose the entry that corresponds to the port you used when you created your DB cluster, such as **MYSQL/Aurora**.
1. In the **Source** box, start typing the ID of the security group, which lists the matching security groups. Choose the security group with members that you want to have access to the resources protected by this security group. In the scenario preceding, this is the security group that you use for your EC2 instance.
1. If required, repeat the steps for the TCP protocol by creating a rule with **All TCP** as the **Type** and your security group in the **Source** box. If you intend to use the UDP protocol, create a rule with **All UDP** as the **Type** and your security group in **Source**.
1. Choose **Save rules**.
The following screen shows an inbound rule with a security group for its source.
![\[Adding a security group to another security group's rules.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/con-vpc-add-sg-rule.png)
For more information about connecting to the DB cluster from your EC2 instance, see [Connecting to an Amazon Aurora DB cluster](Aurora.Connecting.md).
## A DB cluster in a VPC accessed by an EC2 instance in a different VPC
When your DB clusters is in a different VPC from the EC2 instance you are using to access it, you can use VPC peering to access the DB cluster.
The following diagram shows this scenario.
![\[A DB instance in a VPC accessed by an Amazon EC2 instance in a different VPC.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/RDSVPC2EC2VPC-aurora.png)
A VPC peering connection is a networking connection between two VPCs that enables you to route traffic between them using private IP addresses. Resources in either VPC can communicate with each other as if they are within the same network. You can create a VPC peering connection between your own VPCs, with a VPC in another AWS account, or with a VPC in a different AWS Region. To learn more about VPC peering, see [VPC peering](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-peering.html) in the *Amazon Virtual Private Cloud User Guide*.
## A DB cluster in a VPC accessed by a client application through the internet
To access a DB clusters in a VPC from a client application through the internet, you configure a VPC with a single public subnet, and an internet gateway to enable communication over the internet.
The following diagram shows this scenario.
![\[A DB cluster in a VPC accessed by a client application through the internet.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/GS-VPC-network-aurora.png)
We recommend the following configuration:
+ A VPC of size /16 (for example CIDR: 10.0.0.0/16). This size provides 65,536 private IP addresses.
+ A subnet of size /24 (for example CIDR: 10.0.0.0/24). This size provides 256 private IP addresses.
+ An Amazon Aurora DB cluster that is associated with the VPC and the subnet. Amazon RDS assigns an IP address within the subnet to your DB cluster.
+ An internet gateway which connects the VPC to the internet and to other AWS products.
+ A security group associated with the DB cluster. The security group's inbound rules allow your client application to access to your DB cluster.
For information about creating a DB clusters in a VPC, see [Creating a DB cluster in a VPC](USER_VPC.WorkingWithRDSInstanceinaVPC.md#USER_VPC.InstanceInVPC).
## A DB cluster in a VPC accessed by a private network
If your DB cluster isn't publicly accessible, you have the following options for accessing it from a private network:
+ An AWS Site-to-Site VPN connection. For more information, see [What is AWS Site-to-Site VPN?](https://docs.aws.amazon.com/vpn/latest/s2svpn/VPC_VPN.html)
+ An Direct Connect connection. For more information, see [What is Direct Connect?](https://docs.aws.amazon.com/directconnect/latest/UserGuide/Welcome.html)
+ An AWS Client VPN connection. For more information, see [What is AWS Client VPN?](https://docs.aws.amazon.com//vpn/latest/clientvpn-admin/what-is.html)
The following diagram shows a scenario with an AWS Site-to-Site VPN connection.
![\[DB clusters in a VPC accessed by a private network.\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/site-to-site-vpn-connection-aurora.png)
For more information, see [Internetwork traffic privacy](inter-network-traffic-privacy.md).
# Tutorial: Create a VPC for use with a DB cluster (IPv4 only)
A common scenario includes a DB cluster in a virtual private cloud (VPC) based on the Amazon VPC service. This VPC shares data with a web server that is running in the same VPC. In this tutorial, you create the VPC for this scenario.
The following diagram shows this scenario. For information about other scenarios, see [Scenarios for accessing a DB cluster in a VPC](USER_VPC.Scenarios.md).
![\[Single VPC scenario\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/con-VPC-sec-grp-aurora.png)
Your DB cluster needs to be available only to your web server, and not to the public internet. Thus, you create a VPC with both public and private subnets. The web server is hosted in the public subnet, so that it can reach the public internet. The DB cluster is hosted in a private subnet. The web server can connect to the DB cluster because it is hosted within the same VPC. But the DB cluster isn't available to the public internet, providing greater security.
This tutorial configures an additional public and private subnet in a separate Availability Zone. These subnets aren't used by the tutorial. An RDS DB subnet group requires a subnet in at least two Availability Zones. The additional subnet makes it easier to configure more than one Aurora DB instance.
This tutorial describes configuring a VPC for Amazon Aurora DB clusters. For a tutorial that shows you how to create a web server for this VPC scenario, see [Tutorial: Create a web server and an Amazon Aurora DB cluster](TUT_WebAppWithRDS.md). For more information about Amazon VPC, see [Amazon VPC Getting Started Guide](https://docs.aws.amazon.com/AmazonVPC/latest/GettingStartedGuide/) and [Amazon VPC User Guide](https://docs.aws.amazon.com/vpc/latest/userguide/).
**Tip**
You can set up network connectivity between an Amazon EC2 instance and a DB cluster automatically when you create the DB cluster. The network configuration is similar to the one described in this tutorial. For more information, see [Configure automatic network connectivity with an EC2 instance](Aurora.CreateInstance.md#Aurora.CreateInstance.Prerequisites.VPC.Automatic).
## Create a VPC with private and public subnets
Use the following procedure to create a VPC with both public and private subnets.
**To create a VPC and subnets**
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. In the top-right corner of the AWS Management Console, choose the Region to create your VPC in. This example uses the US West (Oregon) Region.
1. In the upper-left corner, choose **VPC dashboard**. To begin creating a VPC, choose **Create VPC**.
1. For **Resources to create** under **VPC settings**, choose **VPC and more**.
1. For the **VPC settings**, set these values:
+ **Name tag auto-generation** – **tutorial**
+ **IPv4 CIDR block** – **10.0.0.0/16**
+ **IPv6 CIDR block** – **No IPv6 CIDR block**
+ **Tenancy** – **Default**
+ **Number of Availability Zones (AZs)** – **2**
+ **Customize AZs** – Keep the default values.
+ **Number of public subnet** – **2**
+ **Number of private subnets** – **2**
+ **Customize subnets CIDR blocks** – Keep the default values.
+ **NAT gateways (\$1)** – **None**
+ **VPC endpoints** – **None**
+ **DNS options** – Keep the default values.
1. Choose **Create VPC**.
## Create a VPC security group for a public web server
Next, you create a security group for public access. To connect to public EC2 instances in your VPC, you add inbound rules to your VPC security group. These allow traffic to connect from the internet.
**To create a VPC security group**
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, choose **Security Groups**, and then choose **Create security group**.
1. On the **Create security group** page, set these values:
+ **Security group name:** **tutorial-securitygroup**
+ **Description:** **Tutorial Security Group**
+ **VPC:** Choose the VPC that you created earlier, for example: **vpc-*identifier* (tutorial-vpc)**
1. Add inbound rules to the security group.
1. Determine the IP address to use to connect to EC2 instances in your VPC using Secure Shell (SSH). To determine your public IP address, in a different browser window or tab, you can use the service at [https://checkip.amazonaws.com](https://checkip.amazonaws.com). An example of an IP address is `203.0.113.25/32`.
In many cases, you might connect through an internet service provider (ISP) or from behind your firewall without a static IP address. If so, find the range of IP addresses used by client computers.
**Warning**
If you use `0.0.0.0/0` for SSH access, you make it possible for all IP addresses to access your public instances using SSH. This approach is acceptable for a short time in a test environment, but it's unsafe for production environments. In production, authorize only a specific IP address or range of addresses to access your instances using SSH.
1. In the **Inbound rules** section, choose **Add rule**.
1. Set the following values for your new inbound rule to allow SSH access to your Amazon EC2 instance. If you do this, you can connect to your Amazon EC2 instance to install the web server and other utilities. You also connect to your EC2 instance to upload content for your web server.
+ **Type:** **SSH**
+ **Source:** The IP address or range from Step a, for example: **203.0.113.25/32**.
1. Choose **Add rule**.
1. Set the following values for your new inbound rule to allow HTTP access to your web server:
+ **Type:** **HTTP**
+ **Source:** **0.0.0.0/0**
1. Choose **Create security group** to create the security group.
Note the security group ID because you need it later in this tutorial.
## Create a VPC security group for a private DB cluster
To keep your DB cluster private, create a second security group for private access. To connect to private DB clusters in your VPC, you add inbound rules to your VPC security group that allow traffic from your web server only.
**To create a VPC security group**
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, choose **Security Groups**, and then choose **Create security group**.
1. On the **Create security group** page, set these values:
+ **Security group name:** **tutorial-db-securitygroup**
+ **Description:** **Tutorial DB Instance Security Group**
+ **VPC:** Choose the VPC that you created earlier, for example: **vpc-*identifier* (tutorial-vpc)**
1. Add inbound rules to the security group.
1. In the **Inbound rules** section, choose **Add rule**.
1. Set the following values for your new inbound rule to allow MySQL traffic on port 3306 from your Amazon EC2 instance. If you do this, you can connect from your web server to your DB cluster. By doing so, you can store and retrieve data from your web application to your database.
+ **Type:** **MySQL/Aurora**
+ **Source:** The identifier of the **tutorial-securitygroup** security group that you created previously in this tutorial, for example: **sg-9edd5cfb**.
1. Choose **Create security group** to create the security group.
## Create a DB subnet group
A *DB subnet group* is a collection of subnets that you create in a VPC and that you then designate for your DB clusters. A DB subnet group makes it possible for you to specify a particular VPC when creating DB clusters.
**To create a DB subnet group**
1. Identify the private subnets for your database in the VPC.
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **Subnets**.
1. Note the subnet IDs of the subnets named **tutorial-subnet-private1-us-west-2a** and **tutorial-subnet-private2-us-west-2b**.
You need the subnet IDs when you create your DB subnet group.
1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
Make sure that you connect to the Amazon RDS console, not to the Amazon VPC console.
1. In the navigation pane, choose **Subnet groups**.
1. Choose **Create DB subnet group**.
1. On the **Create DB subnet group** page, set these values in **Subnet group details**:
+ **Name:** **tutorial-db-subnet-group**
+ **Description:** **Tutorial DB Subnet Group**
+ **VPC:** **tutorial-vpc (vpc-*identifier*)**
1. In the **Add subnets** section, choose the **Availability Zones** and **Subnets**.
For this tutorial, choose **us-west-2a** and **us-west-2b** for the **Availability Zones**. For **Subnets**, choose the private subnets you identified in the previous step.
1. Choose **Create**.
Your new DB subnet group appears in the DB subnet groups list on the RDS console. You can choose the DB subnet group to see details in the details pane at the bottom of the window. These details include all of the subnets associated with the group.
**Note**
If you created this VPC to complete [Tutorial: Create a web server and an Amazon Aurora DB cluster](TUT_WebAppWithRDS.md), create the DB cluster by following the instructions in [Create an Amazon Aurora DB cluster](CHAP_Tutorials.WebServerDB.CreateDBCluster.md).
## Deleting the VPC
After you create the VPC and other resources for this tutorial, you can delete them if they are no longer needed.
**Note**
If you added resources in the VPC that you created for this tutorial, you might need to delete these before you can delete the VPC. For example, these resources might include Amazon EC2 instances or Amazon RDS DB clusters. For more information, see [Delete your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/working-with-vpcs.html#VPC_Deleting) in the *Amazon VPC User Guide*.
**To delete a VPC and related resources**
1. Delete the DB subnet group.
1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Subnet groups**.
1. Select the DB subnet group you want to delete, such as **tutorial-db-subnet-group**.
1. Choose **Delete**, and then choose **Delete** in the confirmation window.
1. Note the VPC ID.
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **VPCs**.
1. In the list, identify the VPC that you created, such as **tutorial-vpc**.
1. Note the **VPC ID** of the VPC that you created. You need the VPC ID in later steps.
1. Delete the security groups.
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **Security Groups**.
1. Select the security group for the Amazon RDS DB instance, such as **tutorial-db-securitygroup**.
1. For **Actions**, choose **Delete security groups**, and then choose **Delete** on the confirmation page.
1. On the **Security Groups** page, select the security group for the Amazon EC2 instance, such as **tutorial-securitygroup**.
1. For **Actions**, choose **Delete security groups**, and then choose **Delete** on the confirmation page.
1. Delete the VPC.
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **VPCs**.
1. Select the VPC you want to delete, such as **tutorial-vpc**.
1. For **Actions**, choose **Delete VPC**.
The confirmation page shows other resources that are associated with the VPC that will also be deleted, including the subnets associated with it.
1. On the confirmation page, enter **delete**, and then choose **Delete**.
# Tutorial: Create a VPC for use with a DB cluster (dual-stack mode)
A common scenario includes a DB cluster in a virtual private cloud (VPC) based on the Amazon VPC service. This VPC shares data with a public Amazon EC2 instance that is running in the same VPC.
In this tutorial, you create the VPC for this scenario that works with a database running in dual-stack mode. Dual-stack mode to enable connection over the IPv6 addressing protocol. For more information about IP addressing, see [Amazon Aurora IP addressing](USER_VPC.WorkingWithRDSInstanceinaVPC.md#USER_VPC.IP_addressing).
Dual-stack network clusters are supported in most regions. For more information see [Availability of dual-stack network DB clusters](USER_VPC.WorkingWithRDSInstanceinaVPC.md#USER_VPC.IP_addressing.dual-stack-availability). To see the limitations of dual-stack mode, see [Limitations for dual-stack network DB clusters](USER_VPC.WorkingWithRDSInstanceinaVPC.md#USER_VPC.IP_addressing.dual-stack-limitations).
The following diagram shows this scenario.
![\[VPC scenario for dual-stack mode\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/con-VPC-sec-grp-dual-stack-aurora.png)
For information about other scenarios, see [Scenarios for accessing a DB cluster in a VPC](USER_VPC.Scenarios.md).
Your DB cluster needs to be available only to your Amazon EC2 instance, and not to the public internet. Thus, you create a VPC with both public and private subnets. The Amazon EC2 instance is hosted in the public subnet, so that it can reach the public internet. The DB cluster is hosted in a private subnet. The Amazon EC2 instance can connect to the DB cluster because it's hosted within the same VPC. However, the DB cluster is not available to the public internet, providing greater security.
This tutorial configures an additional public and private subnet in a separate Availability Zone. These subnets aren't used by the tutorial. An RDS DB subnet group requires a subnet in at least two Availability Zones. The additional subnet makes it easy to configure more than one Aurora DB instance.
To create a DB cluster that uses dual-stack mode, specify **Dual-stack mode** for the **Network type** setting. You can also modify a DB cluster with the same setting. For more information about creating a DB cluster, see [Creating an Amazon Aurora DB cluster](Aurora.CreateInstance.md). For more information about modifying a DB cluster, see [Modifying an Amazon Aurora DB cluster](Aurora.Modifying.md).
This tutorial describes configuring a VPC for Amazon Aurora DB clusters. For more information about Amazon VPC, see [Amazon VPC User Guide](https://docs.aws.amazon.com/vpc/latest/userguide/).
## Create a VPC with private and public subnets
Use the following procedure to create a VPC with both public and private subnets.
**To create a VPC and subnets**
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. In the upper-right corner of the AWS Management Console, choose the Region to create your VPC in. This example uses the US East (Ohio) Region.
1. In the upper-left corner, choose **VPC dashboard**. To begin creating a VPC, choose **Create VPC**.
1. For **Resources to create** under **VPC settings**, choose **VPC and more**.
1. For the remaining **VPC settings**, set these values:
+ **Name tag auto-generation** – **tutorial-dual-stack**
+ **IPv4 CIDR block** – **10.0.0.0/16**
+ **IPv6 CIDR block** – **Amazon-provided IPv6 CIDR block**
+ **Tenancy** – **Default**
+ **Number of Availability Zones (AZs)** – **2**
+ **Customize AZs** – Keep the default values.
+ **Number of public subnet** – **2**
+ **Number of private subnets** – **2**
+ **Customize subnets CIDR blocks** – Keep the default values.
+ **NAT gateways (\$1)** – **None**
+ **Egress only internet gateway** – **No**
+ **VPC endpoints** – **None**
+ **DNS options** – Keep the default values.
**Note**
Amazon RDS requires at least two subnets in two different Availability Zones to support Multi-AZ DB instance deployments. This tutorial creates a Single-AZ deployment, but the requirement makes it easy to convert to a Multi-AZ DB instance deployment in the future.
1. Choose **Create VPC**.
## Create a VPC security group for a public Amazon EC2 instance
Next, you create a security group for public access. To connect to public EC2 instances in your VPC, add inbound rules to your VPC security group that allow traffic to connect from the internet.
**To create a VPC security group**
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, choose **Security Groups**, and then choose **Create security group**.
1. On the **Create security group** page, set these values:
+ **Security group name:** **tutorial-dual-stack-securitygroup**
+ **Description:** **Tutorial Dual-Stack Security Group**
+ **VPC:** Choose the VPC that you created earlier, for example: **vpc-*identifier* (tutorial-dual-stack-vpc)**
1. Add inbound rules to the security group.
1. Determine the IP address to use to connect to EC2 instances in your VPC using Secure Shell (SSH).
An example of an Internet Protocol version 4 (IPv4) address is `203.0.113.25/32`. An example of an Internet Protocol version 6 (IPv6) address range is `2001:db8:1234:1a00::/64`.
In many cases, you might connect through an internet service provider (ISP) or from behind your firewall without a static IP address. If so, find the range of IP addresses used by client computers.
**Warning**
If you use `0.0.0.0/0` for IPv4 or `::0` for IPv6, you make it possible for all IP addresses to access your public instances using SSH. This approach is acceptable for a short time in a test environment, but it's unsafe for production environments. In production, authorize only a specific IP address or range of addresses to access your instances.
1. In the **Inbound rules** section, choose **Add rule**.
1. Set the following values for your new inbound rule to allow Secure Shell (SSH) access to your Amazon EC2 instance. If you do this, you can connect to your EC2 instance to install SQL clients and other applications. Specify an IP address so you can access your EC2 instance:
+ **Type:** **SSH**
+ **Source:** The IP address or range from step a. An example of an IPv4 IP address is **203.0.113.25/32**. An example of an IPv6 IP address is **2001:DB8::/32**.
1. Choose **Create security group** to create the security group.
Note the security group ID because you need it later in this tutorial.
## Create a VPC security group for a private DB cluster
To keep your DB cluster private, create a second security group for private access. To connect to private DB clusters in your VPC, add inbound rules to your VPC security group. These allow traffic from your Amazon EC2 instance only.
**To create a VPC security group**
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, choose **Security Groups**, and then choose **Create security group**.
1. On the **Create security group** page, set these values:
+ **Security group name:** **tutorial-dual-stack-db-securitygroup**
+ **Description:** **Tutorial Dual-Stack DB Instance Security Group**
+ **VPC:** Choose the VPC that you created earlier, for example: **vpc-*identifier* (tutorial-dual-stack-vpc)**
1. Add inbound rules to the security group:
1. In the **Inbound rules** section, choose **Add rule**.
1. Set the following values for your new inbound rule to allow MySQL traffic on port 3306 from your Amazon EC2 instance. If you do, you can connect from your EC2 instance to your DB cluster. Doing this means that you can send data from your EC2 instance to your database.
+ **Type:** **MySQL/Aurora**
+ **Source:** The identifier of the **tutorial-dual-stack-securitygroup** security group that you created previously in this tutorial, for example **sg-9edd5cfb**.
1. To create the security group, choose **Create security group**.
## Create a DB subnet group
A *DB subnet group* is a collection of subnets that you create in a VPC and that you then designate for your DB clusters. By using a DB subnet group, you can specify a particular VPC when creating DB clusters. To create a DB subnet group that is `DUAL` compatible, all subnets must be `DUAL` compatible. To be `DUAL` compatible, a subnet must have an IPv6 CIDR associated with it.
**To create a DB subnet group**
1. Identify the private subnets for your database in the VPC.
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **Subnets**.
1. Note the subnet IDs of the subnets named **tutorial-dual-stack-subnet-private1-us-west-2a** and **tutorial-dual-stack-subnet-private2-us-west-2b**.
You will need the subnet IDs when you create your DB subnet group.
1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
Make sure that you connect to the Amazon RDS console, not to the Amazon VPC console.
1. In the navigation pane, choose **Subnet groups**.
1. Choose **Create DB subnet group**.
1. On the **Create DB subnet group** page, set these values in **Subnet group details**:
+ **Name:** **tutorial-dual-stack-db-subnet-group**
+ **Description:** **Tutorial Dual-Stack DB Subnet Group**
+ **VPC:** **tutorial-dual-stack-vpc (vpc-*identifier*)**
1. In the **Add subnets** section, choose values for the **Availability Zones** and **Subnets** options.
For this tutorial, choose **us-east-2a** and **us-east-2b** for the **Availability Zones**. For **Subnets**, choose the private subnets you identified in the previous step.
1. Choose **Create**.
Your new DB subnet group appears in the DB subnet groups list on the RDS console. You can choose the DB subnet group to see its details. These include the supported addressing protocols and all of the subnets associated with the group and the network type supported by the DB subnet group.
## Create an Amazon EC2 instance in dual-stack mode
To create an Amazon EC2 instance, follow the instructions in [Launch an instance using the new launch instance wizard](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-launch-instance-wizard.html) in the *Amazon EC2 User Guide*.
On the **Configure Instance Details** page, set these values and keep the other values as their defaults:
+ **Network** – Choose an existing VPC with both public and private subnets, such as **tutorial-dual-stack-vpc** (vpc-*identifier*) created in [Create a VPC with private and public subnets](#CHAP_Tutorials.CreateVPCDualStack.VPCAndSubnets).
+ **Subnet** – Choose an existing public subnet, such as **subnet-*identifier* \$1 tutorial-dual-stack-subnet-public1-us-east-2a \$1 us-east-2a** created in [Create a VPC security group for a public Amazon EC2 instance](#CHAP_Tutorials.CreateVPCDualStack.SecurityGroupEC2).
+ **Auto-assign Public IP** – Choose **Enable**.
+ **Auto-assign IPv6 IP** – Choose **Enable**.
+ **Firewall (security groups)** – Choose **Select an existing security group**.
+ **Common security groups** – Choose an existing security group, such as the `tutorial-securitygroup` created in [Create a VPC security group for a public Amazon EC2 instance](#CHAP_Tutorials.CreateVPCDualStack.SecurityGroupEC2). Make sure that the security group that you choose includes inbound rules for Secure Shell (SSH) and HTTP access.
## Create a DB cluster in dual-stack mode
In this step, you create a DB cluster that runs in dual-stack mode.
**To create a DB instance**
1. Sign in to the AWS Management Console and open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the upper-right corner of the console, choose the AWS Region where you want to create the DB cluster. This example uses the US East (Ohio) Region.
1. In the navigation pane, choose **Databases**.
1. Choose **Create database**.
1. On the **Create database** page, make sure that the **Standard create** option is chosen, and then choose the Aurora MySQL DB engine type.
1. In the **Connectivity** section, set these values:
+ **Network type** – Choose **Dual-stack mode**.
![\[Network type section in the console with Dual-stack mode selected\]](http://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/images/dual-stack-mode.png)
+ **Virtual private cloud (VPC)** – Choose an existing VPC with both public and private subnets, such as **tutorial-dual-stack-vpc** (vpc-*identifier*) created in [Create a VPC with private and public subnets](#CHAP_Tutorials.CreateVPCDualStack.VPCAndSubnets).
The VPC must have subnets in different Availability Zones.
+ **DB subnet group** – Choose a DB subnet group for the VPC, such as **tutorial-dual-stack-db-subnet-group** created in [Create a DB subnet group](#CHAP_Tutorials.CreateVPCDualStack.DBSubnetGroup).
+ **Public access** – Choose **No**.
+ **VPC security group (firewall)** – Select **Choose existing**.
+ **Existing VPC security groups** – Choose an existing VPC security group that is configured for private access, such as **tutorial-dual-stack-db-securitygroup** created in [Create a VPC security group for a private DB cluster](#CHAP_Tutorials.CreateVPCDualStack.SecurityGroupDB).
Remove other security groups, such as the default security group, by choosing the **X** associated with each.
+ **Availability Zone** – Choose **us-west-2a**.
To avoid cross-AZ traffic, make sure the DB instance and the EC2 instance are in the same Availability Zone.
1. For the remaining sections, specify your DB cluster settings. For information about each setting, see [Settings for Aurora DB clusters](Aurora.CreateInstance.md#Aurora.CreateInstance.Settings).
## Connect to your Amazon EC2 instance and DB cluster
After you create your Amazon EC2 instance and DB cluster in dual-stack mode, you can connect to each one using the IPv6 protocol. To connect to an Amazon EC2 instance using the IPv6 protocol, follow the instructions in [Connect to your Linux instance](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/AccessingInstances.html) in the *Amazon EC2 User Guide*.
To connect to your Aurora MySQL DB cluster from the Amazon EC2 instance, follow the instructions in [Connect to an Aurora MySQL DB cluster](CHAP_GettingStartedAurora.CreatingConnecting.Aurora.md#CHAP_GettingStartedAurora.Aurora.Connect).
## Deleting the VPC
After you create the VPC and other resources for this tutorial, you can delete them if they are no longer needed.
If you added resources in the VPC that you created for this tutorial, you might need to delete these before you can delete the VPC. Examples of resources are Amazon EC2 instances or DB clusters. For more information, see [Delete your VPC](https://docs.aws.amazon.com/vpc/latest/userguide/working-with-vpcs.html#VPC_Deleting) in the *Amazon VPC User Guide*.
**To delete a VPC and related resources**
1. Delete the DB subnet group:
1. Open the Amazon RDS console at [https://console.aws.amazon.com/rds/](https://console.aws.amazon.com/rds/).
1. In the navigation pane, choose **Subnet groups**.
1. Select the DB subnet group to delete, such as **tutorial-db-subnet-group**.
1. Choose **Delete**, and then choose **Delete** in the confirmation window.
1. Note the VPC ID:
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **VPCs**.
1. In the list, identify the VPC you created, such as **tutorial-dual-stack-vpc**.
1. Note the **VPC ID** value of the VPC that you created. You need this VPC ID in subsequent steps.
1. Delete the security groups:
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **Security Groups**.
1. Select the security group for the Amazon RDS DB instance, such as **tutorial-dual-stack-db-securitygroup**.
1. For **Actions**, choose **Delete security groups**, and then choose **Delete** on the confirmation page.
1. On the **Security Groups** page, select the security group for the Amazon EC2 instance, such as **tutorial-dual-stack-securitygroup**.
1. For **Actions**, choose **Delete security groups**, and then choose **Delete** on the confirmation page.
1. Delete the NAT gateway:
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **NAT Gateways**.
1. Select the NAT gateway of the VPC that you created. Use the VPC ID to identify the correct NAT gateway.
1. For **Actions**, choose **Delete NAT gateway**.
1. On the confirmation page, enter **delete**, and then choose **Delete**.
1. Delete the VPC:
1. Open the Amazon VPC console at [https://console.aws.amazon.com/vpc/](https://console.aws.amazon.com/vpc/).
1. Choose **VPC Dashboard**, and then choose **VPCs**.
1. Select the VPC that you want to delete, such as **tutorial-dual-stack-vpc**.
1. For **Actions**, choose **Delete VPC**.
The confirmation page shows other resources that are associated with the VPC that will also be deleted, including the subnets associated with it.
1. On the confirmation page, enter **delete**, and then choose **Delete**.
1. Release the Elastic IP addresses:
1. Open the Amazon EC2 console at [https://console.aws.amazon.com/ec2/](https://console.aws.amazon.com/ec2/).
1. Choose **EC2 Dashboard**, and then choose **Elastic IPs**.
1. Select the Elastic IP address that you want to release.
1. For **Actions**, choose **Release Elastic IP addresses**.
1. On the confirmation page, choose **Release**.