# MemoryDB and Amazon VPC The Amazon Virtual Private Cloud (Amazon VPC) service defines a virtual network that closely resembles a traditional data center. When you configure a virtual private cloud (VPC) with Amazon VPC, you can select its IP address range, create subnets, and configure route tables, network gateways, and security settings. You can also add a cluster to the virtual network, and control access to the cluster by using Amazon VPC security groups. This section explains how to manually configure a MemoryDB cluster in a VPC. This information is intended for users who want a deeper understanding of how MemoryDB and Amazon VPC work together. **Topics** + [ # Understanding MemoryDB and VPCs ](vpcs.mdb.md) + [ # Access Patterns for Accessing a MemoryDB Cluster in an Amazon VPC ](memorydb-vpc-accessing.md) + [ # Creating a Virtual Private Cloud (VPC) ](VPCs.creatingVPC.md) # Understanding MemoryDB and VPCs MemoryDB is fully integrated with Amazon VPC. For MemoryDB users, this means the following: + MemoryDB always launches your cluster in a VPC. + If you're new to AWS, a default VPC will be created for you automatically. + If you have a default VPC and don't specify a subnet when you launch a cluster, the cluster launches into your default Amazon VPC. For more information, see [Detecting Your Supported Platforms and Whether You Have a Default VPC](https://docs.aws.amazon.com/vpc/latest/userguide/default-vpc.html#detecting-platform). With Amazon VPC, you can create a virtual network in the AWS Cloud that closely resembles a traditional data center. You can configure your VPC, including selecting its IP address range, creating subnets, and configuring route tables, network gateways, and security settings. MemoryDB manages software upgrades, patching, failure detection, and recovery. ## Overview of MemoryDB in a VPC + A VPC is an isolated portion of the AWS Cloud that is assigned its own block of IP addresses. + An internet gateway connects your VPC directly to the internet and provides access to other AWS resources such as Amazon Simple Storage Service (Amazon S3) that are running outside your VPC. + An Amazon VPC subnet is a segment of the IP address range of a VPC where you can isolate AWS resources according to your security and operational needs. + An Amazon VPC security group controls inbound and outbound traffic for your MemoryDB clusters and Amazon EC2 instances. + You can launch a MemoryDB cluster in the subnet. The nodes have private IP addresses from the subnet's range of addresses. + You can also launch Amazon EC2 instances in the subnet. Each Amazon EC2 instance has a private IP address from the subnet's range of addresses. The Amazon EC2 instance can connect to any node in the same subnet. + For an Amazon EC2 instance in your VPC to be reachable from the internet, you need to assign a static, public address called a Elastic IP address to the instance. ## Prerequisites To create a MemoryDB cluster within a VPC, your VPC must meet the following requirements: + Your VPC must allow nondedicated Amazon EC2 instances. You cannot use MemoryDB in a VPC that is configured for dedicated instance tenancy. + A subnet group must be defined for your VPC. MemoryDB uses that subnet group to select a subnet and IP addresses within that subnet to associate with your nodes. + A security group must be defined for your VPC, or you can use the default provided. + CIDR blocks for each subnet must be large enough to provide spare IP addresses for MemoryDB to use during maintenance activities. ## Routing and security You can configure routing in your VPC to control where traffic flows (for example, to the internet gateway or virtual private gateway). With an internet gateway, your VPC has direct access to other AWS resources that are not running in your VPC. If you choose to have only a virtual private gateway with a connection to your organization's local network, you can route your internet-bound traffic over the VPN and use local security policies and firewall to control egress. In that case, you incur additional bandwidth charges when you access AWS resources over the internet. You can use Amazon VPC security groups to help secure the MemoryDB clusters and Amazon EC2 instances in your Amazon VPC. Security groups act like a firewall at the instance level, not the subnet level. **Note** We strongly recommend that you use DNS names to connect to your nodes, as the underlying IP address can change over time. ## Amazon VPC documentation Amazon VPC has its own set of documentation to describe how to create and use your Amazon VPC. The following table shows where to find information in the Amazon VPC guides. | Description | Documentation | | --- | --- | | How to get started using Amazon VPC | [Getting started with Amazon VPC](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-getting-started.html) | | How to use Amazon VPC through the AWS Management Console | [Amazon VPC User Guide](https://docs.aws.amazon.com/vpc/latest/userguide/) | | Complete descriptions of all the Amazon VPC commands | [Amazon EC2 Command Line Reference](https://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/) (the Amazon VPC commands are found in the Amazon EC2 reference) | | Complete descriptions of the Amazon VPC API operations, data types, and errors | [Amazon EC2 API Reference](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/) (the Amazon VPC API operations are found in the Amazon EC2 reference) | | Information for the network administrator who needs to configure the gateway at your end of an optional IPsec VPN connection | [What is AWS Site-to-Site VPN?](https://docs.aws.amazon.com/vpn/latest/s2svpn/VPC_VPN.html) | For more detailed information about Amazon Virtual Private Cloud, see [Amazon Virtual Private Cloud](https://aws.amazon.com/vpc/). # Access Patterns for Accessing a MemoryDB Cluster in an Amazon VPC MemoryDB supports the following scenarios for accessing a cluster in an Amazon VPC: **Contents** + [ ## Accessing a MemoryDB Cluster when it and the Amazon EC2 Instance are in the Same Amazon VPC ](#memorydb-vpc-accessing-same-vpc) + [ ## Accessing a MemoryDB Cluster when it and the Amazon EC2 Instance are in Different Amazon VPCs ](#memorydb-vpc-accessing-different-vpc) + [In Different Amazon VPCs in the Same Region](#memorydb-vpc-accessing-different-vpc-same-region) + [Using Transit Gateway](#memorydb-vpc-accessing-using-transit-gateway) + [In Different Amazon VPCs in Different Regions](#memorydb-vpc-accessing-different-vpc-different-region) + [Using Transit VPC](#memorydb-vpc-accessing-different-vpc-different-region-using-transit-vpc) + [ ## Accessing a MemoryDB Cluster from an Application Running in a Customer's Data Center ](#memorydb-vpc-accessing-data-center) + [Using VPN Connectivity](#memorydb-vpc-accessing-data-center-vpn) + [Using Direct Connect](#memorydb-vpc-accessing-data-center-direct-connect) ## Accessing a MemoryDB Cluster when it and the Amazon EC2 Instance are in the Same Amazon VPC The most common use case is when an application deployed on an EC2 instance needs to connect to a cluster in the same VPC. The simplest way to manage access between EC2 instances and clusters in the same VPC is to do the following: 1. Create a VPC security group for your cluster. This security group can be used to restrict access to the clusters. For example, you can create a custom rule for this security group that allows TCP access using the port you assigned to the cluster when you created it and an IP address you will use to access the cluster. The default port for MemoryDB clusters is `6379`. 1. Create a VPC security group for your EC2 instances (web and application servers). This security group can, if needed, allow access to the EC2 instance from the Internet via 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. 1. Create custom rules in the security group for your cluster that allow connections from the security group you created for your EC2 instances. This would allow any member of the security group to access the clusters. **To create a rule in a VPC security group that allows connections from another security group** 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 left navigation pane, choose **Security Groups**. 1. Select or create a security group that you will use for your clusters. Under **Inbound Rules**, select **Edit Inbound Rules** and then select **Add Rule**. This security group will allow access to members of another security group. 1. From **Type** choose **Custom TCP Rule**. 1. For **Port Range**, specify the port you used when you created your cluster. The default port for MemoryDB clusters is `6379`. 1. In the **Source** box, start typing the ID of the security group. From the list select the security group you will use for your Amazon EC2 instances. 1. Choose **Save** when you finish. ## Accessing a MemoryDB Cluster when it and the Amazon EC2 Instance are in Different Amazon VPCs When your cluster is in a different VPC from the EC2 instance you are using to access it, there are several ways to access the cluster. If the cluster and EC2 instance are in different VPCs but in the same region, you can use VPC peering. If the cluster and the EC2 instance are in different regions, you can create VPN connectivity between regions. **Topics** + [In Different Amazon VPCs in the Same Region](#memorydb-vpc-accessing-different-vpc-same-region) + [In Different Amazon VPCs in Different Regions](#memorydb-vpc-accessing-different-vpc-different-region)   ### Accessing a MemoryDB Cluster when it and the Amazon EC2 Instance are in Different Amazon VPCs in the Same Region *Cluster accessed by an Amazon EC2 instance in a different Amazon VPC within the same Region - VPC Peering Connection* A VPC peering connection is a networking connection between two VPCs that enables you to route traffic between them using private IP addresses. Instances 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 Amazon VPCs, or with an Amazon VPC in another AWS account within a single region. To learn more about Amazon VPC peering, see the [VPC documentation](http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/vpc-peering.html). **To access a cluster in a different Amazon VPC over peering** 1. Make sure that the two VPCs do not have an overlapping IP range or you will not be able to peer them. 1. Peer the two VPCs. For more information, see [Creating and Accepting an Amazon VPC Peering Connection](http://docs.aws.amazon.com/AmazonVPC/latest/PeeringGuide/create-vpc-peering-connection.html). 1. Update your routing table. For more information, see [Updating Your Route Tables for a VPC Peering Connection](http://docs.aws.amazon.com/AmazonVPC/latest/PeeringGuide/vpc-peering-routing.html) 1. Modify the Security Group of your MemoryDB cluster to allow inbound connection from the Application security group in the peered VPC. For more information, see [Reference Peer VPC Security Groups](http://docs.aws.amazon.com/AmazonVPC/latest/PeeringGuide/vpc-peering-security-groups.html). Accessing a cluster over a peering connection will incur additional data transfer costs.   #### Using Transit Gateway A transit gateway enables you to attach VPCs and VPN connections in the same AWS Region and route traffic between them. A transit gateway works across AWS accounts, and you can use AWS Resource Access Manager to share your transit gateway with other accounts. After you share a transit gateway with another AWS account, the account owner can attach their VPCs to your transit gateway. A user from either account can delete the attachment at any time. You can enable multicast on a transit gateway, and then create a transit gateway multicast domain that allows multicast traffic to be sent from your multicast source to multicast group members over VPC attachments that you associate with the domain. You can also create a peering connection attachment between transit gateways in different AWS Regions. This enables you to route traffic between the transit gateways' attachments across different Regions. For more information, see [Transit gateways](https://docs.aws.amazon.com/vpc/latest/tgw/tgw-transit-gateways.html). ### Accessing a MemoryDB Cluster when it and the Amazon EC2 Instance are in Different Amazon VPCs in Different Regions #### Using Transit VPC An alternative to using VPC peering, another common strategy for connecting multiple, geographically disperse VPCs and remote networks is to create a transit VPC that serves as a global network transit center. A transit VPC simplifies network management and minimizes the number of connections required to connect multiple VPCs and remote networks. This design can save time and effort and also reduce costs, as it is implemented virtually without the traditional expense of establishing a physical presence in a colocation transit hub or deploying physical network gear. *Connecting across different VPCs in different regions* Once the Transit Amazon VPC is established, an application deployed in a “spoke” VPC in one region can connect to a MemoryDB cluster in a “spoke” VPC within another region. **To access a cluster in a different VPC within a different AWS Region** 1. Deploy a Transit VPC Solution. For more information, see, [AWSTransit Gateway](https://aws.amazon.com/transit-gateway/). 1. Update the VPC routing tables in the App and VPCs to route traffic through the VGW (Virtual Private Gateway) and the VPN Appliance. In case of Dynamic Routing with Border Gateway Protocol (BGP) your routes may be automatically propagated. 1. Modify the Security Group of your MemoryDB cluster to allow inbound connection from the Application instances IP range. Note that you will not be able to reference the application server Security Group in this scenario. Accessing a cluster across regions will introduce networking latencies and additional cross-region data transfer costs. ## Accessing a MemoryDB Cluster from an Application Running in a Customer's Data Center Another possible scenario is a Hybrid architecture where clients or applications in the customer’s data center may need to access a MemoryDB Cluster in the VPC. This scenario is also supported providing there is connectivity between the customers’ VPC and the data center either through VPN or Direct Connect. **Topics** + [Using VPN Connectivity](#memorydb-vpc-accessing-data-center-vpn) + [Using Direct Connect](#memorydb-vpc-accessing-data-center-direct-connect)   ### Accessing a MemoryDB Cluster from an Application Running in a Customer's Data Center Using VPN Connectivity *Connecting to MemoryDB from your data center via a VPN* **To access a cluster in a VPC from on-prem application over VPN connection** 1. Establish VPN Connectivity by adding a hardware Virtual Private Gateway to your VPC. For more information, see [Adding a Hardware Virtual Private Gateway to Your VPC](http://docs.aws.amazon.com/AmazonVPC/latest/UserGuide/VPC_VPN.html). 1. Update the VPC routing table for the subnet where your MemoryDB cluster is deployed to allow traffic from your on-premises application server. In case of Dynamic Routing with BGP your routes may be automatically propagated. 1. Modify the Security Group of your MemoryDB cluster to allow inbound connection from the on-premises application servers. Accessing a cluster over a VPN connection will introduce networking latencies and additional data transfer costs.   ### Accessing a MemoryDB Cluster from an Application Running in a Customer's Data Center Using Direct Connect *Connecting to MemoryDB from your data center via Direct Connect* **To access a MemoryDB cluster from an application running in your network using Direct Connect** 1. Establish Direct Connect connectivity. For more information, see, [Getting Started with AWS Direct Connect](http://docs.aws.amazon.com/directconnect/latest/UserGuide/getting_started.html). 1. Modify the Security Group of your MemoryDB cluster to allow inbound connection from the on-premises application servers. Accessing a cluster over DX connection may introduce networking latencies and additional data transfer charges. # Creating a Virtual Private Cloud (VPC) In this example, you create a virtual private cloud (VPC) based on the Amazon VPC service with a private subnet for each Availability Zone. ## Creating a VPC (Console) **To create a MemoryDB cluster inside an Amazon Virtual Private Cloud** 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 VPC dashboard, choose **Create VPC**. 1. Under **Resources** to create, choose **VPC and more**. 1. Under **Number of Availability Zones (AZs)**, choose the number of Availability Zones you want to launch your subnets in. 1. Under **Number of public subnets**, choose the number of public subnets you want to add to your VPC. 1. Under **Number of private subnets**, choose the number of private subnets you want to add to your VPC. **Tip** Make a note of your subnet identifiers, and which are public and private. You will need this information later when you launch your clusters and add an Amazon EC2 instance to your Amazon VPC. 1. Create an Amazon VPC security group. You will use this group for your cluster and your Amazon EC2 instance. 1. In the left navigation pane of the AWS Management Console, choose **Security Groups**. 1. Choose **Create Security Group**. 1. Enter a name and a description for your security group in the corresponding boxes. For **VPC**, choose the identifier for your VPC. 1. When the settings are as you want them, choose **Yes, Create**. 1. Define a network ingress rule for your security group. This rule will allow you to connect to your Amazon EC2 instance using Secure Shell (SSH). 1. In the left navigation pane, choose **Security Groups**. 1. Find your security group in the list, and then choose it. 1. Under **Security Group**, choose the **Inbound** tab. In the **Create a new rule** box, choose **SSH**, and then choose **Add Rule**. Set the following values for your new inbound rule to allow HTTP access: + Type: HTTP + Source: 0.0.0.0/0 1. Set the following values for your new inbound rule to allow HTTP access: + Type: HTTP + Source: 0.0.0.0/0 Choose **Apply Rule Changes**. Now you are ready to create a [ subnet group](https://docs.aws.amazon.com/memorydb/latest/devguide/subnetgroups.html) and [create a cluster](https://docs.aws.amazon.com/memorydb/latest/devguide/getting-started.createcluster.html) in your VPC.