Enable enhanced networking with ENA on your EC2 instances

Connect to your instance.

From the instance, run the following command to update your instance with the latest kernel drivers, including ena:

[ec2-user ~]$ sudo yum update

From your local computer, reboot your instance using the Amazon EC2 console or one of the following commands: reboot-instances (AWS CLI), Restart-EC2Instance (AWS Tools for Windows PowerShell).

Connect to your instance again and verify that the ena kernel driver is installed and at the minimum recommended version using the modinfo ena command from Test whether enhanced networking is enabled.

[EBS-backed instance] From your local computer, stop the instance using the Amazon EC2 console or one of the following commands: stop-instances (AWS CLI), Stop-EC2Instance (AWS Tools for Windows PowerShell).

[Instance store-backed instance] You can't stop the instance to modify the attribute. Instead, proceed to this procedure: To enable enhanced networking on Amazon Linux AMI (instance store-backed instances).

From your local computer, enable the enhanced networking attribute using one of the following commands:

(Optional) Create an AMI from the instance, as described in Create an Amazon EBS-backed AMI. The AMI inherits the enhanced networking enaSupport attribute from the instance. Therefore, you can use this AMI to launch another instance with enhanced networking enabled by default.

From your local computer, start the instance using the Amazon EC2 console or one of the following commands: start-instances (AWS CLI), Start-EC2Instance (AWS Tools for Windows PowerShell).

Connect to your instance and verify that the ena kernel driver is installed and loaded on your network interface using the ethtool -i ethn command from Test whether enhanced networking is enabled.

If you are unable to connect to your instance after enabling enhanced networking, see Troubleshoot the ENA kernel driver on Linux.

Connect to your instance.

Update the package cache and packages.

ubuntu:~$ sudo apt-get update && sudo apt-get upgrade -y linux-aws

[EBS-backed instance] From your local computer, stop the instance using the Amazon EC2 console or one of the following commands: stop-instances (AWS CLI), Stop-EC2Instance (AWS Tools for Windows PowerShell).

[Instance store-backed instance] You can't stop the instance to modify the attribute. Instead, proceed to this procedure: To enable enhanced networking on Ubuntu (instance store-backed instances).

From your local computer, enable the enhanced networking attribute using one of the following commands:

(Optional) Create an AMI from the instance, as described in Create an Amazon EBS-backed AMI. The AMI inherits the enhanced networking enaSupport attribute from the instance. Therefore, you can use this AMI to launch another instance with enhanced networking enabled by default.

From your local computer, start the instance using the Amazon EC2 console or one of the following commands: start-instances (AWS CLI), Start-EC2Instance (AWS Tools for Windows PowerShell).

Connect to your instance.

Clone the source code for the ena kernel driver on your instance from GitHub at https://github.com/amzn/amzn-drivers. (SUSE Linux Enterprise Server 12 SP2 and later include ENA 2.02 by default, so you are not required to download and compile the ENA driver. For SUSE Linux Enterprise Server 12 SP2 and later, you should file a request to add the driver version you want to the stock kernel).

git clone https://github.com/amzn/amzn-drivers

Compile and install the ena kernel driver on your instance. These steps depend on the Linux distribution. For more information about compiling the kernel driver on Red Hat Enterprise Linux, see How do I install the latest ENS driver for enhanced network support on an Amazon EC2 instance that runs RHEL?

Run the sudo depmod command to update kernel driver dependencies.

Update initramfs on your instance to ensure that the new kernel driver loads at boot time. For example, if your distribution supports dracut, you can use the following command.

dracut -f -v

Determine if your system uses predictable network interface names by default. Systems that use systemd or udev versions 197 or greater can rename Ethernet devices and they do not guarantee that a single network interface will be named eth0. This behavior can cause problems connecting to your instance. For more information and to see other configuration options, see Predictable Network Interface Names on the freedesktop.org website.

1. You can check the systemd or udev versions on RPM-based systems with the following command.

   rpm -qa | grep -e '^systemd-[0-9]\+\|^udev-[0-9]\+'
   systemd-208-11.el7_0.2.x86_64

   In the above Red Hat Enterprise Linux 7 example, the systemd version is 208, so predictable network interface names must be disabled.

2. Disable predictable network interface names by adding the net.ifnames=0 option to the GRUB_CMDLINE_LINUX line in /etc/default/grub.

   sudo sed -i '/^GRUB\_CMDLINE\_LINUX/s/\"$/\ net\.ifnames\=0\"/' /etc/default/grub

3. Rebuild the grub configuration file.

   sudo grub2-mkconfig -o /boot/grub2/grub.cfg

[EBS-backed instance] From your local computer, stop the instance using the Amazon EC2 console or one of the following commands: stop-instances (AWS CLI), Stop-EC2Instance (AWS Tools for Windows PowerShell).

[Instance store-backed instance] You can't stop the instance to modify the attribute. Instead, proceed to this procedure: To enable enhanced networking on Linux (instance store–backed instances).

From your local computer, enable the enhanced networking enaSupport attribute using one of the following commands:

(Optional) Create an AMI from the instance, as described in Create an Amazon EBS-backed AMI. The AMI inherits the enhanced networking enaSupport attribute from the instance. Therefore, you can use this AMI to launch another instance with enhanced networking enabled by default.

If your instance operating system contains an /etc/udev/rules.d/70-persistent-net.rules file, you must delete it before creating the AMI. This file contains the MAC address for the Ethernet adapter of the original instance. If another instance boots with this file, the operating system will be unable to find the device and eth0 might fail, causing boot issues. This file is regenerated at the next boot cycle, and any instances launched from the AMI create their own version of the file.

From your local computer, start the instance using the Amazon EC2 console or one of the following commands: start-instances (AWS CLI), Start-EC2Instance (AWS Tools for Windows PowerShell).

(Optional) Connect to your instance and verify that the kernel driver is installed.

If you are unable to connect to your instance after enabling enhanced networking, see Troubleshoot the ENA kernel driver on Linux.

Follow steps 1 and 2 in Ubuntu.

Install the build-essential packages to compile the kernel driver and the dkms package so that your ena kernel driver is rebuilt every time your kernel is updated.

ubuntu:~$ sudo apt-get install -y build-essential dkms

Clone the source for the ena kernel driver on your instance from GitHub at https://github.com/amzn/amzn-drivers.

ubuntu:~$ git clone https://github.com/amzn/amzn-drivers

Move the amzn-drivers package to the /usr/src/ directory so DKMS can find it and build it for each kernel update. Append the version number (you can find the current version number in the release notes) of the source code to the directory name. For example, version 1.0.0 is shown in the following example.

ubuntu:~$ sudo mv amzn-drivers /usr/src/amzn-drivers-1.0.0

Create the DKMS configuration file with the following values, substituting your version of ena.

Create the file.

ubuntu:~$ sudo touch /usr/src/amzn-drivers-1.0.0/dkms.conf

Edit the file and add the following values.

ubuntu:~$ sudo vim /usr/src/amzn-drivers-1.0.0/dkms.conf
PACKAGE_NAME="ena"
PACKAGE_VERSION="1.0.0"
CLEAN="make -C kernel/linux/ena clean"
MAKE="make -C kernel/linux/ena/ BUILD_KERNEL=${kernelver}"
BUILT_MODULE_NAME[0]="ena"
BUILT_MODULE_LOCATION="kernel/linux/ena"
DEST_MODULE_LOCATION[0]="/updates"
DEST_MODULE_NAME[0]="ena"
AUTOINSTALL="yes"

Add, build, and install the ena kernel driver on your instance using DKMS.

Add the kernel driver to DKMS.

ubuntu:~$ sudo dkms add -m amzn-drivers -v 1.0.0

Build the kernel driver using the dkms command.

ubuntu:~$ sudo dkms build -m amzn-drivers -v 1.0.0

Install the kernel driver using dkms.

ubuntu:~$ sudo dkms install -m amzn-drivers -v 1.0.0

Rebuild initramfs so the correct kernel driver is loaded at boot time.

ubuntu:~$ sudo update-initramfs -u -k all

Verify that the ena kernel driver is installed using the modinfo ena command from Test whether enhanced networking is enabled.

ubuntu:~$ modinfo ena
filename:	   /lib/modules/3.13.0-74-generic/updates/dkms/ena.ko
version:		1.0.0
license:		GPL
description:	Elastic Network Adapter (ENA)
author:		 Amazon.com, Inc. or its affiliates
srcversion:	 9693C876C54CA64AE48F0CA
alias:		  pci:v00001D0Fd0000EC21sv*sd*bc*sc*i*
alias:		  pci:v00001D0Fd0000EC20sv*sd*bc*sc*i*
alias:		  pci:v00001D0Fd00001EC2sv*sd*bc*sc*i*
alias:		  pci:v00001D0Fd00000EC2sv*sd*bc*sc*i*
depends:
vermagic:	   3.13.0-74-generic SMP mod_unload modversions
parm:		   debug:Debug level (0=none,...,16=all) (int)
parm:		   push_mode:Descriptor / header push mode (0=automatic,1=disable,3=enable)
		  0 - Automatically choose according to device capability (default)
		  1 - Don't push anything to device memory
		  3 - Push descriptors and header buffer to device memory (int)
parm:		   enable_wd:Enable keepalive watchdog (0=disable,1=enable,default=1) (int)
parm:		   enable_missing_tx_detection:Enable missing Tx completions. (default=1) (int)
parm:		   numa_node_override_array:Numa node override map
(array of int)
parm:		   numa_node_override:Enable/Disable numa node override (0=disable)
(int)

Continue with Step 3 in Ubuntu.

Connect to your instance and log in as the local administrator.

[Windows Server 2016 and 2019 only] Run the following EC2Launch PowerShell script to configure the instance after the driver is installed.

PS C:\> C:\ProgramData\Amazon\EC2-Windows\Launch\Scripts\InitializeInstance.ps1 -Schedule

From the instance, install the driver as follows:

1. Download the latest driver to the instance.

2. Extract the zip archive.

3. Install the driver by running the install.ps1 PowerShell script.

   Note

   If you get an execution policy error, set the policy to Unrestricted (by default it is set to Restricted or RemoteSigned). In a command line, run Set-ExecutionPolicy -ExecutionPolicy Unrestricted, and then run the install.ps1 PowerShell script again.

From your local computer, stop the instance using the Amazon EC2 console or one of the following commands: stop-instances (AWS CLI/AWS CloudShell), Stop-EC2Instance (AWS Tools for Windows PowerShell).

Enable ENA support on your instance as follows:

1. From your local computer, check the EC2 instance ENA support attribute on your instance by running one of the following commands. If the attribute is not enabled, the output will be "[]" or blank. EnaSupport is set to false by default.

   • describe-instances (AWS CLI/AWS CloudShell)

     aws ec2 describe-instances --instance-ids instance_id --query "Reservations[].Instances[].EnaSupport"

   • Get-EC2Instance (Tools for Windows PowerShell)

     (Get-EC2Instance -InstanceId instance-id).Instances.EnaSupport

2. To enable ENA support, run one of the following commands:

   • modify-instance-attribute (AWS CLI/AWS CloudShell)

     aws ec2 modify-instance-attribute --instance-id instance_id --ena-support

   • Edit-EC2InstanceAttribute (AWS Tools for Windows PowerShell)

     Edit-EC2InstanceAttribute -InstanceId instance_id -EnaSupport $true

   If you encounter problems when you restart the instance, you can also disable ENA support using one of the following commands:

   • modify-instance-attribute (AWS CLI/AWS CloudShell)

     aws ec2 modify-instance-attribute --instance-id instance_id --no-ena-support

   • Edit-EC2InstanceAttribute (AWS Tools for Windows PowerShell)

     Edit-EC2InstanceAttribute -InstanceId instance_id -EnaSupport $false

3. Verify that the attribute has been set to true using describe-instances or Get-EC2Instance as shown previously. You should now see the following output:

   [
   	true
   ]

From your local computer, start the instance using the Amazon EC2 console or one of the following commands: start-instances (AWS CLI/AWS CloudShell), Start-EC2Instance (AWS Tools for Windows PowerShell).

On the instance, validate that the ENA driver is installed and enabled as follows:

1. Right-click the network icon and choose Open Network and Sharing Center.

2. Choose the Ethernet adapter (for example, Ethernet 2).

3. Choose Details. For Network Connection Details, check that Description is Amazon Elastic Network Adapter.

(Optional) Create an AMI from the instance. The AMI inherits the enaSupport attribute from the instance. Therefore, you can use this AMI to launch another instance with ENA enabled by default.