Enable enhanced networking with the Elastic Network Adapter (ENA) on Linux instances - Amazon Elastic Compute Cloud

Enable enhanced networking with the Elastic Network Adapter (ENA) on Linux instances

Amazon EC2 provides enhanced networking capabilities through the Elastic Network Adapter (ENA). To use enhanced networking, you must install the required ENA module and enable ENA support.

Requirements

To prepare for enhanced networking using the ENA, set up your instance as follows:

  • Launch an instance based on the Nitro system.

  • Launch the instance using a supported version of the Linux kernel and a supported distribution, so that ENA enhanced networking is enabled for your instance automatically. For more information, see ENA Linux Kernel Driver Release Notes.

  • Ensure that the instance has internet connectivity.

  • Use AWS CloudShell from the AWS Management Console, or install and configure the AWS CLI or the AWS Tools for Windows PowerShell on any computer you choose, preferably your local desktop or laptop. For more information, see Access Amazon EC2 or the AWS CloudShell User Guide. Enhanced networking cannot be managed from the Amazon EC2 console.

  • If you have important data on the instance that you want to preserve, you should back that data up now by creating an AMI from your instance. Updating kernels and kernel modules, as well as enabling the enaSupport attribute, might render incompatible instances or operating systems unreachable. If you have a recent backup, your data will still be retained if this happens.

Enhanced networking performance

The following documentation provides a summary of the network performance for the instance types that support ENA enhanced networking:

Test whether enhanced networking is enabled

The following AMIs include the required ENA module and have ENA support enabled:

  • AL2023

  • Amazon Linux 2

  • Amazon Linux AMI 2018.03 and later

  • Ubuntu 14.04 or later with linux-aws kernel

    Note

    AWS Graviton-based instance types require Ubuntu 18.04 or later with linux-aws kernel

  • Red Hat Enterprise Linux 7.4 or later

  • SUSE Linux Enterprise Server 12 SP2 or later

  • CentOS 7.4.1708 or later

  • FreeBSD 11.1 or later

  • Debian GNU/Linux 9 or later

To test whether enhanced networking is already enabled, verify that the ena module is installed on your instance and that the enaSupport attribute is set. If your instance satisfies these two conditions, then the ethtool -i ethn command should show that the module is in use on the network interface.

Kernel module (ena)

To verify that the ena module is installed, use the modinfo command as shown in the following example.

[ec2-user ~]$ modinfo ena filename: /lib/modules/4.14.33-59.37.amzn2.x86_64/kernel/drivers/amazon/net/ena/ena.ko version: 1.5.0g license: GPL description: Elastic Network Adapter (ENA) author: Amazon.com, Inc. or its affiliates srcversion: 692C7C68B8A9001CB3F31D0 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: retpoline: Y intree: Y name: ena ...

In the above Amazon Linux case, the ena module is installed.

ubuntu:~$ modinfo ena ERROR: modinfo: could not find module ena

In the above Ubuntu instance, the module is not installed, so you must first install it. For more information, see Enable enhanced networking on Ubuntu.

Instance attribute (enaSupport)

To check whether an instance has the enhanced networking enaSupport attribute set, use one of the following commands. If the attribute is set, the response is true.

  • 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
Image attribute (enaSupport)

To check whether an AMI has the enhanced networking enaSupport attribute set, use one of the following commands. If the attribute is set, the response is true.

  • describe-images (AWS CLI/AWS CloudShell)

    aws ec2 describe-images --image-id ami_id --query "Images[].EnaSupport"
  • Get-EC2Image (Tools for Windows PowerShell)

    (Get-EC2Image -ImageId ami_id).EnaSupport
Network interface driver

Use the following command to verify that the ena module is being used on a particular interface, substituting the interface name that you want to check. If you are using a single interface (default), it this is eth0. If the operating system supports predictable network names, this could be a name like ens5.

In the following example, the ena module is not loaded, because the listed driver is vif.

[ec2-user ~]$ ethtool -i eth0 driver: vif version: firmware-version: bus-info: vif-0 supports-statistics: yes supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no

In this example, the ena module is loaded and at the minimum recommended version. This instance has enhanced networking properly configured.

[ec2-user ~]$ ethtool -i eth0 driver: ena version: 1.5.0g firmware-version: expansion-rom-version: bus-info: 0000:00:05.0 supports-statistics: yes supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no

Enable enhanced networking on the Amazon Linux AMI

Amazon Linux 2 and the latest versions of the Amazon Linux AMI include the module required for enhanced networking with ENA installed and have ENA support enabled. Therefore, if you launch an instance with an HVM version of Amazon Linux on a supported instance type, enhanced networking is already enabled for your instance. For more information, see Test whether enhanced networking is enabled.

If you launched your instance using an older Amazon Linux AMI and it does not have enhanced networking enabled already, use the following procedure to enable enhanced networking.

To enable enhanced networking on Amazon Linux AMI
  1. Connect to your instance.

  2. From the instance, run the following command to update your instance with the newest kernel and kernel modules, including ena:

    [ec2-user ~]$ sudo yum update
  3. 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).

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

  5. [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). If your instance is managed by AWS OpsWorks, you should stop the instance in the AWS OpsWorks console so that the instance state remains in sync.

    [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).

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

  7. (Optional) Create an AMI from the instance, as described in Create an Amazon EBS-backed Linux 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.

  8. 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). If your instance is managed by AWS OpsWorks, you should start the instance in the AWS OpsWorks console so that the instance state remains in sync.

  9. Connect to your instance and verify that the ena module 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 Elastic Network Adapter (ENA).

To enable enhanced networking on Amazon Linux AMI (instance store-backed instances)

Follow the previous procedure until the step where you stop the instance. Create a new AMI as described in Create an instance store-backed Linux AMI, making sure to enable the enhanced networking attribute when you register the AMI.

  • register-image (AWS CLI)

    aws ec2 register-image --ena-support ...
  • Register-EC2Image (AWS Tools for Windows PowerShell)

    Register-EC2Image -EnaSupport $true ...

Enable enhanced networking on Ubuntu

The latest Ubuntu HVM AMIs include the module required for enhanced networking with ENA installed and have ENA support enabled. Therefore, if you launch an instance with the latest Ubuntu HVM AMI on a supported instance type, enhanced networking is already enabled for your instance. For more information, see Test whether enhanced networking is enabled.

If you launched your instance using an older AMI and it does not have enhanced networking enabled already, you can install the linux-aws kernel package to get the latest enhanced networking drivers and update the required attribute.

To install the linux-aws kernel package (Ubuntu 16.04 or later)

Ubuntu 16.04 and 18.04 ship with the Ubuntu custom kernel (linux-aws kernel package). To use a different kernel, contact AWS Support.

To install the linux-aws kernel package (Ubuntu Trusty 14.04)
  1. Connect to your instance.

  2. Update the package cache and packages.

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

    If during the update process you are prompted to install grub, use /dev/xvda to install grub onto, and then choose to keep the current version of /boot/grub/menu.lst.

  3. [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). If your instance is managed by AWS OpsWorks, you should stop the instance in the AWS OpsWorks console so that the instance state remains in sync.

    [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).

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

  5. (Optional) Create an AMI from the instance, as described in Create an Amazon EBS-backed Linux 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.

  6. 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). If your instance is managed by AWS OpsWorks, you should start the instance in the AWS OpsWorks console so that the instance state remains in sync.

To enable enhanced networking on Ubuntu (instance store-backed instances)

Follow the previous procedure until the step where you stop the instance. Create a new AMI as described in Create an instance store-backed Linux AMI, making sure to enable the enhanced networking attribute when you register the AMI.

  • register-image (AWS CLI)

    aws ec2 register-image --ena-support ...
  • Register-EC2Image (AWS Tools for Windows PowerShell)

    Register-EC2Image -EnaSupport $true ...

Enable enhanced networking on Linux

The latest AMIs for Red Hat Enterprise Linux, SUSE Linux Enterprise Server, and CentOS include the module required for enhanced networking with ENA and have ENA support enabled. Therefore, if you launch an instance with the latest AMI on a supported instance type, enhanced networking is already enabled for your instance. For more information, see Test whether enhanced networking is enabled.

The following procedure provides the general steps for enabling enhanced networking on a Linux distribution other than Amazon Linux AMI or Ubuntu. For more information, such as detailed syntax for commands, file locations, or package and tool support, see the documentation for your Linux distribution.

To enable enhanced networking on Linux
  1. Connect to your instance.

  2. Clone the source code for the ena module 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
  3. Compile and install the ena module on your instance. These steps depend on the Linux distribution. For more information about compiling the module on Red Hat Enterprise Linux, see the AWS Knowledge Center article.

  4. Run the sudo depmod command to update module dependencies.

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

    dracut -f -v
  6. 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
  7. [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). If your instance is managed by AWS OpsWorks, you should stop the instance in the AWS OpsWorks console so that the instance state remains in sync.

    [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).

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

  9. (Optional) Create an AMI from the instance, as described in Create an Amazon EBS-backed Linux 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.

    Important

    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.

  10. 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). If your instance is managed by AWS OpsWorks, you should start the instance in the AWS OpsWorks console so that the instance state remains in sync.

  11. (Optional) Connect to your instance and verify that the module is installed.

    If you are unable to connect to your instance after enabling enhanced networking, see Troubleshoot the Elastic Network Adapter (ENA).

To enable enhanced networking on Linux (instance store–backed instances)

Follow the previous procedure until the step where you stop the instance. Create a new AMI as described in Create an instance store-backed Linux AMI, making sure to enable the enhanced networking attribute when you register the AMI.

Enable enhanced networking on Ubuntu with DKMS

This method is for testing and feedback purposes only. It is not intended for use with production deployments. For production deployments, see Enable enhanced networking on Ubuntu.

Important

Using DKMS voids the support agreement for your subscription. It should not be used for production deployments.

To enable enhanced networking with ENA on Ubuntu (EBS-backed instances)
  1. Follow steps 1 and 2 in Enable enhanced networking on Ubuntu.

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

    ubuntu:~$ sudo apt-get install -y build-essential dkms
  3. Clone the source for the ena module on your instance from GitHub at https://github.com/amzn/amzn-drivers.

    ubuntu:~$ git clone https://github.com/amzn/amzn-drivers
  4. 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
  5. 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"
  6. Add, build, and install the ena module on your instance using DKMS.

    Add the module to DKMS.

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

    Build the module using the dkms command.

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

    Install the module using dkms.

    ubuntu:~$ sudo dkms install -m amzn-drivers -v 1.0.0
  7. Rebuild initramfs so the correct module is loaded at boot time.

    ubuntu:~$ sudo update-initramfs -u -k all
  8. Verify that the ena module 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)
  9. Continue with Step 3 in Enable enhanced networking on Ubuntu.

Driver release notes

For information about the versions of the Linux ENA driver, see the ENA Linux kernel driver release notes.

Troubleshoot

For troubleshooting information, see Troubleshoot the Elastic Network Adapter (ENA).