Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

AL2 on Amazon EC2

Launch Amazon EC2 instance with AL2 AMI

You can launch an Amazon EC2 instance with the AL2 AMI. For more information, see Step 1: Launch an instance.

Find the latest AL2 AMI using Systems Manager

Amazon EC2 provides Amazon Systems Manager public parameters for public AMIs maintained by Amazon that you can use when launching instances. For example, the EC2-provided parameter /aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2 is available in all Regions and always points to the latest version of the AL2 AMI in a given Region.

To find the latest AL2023 AMI using Amazon Systems Manager, see Get started with AL2023.

The Amazon EC2 AMI public parameters are available from the following path:

/aws/service/ami-amazon-linux-latest

You can view a list of all Amazon Linux AMIs in the current Amazon Region by running the following Amazon CLI command.

aws ssm get-parameters-by-path --path /aws/service/ami-amazon-linux-latest --query "Parameters[].Name"

To launch an instance using a public parameter

The following example uses the EC2-provided public parameter to launch an m5.xlarge instance using the latest AL2 AMI.

To specify the parameter in the command, use the following syntax: resolve:ssm:public-parameter, where resolve:ssm is the standard prefix and public-parameter is the path and name of the public parameter.

In this example, the --count and --security-group parameters are not included. For --count, the default is 1. If you have a default VPC and a default security group, they are used.

aws ec2 run-instances 
    --image-id resolve:ssm:/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2 
    --instance-type m5.xlarge 
    --key-name MyKeyPair

For more information, see Using public parameters in the Amazon Systems Manager User Guide and Query for the latest Amazon Linux AMI IDs Using Amazon Systems Manager Parameter Store.

Connect to an Amazon EC2 instance

There are several ways to connect to your Amazon Linux instance, including SSH, Amazon Systems Manager Session Manager, and EC2 Instance Connect. For more information, see Connect to your Linux instance in the Amazon EC2 User Guide.

SSH users and sudo

Amazon Linux does not allow remote root secure shell (SSH) by default. Also, password authentication is disabled to prevent brute force attacks. To enable SSH logins to an Amazon Linux instance, you must provide your key pair to the instance at launch. You must also set the security group used to launch your instance to allow SSH access. By default, the only account that can log in remotely using SSH is ec2-user. This account also has sudo privileges. If you enable remote root login, be aware that it is less secure than relying on key pairs and a secondary user.

AL2 AMI boot mode

AL2 AMIs don't have a boot mode parameter set. Instances launched from AL2 AMIs follow the default boot mode value of the instance type. For more information, see Boot modes in the Amazon EC2 User Guide.

Package repository

This information applies to AL2 and AL1. For information about AL2023, see Managing packages and operating system updates in the AL2023 User Guide.

AL2 and AL1 are designed to be used with online package repositories hosted in each Amazon EC2 Amazon Region. The repositories are available in all Regions and are accessed using yum update tools. Hosting repositories in each Region enables us to deploy updates quickly and without any data transfer charges.

If you don't need to preserve data or customizations for your instances, you can launch new instances using the current AL2 AMI. If you do need to preserve data or customizations for your instances, you can maintain those instances through the Amazon Linux package repositories. These repositories contain all the updated packages. You can choose to apply these updates to your running instances. Earlier versions of the AMI and update packages continue to be available for use, even as new versions are released.

To install packages, use the following command:

[ec2-user ~]$ sudo yum install package

If you find that Amazon Linux doesn't contain an application that you need, you can install the application directly on your Amazon Linux instance. Amazon Linux uses RPMs and yum for package management, and that is likely the most direct way to install new applications. You should check to see if an application is available in our central Amazon Linux repository first, because many applications are available there. From there, you can add these applications to your Amazon Linux instance.

To upload your applications onto a running Amazon Linux instance, use scp or sftp and then configure the application by logging in to your instance. Your applications can also be uploaded during the instance launch by using the PACKAGE_SETUP action from the built-in cloud-init package. For more information, see Using cloud-init on AL2.

Security updates

Security updates are provided using the package repositories. Both security updates and updated AMI security alerts are published in the Amazon Linux Security Center. For more information about Amazon security policies or to report a security problem, see Amazon Cloud Security.

AL1 and AL2 are configured to download and install critical or important security updates at launch time. Kernel updates are not included in this configuration.

In AL2023, this configuration has changed compared to AL1 and AL2. For more information about security updates for AL2023, see Security updates and features in the AL2023 User Guide.

We recommend that you make the necessary updates for your use case after launch. For example, you might want to apply all updates (not just security updates) at launch, or evaluate each update and apply only the ones applicable to your system. This is controlled using the following cloud-init setting: repo_upgrade. The following snippet of cloud-init configuration shows how you can change the settings in the user data text you pass to your instance initialization:

#cloud-config
repo_upgrade: security
     

The possible values for repo_upgrade are as follows:

The default setting for repo_upgrade is security. That is, if you don't specify a different value in your user data, by default, Amazon Linux performs the security upgrades at launch for any packages installed at that time. Amazon Linux also notifies you of any updates to the installed packages by listing the number of available updates upon login using the /etc/motd file. To install these updates, you need to run sudo yum upgrade on the instance.

Repository configuration

For AL1 and AL2, AMIs are a snapshot of the packages available at the time the AMI was created, with the exception of security updates. Any packages not on the original AMI, but installed at runtime, will be the latest version available. To get the latest packages available for AL2, run yum update -y.

For AL2023, the repository configuration has changed compared to AL1 and AL2. For more information about the AL2023 repository, see Managing packages and operating system updates.

Versions up to AL2023 were configured to deliver a continuous flow of updates to roll from one minor version of Amazon Linux to the next version, also called rolling releases. As a best practice, we recommend you update your AMI to the latest available AMI rather than launching old AMIs and applying updates.

In-place upgrades are not supported between major Amazon Linux versions, such as from AL1 to AL2 or from AL2 to AL2023. For more information, see Amazon Linux availability.