# Update instance software on your AL2 instance It is important to keep software up to date. Packages in a Linux distribution are updated frequently to fix bugs, add features, and protect against security exploits. When you first launch and connect to an Amazon Linux instance, you might see a message asking you to update software packages for security purposes. This section shows how to update an entire system, or just a single package. This information applies to AL2. For information about AL2023, see [Manage packages and operating system updates in AL2023](https://docs.aws.amazon.com/linux/al2023/ug/managing-repos-os-updates.html) in the *Amazon Linux 2023 User Guide*. For information about changes and updates to AL2, see [AL2 release notes](https://docs.aws.amazon.com/AL2/latest/relnotes/relnotes-al2.html). For information about changes and updates to AL2023, see [AL2023 release notes](https://docs.aws.amazon.com/linux/al2023/release-notes/relnotes.html). **Important** If you launched an EC2 instance that uses an Amazon Linux 2 AMI into an IPv6-only subnet, you must connect to the instance and run `sudo amazon-linux-https disable`. This lets your AL2 instance connect to the yum repository in S3 over IPv6 using the http patch service. **To update all packages on an AL2 instance** 1. (Optional) Start a **screen** session in your shell window. Sometimes you might experience a network interruption that can disconnect the SSH connection to your instance. If this happens during a long software update, it can leave the instance in a recoverable, although confused state. A **screen** session allows you to continue running the update even if your connection is interrupted, and you can reconnect to the session later without problems. 1. Execute the **screen** command to begin the session. ``` [ec2-user ~]$ screen ``` 1. If your session is disconnected, log back into your instance and list the available screens. ``` [ec2-user ~]$ screen -ls There is a screen on: 17793.pts-0.ip-12-34-56-78 (Detached) 1 Socket in /var/run/screen/S-ec2-user. ``` 1. Reconnect to the screen using the **screen -r** command and the process ID from the previous command. ``` [ec2-user ~]$ screen -r 17793 ``` 1. When you are finished using **screen**, use the **exit** command to close the session. ``` [ec2-user ~]$ exit [screen is terminating] ``` 1. Run the **yum update** command. Optionally, you can add the `--security` flag to apply only security updates. ``` [ec2-user ~]$ sudo yum update ``` 1. Review the packages listed, enter **y**, and press Enter to accept the updates. Updating all of the packages on a system can take several minutes. The **yum** output shows the status of the update while it is running. 1. (Optional) [Reboot your instance](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-reboot.html) to ensure that you are using the latest packages and libraries from your update; kernel updates are not loaded until a reboot occurs. Updates to any `glibc` libraries should also be followed by a reboot. For updates to packages that control services, it might be sufficient to restart the services to pick up the updates, but a system reboot ensures that all previous package and library updates are complete. **To update a single package on an AL2 instance** Use this procedure to update a single package (and its dependencies) and not the entire system. 1. Run the **yum update** command with the name of the package to update. ``` [ec2-user ~]$ sudo yum update openssl ``` 1. Review the package information listed, enter **y**, and press Enter to accept the update or updates. Sometimes there will be more than one package listed if there are package dependencies that must be resolved. The **yum** output shows the status of the update while it is running. 1. (Optional) [Reboot your instance](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-reboot.html) to ensure that you are using the latest packages and libraries from your update; kernel updates are not loaded until a reboot occurs. Updates to any `glibc` libraries should also be followed by a reboot. For updates to packages that control services, it might be sufficient to restart the services to pick up the updates, but a system reboot ensures that all previous package and library updates are complete.