About SSM Agent - AWS Systems Manager

About SSM Agent

AWS Systems Manager Agent (SSM Agent) is Amazon software that can be installed and configured on an EC2 instance, an on-premises server, or a virtual machine (VM). SSM Agent makes it possible for Systems Manager to update, manage, and configure these resources. The agent processes requests from the Systems Manager service in the AWS Cloud, and then runs them as specified in the request. SSM Agent then sends status and execution information back to the Systems Manager service by using the Amazon Message Delivery Service (service prefix: ec2messages).

SSM Agent must be installed on each instance you want to use with Systems Manager. SSM Agent is preinstalled, by default, on instances created from the following Amazon Machine Images (AMIs):

  • Amazon Linux

  • Amazon Linux 2

  • Amazon Linux 2 ECS-Optimized AMIs

  • Ubuntu Server 16.04, 18.04, and 20.04

  • Windows Server 2008-2012 R2 AMIs published in November 2016 or later

  • Ubuntu Server 16.04, 18.04, 20.04, and 20.10

  • Windows Server 2016 and 2019


SSM Agent is not installed on all AMIs based on Amazon Linux or Amazon Linux 2. For example, SSM Agent is not preinstalled on EKS-Optimized AMIs based on Amazon Linux 2.

On other AMIs, and on on-premises servers and virtual machines for your hybrid environment, you must install the agent manually, as described in the table below.


An updated version of SSM Agent is released whenever new capabilities are added to Systems Manager or updates are made to existing capabilities. If an older version of the agent is running on an instance, some SSM Agent processes can fail. For that reason, we recommend that you automate the process of keeping SSM Agent up-to-date on your instances. For information, see Automating updates to SSM Agent. To be notified about SSM Agent updates, subscribe to the SSM Agent Release Notes page on GitHub.

Operating system type SSM Agent installation

Windows AMIs published before November 2016 use the EC2Config service to process requests and configure instances.

Unless you have a specific reason for using the EC2Config service or an earlier version of SSM Agent to process Systems Manager requests, we recommend that you download and install the latest version of the SSM Agent to each of your EC2 instances and managed instances in your hybrid environment. For more information, see Installing and configuring SSM Agent on EC2 instances for Windows Server.

Linux SSM Agent is installed by default on Amazon Linux, Amazon Linux 2, Ubuntu Server 16.04, and Ubuntu Server 18.04 LTS base EC2 AMIs. You must manually install SSM Agent on other versions of Amazon EC2 for Linux, including non-base images. For more information, see Installing and configuring SSM Agent on EC2 instances for Linux.
On-premises servers and VMs

SSM Agent must be installed manually on on-premises servers and virtual machines (VMs) you want to use in a hybrid environment. The SSM Agent download and installation process for these machines is different than the process used for EC2 instances. For more information, see the following topics: