When did AWS Systems Manager launch?

AWS Systems Manager was announced on November 29, 2017, unifying and extending the capabilities of Amazon EC2 Systems Manager, which had been announced at AWS re:Invent on December 1, 2016. Its roots go back further, to the Amazon Simple Systems Manager (SSM) API (API version 2014-11-06) and the AWS System Manager for Microsoft SCVMM add-in announced on October 29, 2014.

Why is AWS Systems Manager abbreviated as SSM?

The abbreviation SSM comes from the predecessor API and agent named Amazon Simple Systems Manager (SSM). The legacy naming survives in the service endpoint (ssm.[region].amazonaws.com), the AWS CLI (aws ssm), the SDK class names, IAM policies and ARNs, and AWS CloudFormation resource types (AWS::SSM::*).

When did Session Manager launch, and how has remote access evolved?

AWS Systems Manager Session Manager launched on September 11, 2018, providing interactive remote connections without opening inbound ports or managing SSH keys. Port forwarding to remote hosts was added on May 27, 2022, and just-in-time node access, which enables zero-standing-privilege, time-bound access approval, launched on April 29, 2025.

What is Default Host Management Configuration (DHMC) and when did it launch?

Default Host Management Configuration (DHMC), launched on February 17, 2023, enables AWS Systems Manager by default for all Amazon EC2 instances in an account by granting the required permissions at the account level, without modifying individual instance profile roles. On October 13, 2023, it was extended so that it can be enabled across an entire AWS Organization.

Which AWS Systems Manager capabilities have been closed to new customers?

As announced on October 13, 2025, Systems Manager Change Manager and Incident Manager no longer accept new customers as of November 7, 2025, and have moved to maintenance mode, with OpsCenter positioned as an alternative for incident response. As announced on June 30, 2026, Application Manager no longer accepts new customers as of July 30, 2026. Existing customers can continue to use these capabilities.

When did Parameter Store add cross-account sharing?

AWS Systems Manager Parameter Store added cross-account sharing on February 22, 2024. Advanced-tier parameters can be shared with other AWS accounts through AWS Resource Access Manager, so multiple accounts can reference a single source of truth for configuration data.

AWS History and Timeline regarding AWS Systems Manager - Overview, Functions, Features, Summary of Updates, and Introduction to SSM

First Published: 2023-06-11
Last Updated: 2026-07-04

In the previous article, "AWS History and Timeline regarding Amazon S3 - Focusing on the evolution of features, roles, and prices beyond mere storage", I introduced the history of Amazon S3 and changes in its prices.
This time, I created a historical timeline of AWS Systems Manager(SSM) which has had name changes and various functions have been integrated over the years.
However, unlike last time, this time I am focusing only on the main features of SSM, omitting changes in prices and minor updates.
Also, I have summarized the "Current Overview, Functions, Features of AWS Systems Manager" as of the time of writing this article.

Background and Method of Creating AWS Systems Manager Historical Timeline

The reason for creating the history timeline of AWS Systems Manager (SSM) this time is because various functions that form the basis of SSM have been announced, integrated, and renamed over the years, and the current functions of SSM are also very extensive. Therefore, I wanted to summarize the information of SSM with the following approach.

Organize the transition of features included in SSM while following the history of the appearance and integration of services that form the basis of SSM
Summarizing the feature list and characteristics of SSM

This timeline primarily references the following blogs and document history regarding AWS Systems Manager.

There may be slight variations in the dates on the timeline due to differences in the timing of announcements or article postings in the references used.
The content posted is limited to major features related to the current AWS Systems Manager and necessary for the feature list and overview description.
In other words, please note that the items on this timeline are not all updates to AWS Systems Manager features, but are representative updates that I have picked out.

AWS Systems Manager Historical Timeline (Updates from October 29, 2014)

Now, this is the timeline about the features of AWS Systems Manager.
The history of AWS Systems Manager spans nearly twelve years from October 2014, but the integration of features and the associated name changes are complex, and new features have been announced almost every year since it became the current AWS Systems Manager.

2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026

* You can sort the table by clicking on the column name.

Date	Summary
2014-10-29	An interface implemented as a VMM console add-on to manage AWS resources such as Amazon EC2 instances from Microsoft SCVMM, AWS System Manager for Microsoft System Center Virtual Machine Manager (SCVMM) is announced. References: New Microsoft System Center Virtual Machine Manager Add-In
2014-11-06	Amazon Simple Systems Manager(SSM) API Version becomes 2014-11-06. References: Tech Blog with curated related content AWS SDK for PHP 3.x - Amazon Simple Systems Manager(SSM)2014-11-06 Class: AWS.SSM — AWS SDK for JavaScript AWS Systems Manager API Reference API Version 2014-11-06
2015-01-21	AWS Systems Manager for Microsoft System Center Virtual Machine Manager(SCVMM) is updated. It now allows importing of existing virtual machines and launching new Amazon EC2 instances without using the AWS Management Console. References: System Center Virtual Machine Manager Add-In Update – Import & Launch Instances
2015-02-17	A method is introduced for Windows Amazon EC2 instances to join a domain at startup using the EC2Config and EC2 SSM (Simple Systems Manager) API, which allows PowerShell script execution on Windows instances, installation, repair, and uninstallation of MSI packages. References: Seamlessly Join EC2 Instances to a Domain
2015-10-26	EC2 Run Command is announced, which allows the installation of software, execution of scripts and Microsoft PowerShell commands, and configuration of Windows Update settings on Windows instances using the AWS Management Console, AWS CLI, AWS SDK, and AWS Tools for Windows PowerShell. References: New EC2 Run Command – Remote Instance Management at Scale
2016-05-12	EC2 Run Command is updated, and the Simple Systems Manager(SSM) agent for Linux becomes available. References: EC2 Run Command Update – Manage & Share Commands and More
2016-12-01	Amazon EC2 Systems Manager is announced as a series of services to manage Windows or Linux hosts running on Amazon EC2 instances, adding and integrating the following features, including EC2 Run Command. Run Command, State Manager, Parameter Store, Maintenance Window, Software Inventory, Patch Management, Automation, Integration with AWS Config References: Tech Blog with curated related content EC2 Systems Manager – Configure & Manage EC2 and On-Premises Systems * Amazon Simple Systems Manager(SSM) is positioned as an agent installed on instances to execute management by EC2 Systems Manager. References: How to Simplify Security Assessment Setup Using Amazon EC2 Systems Manager and Amazon Inspector
2017-11-29	AWS Systems Manager, which provides tools extended to Amazon EC2 and other AWS services, is announced, incorporating the features of Amazon EC2 Systems Manager and adding the following new features. Resource Groups, Insights (Compliance Dashboard, integration of existing CloudWatch Dashboard and Personal Health Dashboard (PHD) within the SSM console) References: AWS Systems Manager – A Unified Interface for Managing Your Cloud and Hybrid Resources
2018-09-11	The AWS Systems Manager Session Manager feature is added. References: Introducing AWS Systems Manager Session Manager
2019-06-07	AWS Systems Manager OpsCenter feature is added. References: Introducing AWS Systems Manager OpsCenter to enable faster issue resolution
2019-11-19	AWS Systems Manager Explorer feature is added. References: Introducing AWS Systems Manager Explorer
2019-11-25	AWS AppConfig is added as one of the features of AWS Systems Manager. References: Simplify application configuration with AWS AppConfig
2020-01-06	AWS Systems Manager Change Calendar feature is added. References: Introducing AWS Systems Manager Change Calendar
2020-12-15	AWS Systems Manager Application Manager feature is added. References: Introducing AWS Systems Manager Application Manager
2020-12-15	AWS Systems Manager Change Manager feature is added. References: Introducing AWS Systems Manager Change Manager
2020-12-15	AWS Systems Manager Fleet Manager feature is added. References: Introducing AWS Systems Manager Fleet Manager
2021-05-10	AWS Systems Manager Incident Manager feature is added. References: Introducing Incident Manager from AWS Systems Manager
2022-05-27	AWS Systems Manager Session Manager now supports port forwarding to remote hosts. References: AWS Systems Manager announces support for port forwarding to remote hosts using Session Manager
2022-09-30	AWS Systems Manager can now control tasks using Amazon CloudWatch metrics. References: AWS Systems Manager adds CloudWatch Alarms to control tasks
2023-01-17	AWS Systems Manager Patch Policies are introduced in Quick Setup, enabling centralized patching across accounts and Regions in AWS Organizations. Patch policies let administrators define and enforce patch compliance from a single console experience spanning multiple accounts and Regions, powered by Patch Manager, without configuring patch groups, maintenance windows, and State Manager associations per account and Region. References: AWS Systems Manager announces Patch Policies, enabling cross account and cross Region patching
2023-02-17	Default Host Management Configuration (DHMC) is introduced, enabling AWS Systems Manager by default across all Amazon EC2 instances in an account. DHMC grants EC2 instances the permissions to connect to Systems Manager at the account level in a single action, without modifying individual instance profile roles, so that core capabilities such as Patch Manager, Session Manager, and Inventory become available automatically. References: Announcing the ability to enable AWS Systems Manager by default across all EC2 instances in an account
2023-02-23	AWS Systems Manager for SAP becomes generally available. It captures SAP landscape topology metadata so that AWS tooling understands SAP-specific application server and database interdependencies, with initial support for backing up SAP HANA databases using AWS Backup and the AWS Backint Agent. References: AWS Systems Manager for SAP is now generally available, with initial support for backing up SAP HANA databases using AWS Backup
2023-10-13	Default Host Management Configuration (DHMC) is extended to cover all Amazon EC2 instances across an entire AWS Organization. A delegated administrator can enable Systems Manager management permissions organization-wide with a single action, building on the account-level DHMC launch of February 2023. References: Announcing ability to enable AWS Systems Manager by default for all EC2 instances in an organization
2023-11-26	AWS Systems Manager Automation adds a low-code visual design experience for authoring runbooks (preview). Automation actions and AWS APIs can be dragged and dropped onto a canvas to visualize runbook logic, with real-time parameter validation, error highlighting, and best-practice recommendations. References: AWS Systems Manager Automation makes it easier to author runbooks with new low-code visual design experience
2024-02-22	AWS Systems Manager Parameter Store supports cross-account sharing of advanced-tier parameters. Parameters can be shared with other AWS accounts via AWS Resource Access Manager, maintaining a single source of truth for configuration data instead of duplicating it across accounts. References: AWS Systems Manager Parameter Store now supports cross-account sharing
2024-11-21	A new AWS Systems Manager experience is announced, built around a unified, cross-account and cross-Region node management console. The redesigned experience provides a centralized dashboard for all managed and unmanaged nodes across an organization's accounts and Regions, spanning Amazon EC2 instances, hybrid servers, and multicloud environments, with detection and remediation of unmanaged nodes and integration with Amazon Q Developer for natural-language queries about node fleets. References: The new AWS Systems Manager experience: Simplifying node management
2025-04-29	Just-in-time node access is launched, enabling zero-standing-privilege connections to managed nodes. Operators request time-bound access to nodes across AWS, hybrid, and multicloud environments before connecting via Session Manager, governed by policy-based auto-approval, manual approval, or deny rules, and the feature can be enabled per account, per organizational unit, or organization-wide. References: AWS Systems Manager launches just-in-time node access
2025-05-07	Customization options are added for onboarding to the unified node management experience. Customers can enable or disable the default EC2 instance permissions granted via DHMC, set the inventory metadata collection frequency, and define the SSM Agent auto-update cadence during onboarding. References: AWS Systems Manager adds customization options for onboarding configuration
2025-08-14	AWS Systems Manager Automation enhances runbook execution control. New capabilities include re-executing runbooks from the console with pre-populated parameters, automatic retry of throttled API calls during high-concurrency runs, and nested organizational-unit targeting. References: AWS Systems Manager Automation enhances runbook execution control and updates free tier
2025-10-13	AWS announces that Systems Manager Change Manager and Incident Manager will no longer accept new customers starting November 7, 2025. Both capabilities move to maintenance mode as part of an AWS service availability update; existing customers can continue using them, and AWS points to Systems Manager OpsCenter as an alternative path for incident response. References: AWS Service Availability Updates (October 2025)
2025-12-01	AWS Systems Manager for SAP adds automated best-practice compliance validation for SAP ABAP applications. The checks test SAP ABAP applications against the AWS Well-Architected Framework SAP Lens, complementing existing SAP HANA checks, and can run on a schedule or on demand with Amazon EventBridge integration. References: Validate best practice compliance for SAP ABAP applications with AWS Systems Manager
2026-06-30	AWS announces that Systems Manager Application Manager will no longer accept new customers starting July 30, 2026. Application Manager moves to maintenance mode as part of an AWS service availability update; existing customers retain access, and other Systems Manager capabilities are not affected. References: AWS Service Availability Updates (June 2026)

About the Abbreviation "SSM" for AWS Systems Manager

From the timeline above, the abbreviation "SSM", which is still used as a short name for AWS Systems Manager, comes from the predecessor API, agent - Amazon Simple Systems Manager(SSM).

Examples of AWS Resources with Remnants of SSM

Service Endpoint (ssm.[region name].amazonaws.com)
AWS CLI (aws ssm [command])
AWS SDK (Class: AWS.SSM)
IAM (policy name, action name, ARN, etc.)
AWS CloudFormation (AWS::SSM::[resource name], etc.)
AWS Config (AWS::SSM::[resource name], etc.)
AWS Systems Manager Features (SSM Agent, SSM Parameters, etc.)

About the Relationship of the Services Appearing in the Timeline

Relationship with the Current AWS Systems Manager

The services that are the origin of the current AWS Systems Manager and were later integrated are, in the order they appear in the timeline, Amazon Simple Systems Manager(SSM) API, EC2 Run Command, Simple Systems Manager(SSM) Agent, and Amazon EC2 Systems Manager.
On the other hand, AWS Systems Manager for Microsoft System Center Virtual Machine Manager(SCVMM), which first appeared with the name "AWS System Manager", is still introduced as a tool for Amazon EC2.

Relationship between EC2Config and SSM Agent

EC2Config, which appears in the timeline, is a tool installed on Amazon EC2 instances before Windows Server 2016 to automate initial setup tasks.
It has now been replaced by EC2Launch for Windows Server 2016 and 2019, and EC2Launch v2 which widely supports from Windows Server 2008 SP2 to Windows Server 2022.
In 2015, remote execution of OS commands was done using EC2Config on Windows Amazon EC2 instances (in the latest versions of EC2Config, EC2Launch, and EC2Launch v2, the SSM agent is installed as part of the functionality, and the OS command execution function has also been transitioned to Run Command).
However, EC2Config did not support Linux Amazon EC2 instances, so the Simple Systems Manager(SSM) agent appeared as an agent for remote execution of OS commands on Linux Amazon EC2 instances.

Current Overview, Functions, Features of AWS Systems Manager

Here I introduce the current overview, functions, features of AWS Systems Manager.
AWS Systems Manager is divided into four core feature groups (Operation Management, Application Management, Change Management, Node Management), and multiple features are categorized in each.
In addition, on 2024-11-21 AWS announced a new AWS Systems Manager experience built around a unified, cross-account and cross-Region node management console, which provides a centralized dashboard for all managed and unmanaged nodes across an organization, spanning Amazon EC2 instances, hybrid servers, and multicloud environments.

AWS Systems Manager Use Cases

AWS Systems Manager is typically used in the following scenarios:

Secure remote access without SSH/RDP exposure: Connecting to Amazon EC2 instances and hybrid servers via Session Manager without opening inbound ports, managing SSH keys, or maintaining bastion hosts, optionally with just-in-time, time-bound access approval.
Patch and configuration compliance: Automating OS and application patching with Patch Manager and patch policies, and keeping server configurations consistent with State Manager, with results aggregated in Compliance.
Operational automation: Encoding operational procedures as Automation runbooks and Run Command documents for repeatable, auditable maintenance tasks across large fleets.
Configuration and secrets referencing: Centralizing application settings in Parameter Store (including cross-account sharing of advanced-tier parameters) and feature flags in AppConfig.
Hybrid and multicloud node management: Managing on-premises servers and servers in other clouds alongside Amazon EC2 instances through Hybrid Activations, Fleet Manager, and the unified node management experience.
Operations visibility and issue tracking: Aggregating operational data with Explorer and managing operational issues (OpsItems) with OpsCenter.

AWS Systems Manager Key Functions and Features

The main functions and features of AWS Systems Manager are organized in the following four groups, and each capability is described in detail in the sections below.

Operations Management: Explorer, OpsCenter, CloudWatch Dashboard, AWS Health Dashboard (formerly Personal Health Dashboard), Incident Manager
Application Management: Application Manager, AppConfig, Parameter Store
Change Management: Change Manager, Automation, Change Calendar, Maintenance Windows
Node Management: Fleet Manager, Hybrid Activations, Default Host Management Configuration (DHMC), Session Manager, Just-in-time node access, Run Command, Patch Manager, State Manager, Compliance, Inventory, Distributor

Operations Management

Explorer

AWS Systems Manager Explorer provides a dashboard that aggregates OpsData (operation data) across your AWS account and AWS regions, helping you visualize and identify operational issues that need to be addressed. The data sources for OpsData include the following.

OpsItems (operational tasks) of AWS Systems Manager OpsCenter
AWS Systems Manager Patch Manager
Amazon EC2
AWS Trusted Advisor
AWS Compute Optimizer
Cases of AWS Support Center
AWS Config
AWS Security Hub

For example, you can use AWS Systems Manager Explorer to check high-priority issues in OpsItems of AWS Systems Manager OpsCenter and try to resolve the issues by running AWS Systems Manager Automation from AWS Systems Manager OpsCenter.

OpsCenter

AWS Systems Manager OpsCenter provides the functionality to aggregate, standardize, investigate, and correct operational issues in OpsItems (operational tasks) related to AWS resources, provide relevant data for problem resolution, and provide Runbooks of AWS Systems Manager Automation.
Since OpsCenter is integrated with the previously mentioned AWS Systems Manager Explorer, an environment where you can check OpsItems of OpsCenter and OpsData of Explorer containing OpsItems is created simultaneously.
By using OpsCenter, you can centrally check the following relevant data that is useful for investigation and correction.

Details of events, resources, accounts
Past OpsItems with similar characteristics
Changes and relationships of related AWS Config
AWS CloudTrail logs
Amazon CloudWatch alarms
AWS CloudFormation stacks
Other quick links to access logs and metrics
List of Runbooks and recommended Runbooks
Additional information passed to OpsCenter through AWS services

CloudWatch Dashboard

This is a shortcut to access the Amazon CloudWatch Dashboard, which is managed and displayed within the Amazon CloudWatch console, from the AWS Systems Manager console. It is useful when you need to use the Amazon CloudWatch Dashboard while using the features of AWS Systems Manager.

Personal Health Dashboard (PHD)

This is a shortcut to access the Personal Health Dashboard from the AWS Systems Manager console. It is useful when you need to use the Personal Health Dashboard while using the features of AWS Systems Manager.
Note that the AWS Personal Health Dashboard has since been renamed the AWS Health Dashboard.

Incident Manager

AWS Systems Manager Incident Manager is an incident management console designed to mitigate and recover incidents that affect applications.
Note: As announced on 2025-10-13, Incident Manager no longer accepts new customers as of November 7, 2025, and has moved to maintenance mode; existing customers can continue to use it, and AWS Systems Manager OpsCenter is positioned as an alternative path for incident response.
Incident Manager provides the following features to be used in each phase of the incident plan and the incident lifecycle.

[Flow of incident lifecycle]

Incident plan: 0
Incident lifecycle: 1 → 2 → 3 → 4 → Back to 1

0. Incident Plan

In the incident plan, we use the following features of the Incident Manager to create a response plan.

Contact
Set up the contact information and contact channels (Email, SMS, voice) of the responders to be contacted when an incident occurs.
Escalation Plan
Set the order of the contacts to be called next if a contact does not receive an incident.
Runbook
Define what can be automated among the response procedures to investigate and mitigate the impact when an incident occurs as the Runbook (Automation Document) of AWS Systems Manager Automation.
AWS Chatbot
Choose and set up Amazon Chime or Slack used by the responder for continuous incident updates from AWS Chatbot.
Response Plan
Create a response plan in case of an incident using the aforementioned contact, escalation plan, runbook, AWS Chatbot.
Creation of an Incident
Create an incident based on the response plan created above from either Amazon CloudWatch, Amazon EventBridge, or Incident Manager and set it so that the response plan is executed when an incident occurs.

1. Alerts and Engagement

We monitor incidents with Amazon CloudWatch, Amazon EventBridge, and execute the response plan when an incident occurs.
Based on the response plan, escalation to the responder and update notification of incident information by AWS Chatbot are carried out.

2. Triage

The responder assigns priorities to incidents in the following impact assessment.
　　1. Significant impact
　　2. Large impact
　　3. Moderate impact
　　4. Minor impact
　　5. No impact

3. Investigation and Mitigation

Useful information for investigating incidents is provided in the metrics and timeline of the Incident Manager's incident detail page, and the execution of investigation procedures and impact mitigation response procedures predefined in the Runbook of AWS Systems Manager Automation are carried out.

4. Post-Incident Analysis

After completing the incident response, we record the situation of the incident and response by answering questions in the incident analysis feature of Incident Manager.
The questions used in incident analysis are defined in the AWS standard or a predefined analysis template.
Answer questions related to incident overview, impact, metrics, timeline, actions (improvements), etc. defined in this analysis template, and use the analysis to promote improvement.
Important points in the description of incident analysis questions are to take advantage of the benefits of incident impact analysis, understanding the root cause of the problem, dealing with the root cause through improvements, improving incident response, and sharing information learned from incidents within the organization. The purpose is to not to mention people's names, not to blame.

Application Management

Application Manager

AWS Systems Manager Application Manager is a feature that allows centralized management of multiple AWS applications from a single console, such as monitoring and executing actions.
Note: As announced on 2026-06-30, Application Manager no longer accepts new customers as of July 30, 2026, and has moved to maintenance mode; existing customers can continue to use it.
The categories that can be added to the Application Manager dashboard are applications (custom applications, Launch Wizard, CloudFormation stack, AppRegistry applications) and container clusters (Amazon ECS clusters, Amazon EKS clusters).
The information that can be displayed on the Application Manager dashboard includes the following:

Overview of applications
Details of each resource
Compliance information by AWS Systems Manager State Manager
Monitoring by Amazon CloudWatch Application Insights
OpsItems by AWS Systems Manager OpsCenter
Logs of Amazon CloudWatch Logs
Runbook of AWS Systems Manager Automation

In addition to the above, each category that can be added to the dashboard has its own unique information display and operation, and you can also execute AWS Systems Manager Automation Runbook.

AppConfig

AWS AppConfig is a service that manages, validates, and safely deploys and monitors configuration data and settings used in applications hosted on Amazon EC2 instances, AWS Lambda, containers, mobile applications, IoT devices, etc.
The configuration data and settings used by AWS AppConfig can be obtained from the configuration store hosted by AWS AppConfig, Amazon S3, AWS Systems Manager Parameter Store, AWS Systems Manager Document Store.
You can also retrieve them from AWS CodeCommit, GitHub, Bitbucket Pipelines using AWS CodePipeline.

Parameter Store

AWS Systems Manager Parameter Store provides secure hierarchical storage to manage settings data and sensitive information such as passwords, database strings, AMI ID, license codes, etc., as parameters.
Parameter values can be stored as plain text or encrypted data, and are referenced by unique parameter names in scripts, commands, SSM documents, configurations, automation workflows, etc.
Since 2024-02-22, advanced-tier parameters can also be shared across AWS accounts via AWS Resource Access Manager, so that multiple accounts can reference a single source of truth for configuration data.
The AWS Systems Manager Parameter Store is very similar in features to the AWS Secrets Manager, but has the following main differences:

It does not have integration features with database services including Aurora, RDS, Redshift, DocumentDB
It does not have automatic rotation functionality for authentication information with database services and others
Standard parameters of standard throughput can be used for free

On the other hand, an API is provided to reference AWS Secrets Manager secrets from the AWS Systems Manager Parameter Store.
Therefore, without implementing secret acquisition in the AWS Secrets Manager library, you can obtain AWS Secrets Manager secrets from the AWS Systems Manager Parameter Store.

Change Management

Change Manager

AWS Systems Manager Change Manager is a change management framework for requesting, approving, implementing, and reporting application configuration and operational changes.
It also supports integration with AWS services such as Amazon CloudWatch alarms, AWS Systems Change Calendar, AWS Organizations, and AWS IAM Identity Center (successor to AWS Single Sign-On).
Note: As announced on 2025-10-13, Change Manager no longer accepts new customers as of November 7, 2025, and has moved to maintenance mode; existing customers can continue to use it.

Automation

AWS Systems Manager Automation is a feature that automates common and repetitive IT operations and management tasks.
AWS Systems Manager Automation executes a procedure book in JSON or YAML format, called a Runbook (formerly: Automation document), which defines actions for AWS resources in one or more steps.
In the Runbook, you can define actions such as script execution, AWS API execution, AWS Lambda function execution, AWS StepFunctions execution, AWS Systems Manager runCommand execution, AWS Systems Manager Automation execution, AWS CloudFormation stack creation, Amazon EC2 instance startup, AMI creation, conditional branching (step jump) execution, manual approval, etc.

Change Calendar

AWS Systems Manager Change Calendar is a feature that provides schedule information for determining the feasibility of actions by setting a schedule in a date and time range and referring to it from AWS Systems Manager Automation Runbook, etc.
The types of calendars that can be created are as follows:

Open by default
A type that creates events where actions are not executed for calendars where actions are executed by default
Closed by default
A type that creates events where actions are executed for calendars where actions are not executed by default

In addition, it supports the import of iCalendar files (.ics) from Google Calendar, Microsoft Outlook, and iCloud Calendar, so you can bulk import events such as holidays.

Maintenance Windows

AWS Systems Manager Maintenance Windows is a feature that schedules time frames for executing tasks such as installing patches and updates for management and maintenance across multiple instances.
By automatically executing tasks in the time frame specified by Maintenance Windows, you can minimize the impact of operational and infrastructure failures.
The schedule for maintenance windows is set using Cron/Rate format or Cron/Rate schedule builder created from the console.
The tasks for the maintenance window can be selected from AWS Systems Manager Run Command, AWS Systems Manager Automation, AWS Step Functions, and AWS Lambda, and the target instances for the tasks can be selected by tagging, resource groups, or manual selection.

Node Management

Fleet Manager

AWS Systems Manager Fleet Manager is a function for fleet management, such as performance, file system, process, user and group information management within the OS, and access management using IAM roles and policies, on managed instances where the SSM agent has been installed, such as on-premises and EC2 instances.
Servers handled in on-premises or clouds other than AWS can be managed as managed instances in Fleet Manager by registering them with the Hybrid Activations described later.
Furthermore, by enabling the advanced instance layer on the managed instances of servers handled in on-premises or clouds other than AWS that have been registered in Fleet Manager, you can have remote access via the browser or AWS CLI in the Session Manager described later.

Hybrid Activations

AWS Systems Manager Hybrid Activations is a function to manage servers handled in on-premises or clouds other than AWS as managed instances in Fleet Manager.
You can register a server as a managed instance in Fleet Manager by creating a hybrid activation in the Systems Manager console or AWS CLI, and then running the registration command using the activation code and activation ID on the activation target server where the SSM agent has been installed.

Default Host Management Configuration (DHMC)

Default Host Management Configuration (DHMC), introduced on 2023-02-17, is a setting that enables AWS Systems Manager by default for all Amazon EC2 instances in an account.
DHMC grants EC2 instances the permissions required to connect to Systems Manager at the account level in a single action, without modifying individual instance profile roles, so that core capabilities such as Patch Manager, Session Manager, and Inventory become available automatically for new and existing instances.
Since 2023-10-13, DHMC can also be enabled for all EC2 instances across an entire AWS Organization by a delegated administrator.
Default Host Management Configuration - AWS Systems Manager

Session Manager

AWS Systems Manager Session Manager is a function to execute interactive remote connections via a browser-based or AWS CLI.
Preparation of a jump host, management of SSH keys, and opening of inbound ports are not necessary, and it is possible to audit session activities with AWS CloudTrail, and to record session data logs with Amazon CloudWatch Logs or Amazon S3, which helps improve access management and auditability of servers.
In the case of remote access to servers handled in on-premises or clouds other than AWS via Session Manager, it is necessary to register with Hybrid Activations and manage as a managed instance in Fleet Manager, and to enable an advanced instance layer.

Just-in-time Node Access

Just-in-time node access, launched on 2025-04-29, enables zero-standing-privilege connections to managed nodes.
Instead of granting operators standing access, administrators can require operators to request time-bound access to nodes across AWS, hybrid, and multicloud environments before connecting via Session Manager, governed by policy-based auto-approval, manual approval, or deny rules, and the feature can be enabled per account, per organizational unit, or organization-wide.
Just-in-time node access - AWS Systems Manager

Run Command

AWS Systems Manager Run Command is a function to automate remote execution of general management tasks such as registry editing, user management, and software and patch installation on Amazon EC2 instances or servers handled in on-premises or clouds other than AWS.
Preparation of a jump host, management of SSH keys, and opening of inbound ports are not necessary, and it is possible to audit session activities with AWS CloudTrail, and to record session data logs with Amazon CloudWatch Logs or Amazon S3, which helps improve access management and auditability of servers.
The difference between Session Manager and Run Command is that while Session Manager provides free command line operations of login users through interactive remote connections similar to SSH connections, Run Command only performs predefined command executions.

Patch Manager

AWS Systems Manager Patch Manager is a feature that automates the process of patch application for operating systems and applications on Amazon EC2 instances or servers managed on-premises or in non-AWS clouds.
Patch application rules for Patch Manager are specified by a patch baseline, and it's possible to set up rules such as approval/denial lists for patch application, rules to automatically approve within a few days from the release of the patch, and more.
The target for patch application is specified by adding servers managed on-premises or in non-AWS clouds as Amazon EC2 instances or as managed instances in Fleet Manager to a patch group with tags or instance IDs.
Patch application based on this patch baseline is executed by AWS Systems Manager Run Command.
On the other hand, AWS Systems Manager Maintenance Windows, which was mentioned earlier, can specify Run Command as a task, so you can also execute patch application from Patch Manager by specifying a Run Command task from Maintenance Windows and targeting the tags that have been specified for the patch group at a preset time frame.

State Manager

AWS Systems Manager State Manager is a feature that manages configuration by defining server configuration, virus protection definitions, firewall settings, applications, etc. on Amazon EC2 instances or servers managed on-premises or in non-AWS clouds as a state to consistently maintain.
Targets for state application can be selected from methods like tagging, resource groups, individual selection, or targeting all managed instances.
For servers managed on-premises or in non-AWS clouds, it is necessary to register with Hybrid Activations and manage them as managed instances in Fleet Manager.
The state to be applied to the target is defined in an SSM document that describes configuration management tasks such as application installation, Amazon CloudWatch configuration, execution of AWS Systems Manager Automation, execution of PowerShell and shell scripts.
By creating associations of these targets, SSM documents, and schedules (Cron/Rate format), you can automatically execute configuration management tasks.

Compliance

AWS Systems Manager Compliance is a feature that collects patch application status from AWS Systems Manager Patch Manager and configuration information from associations in AWS Systems Manager State Manager, and reports compliance or discrepancies with standard compliance or custom compliance.

Inventory

AWS Systems Manager Inventory is a feature that collects metadata related to instances and software, such as applications, files, network settings, services, registries, server roles, updates, and other system properties, from servers managed on-premises or in non-AWS clouds as Amazon EC2 instances or as managed instances in Fleet Manager.
You can manage applications, licenses, file lists, etc. using the collected data.

Distributor

AWS Systems Manager Distributor is a feature that, in conjunction with other AWS Systems Manager features such as Run Command and State Manager, manages the lifecycle of packages such as version management of software to be used on servers managed on-premises or in non-AWS clouds as Amazon EC2 instances or as managed instances in Fleet Manager, scheduled deployment, and more.

References:
Tech Blog with curated related content
Microsoft Products on AWS (including AWS add-ins for Microsoft System Center)
Configure a Windows instance using the EC2Config service
Configure a Windows instance using EC2Launch
Configure a Windows instance using EC2Launch v2
AWS Documentation - AWS Systems Manager
AWS Systems Manager
What's New with AWS?
AWS News Blog

Frequently Asked Questions about AWS Systems Manager History

When did AWS Systems Manager launch?: AWS Systems Manager was announced on November 29, 2017, unifying and extending the capabilities of Amazon EC2 Systems Manager, which had been announced at AWS re:Invent on December 1, 2016. Its roots go back further, to the Amazon Simple Systems Manager (SSM) API (API version 2014-11-06) and the AWS System Manager for Microsoft SCVMM add-in announced on October 29, 2014.
Why is AWS Systems Manager abbreviated as SSM?: The abbreviation SSM comes from the predecessor API and agent named Amazon Simple Systems Manager (SSM). The legacy naming survives in the service endpoint (ssm.[region].amazonaws.com), the AWS CLI (aws ssm), the SDK class names, IAM policies and ARNs, and AWS CloudFormation resource types (AWS::SSM::*).
When did Session Manager launch, and how has remote access evolved?: AWS Systems Manager Session Manager launched on September 11, 2018, providing interactive remote connections without opening inbound ports or managing SSH keys. Port forwarding to remote hosts was added on May 27, 2022, and just-in-time node access, which enables zero-standing-privilege, time-bound access approval, launched on April 29, 2025.
What is Default Host Management Configuration (DHMC) and when did it launch?: Default Host Management Configuration (DHMC), launched on February 17, 2023, enables AWS Systems Manager by default for all Amazon EC2 instances in an account by granting the required permissions at the account level, without modifying individual instance profile roles. On October 13, 2023, it was extended so that it can be enabled across an entire AWS Organization.
What is the new AWS Systems Manager experience announced in 2024?: On November 21, 2024, AWS announced a new AWS Systems Manager experience built around a unified, cross-account and cross-Region node management console. It provides a centralized dashboard for managed and unmanaged nodes across an organization's accounts and Regions, covering Amazon EC2 instances, hybrid servers, and multicloud environments, with integration with Amazon Q Developer for natural-language queries about node fleets.
Which AWS Systems Manager capabilities have been closed to new customers?: As announced on October 13, 2025, Systems Manager Change Manager and Incident Manager no longer accept new customers as of November 7, 2025, and have moved to maintenance mode, with OpsCenter positioned as an alternative for incident response. As announced on June 30, 2026, Application Manager no longer accepts new customers as of July 30, 2026. Existing customers can continue to use these capabilities.
When did Parameter Store add cross-account sharing?: AWS Systems Manager Parameter Store added cross-account sharing on February 22, 2024. Advanced-tier parameters can be shared with other AWS accounts through AWS Resource Access Manager, so multiple accounts can reference a single source of truth for configuration data.

All dates above follow the primary AWS sources referenced in this article (AWS What's New, AWS News Blog, and the service document history). This article is reviewed regularly to incorporate new AWS Systems Manager launches.

Summary

This time, I looked at the history of AWS Systems Manager as a timeline, including the integration and renaming of features and services named "Systems Manager", as well as a list and overview of the current AWS Systems Manager features.

When we actually trace the history, we can see that even if the name is the same, such as AWS Systems Manager for Microsoft SCVMM, there are tools that seem to be independent from the current AWS Systems Manager, the origin of the name SSM, and when and what features are available in SSM.

While there have been various changes, the common concept that comes to mind for AWS services and features with the name "Systems Manager" is "centralized operation management, remote execution, and automation".
In recent years this concept has been strengthened with Default Host Management Configuration, the unified cross-account and cross-Region node management experience announced in November 2024, and just-in-time node access, while some capabilities such as Change Manager, Incident Manager, and Application Manager have moved to maintenance mode.
It is expected that AWS Systems Manager will continue to provide tools that realize "centralized operation management, remote execution, and automation" not only for Amazon EC2 but also for hybrid and multicloud environments.
I would like to continue to watch the trends of what kind of features and tools AWS Systems Manager will provide in the future.
By the way, there is also a timeline for the entire history of AWS services, including services other than AWS Systems Manager, so please take a look if you are interested.

AWS History and Timeline - Almost All AWS Services List, Announcements, General Availability(GA)

I have also written related historical timelines for the services that AWS Systems Manager works most closely with:

This timeline will be updated as AWS Systems Manager continues to evolve.

Written by Hidekazu Konishi