AWS Systems Manager (SSM) Automation | Overview.

An Overview of AWS Systems Manager (SSM) Automation.

Focus:

•        Tailored for DevOps / SRE / DevSecOps  (aligned with regulated AWS environments).

Breakdown:

•        Intro,
•        The concept: SSM Automation,
•        Core Components,
•        Key Features,
•        Common Use Cases,
•        Enterprise Architecture View,
•        Automation Architecture,
•        Automation Runbooks (SSM Documents),
•        Sample Anatomy of an Automation Runbook,
•        Automation Actions (Key Capability),
•        State Management & Resilience,
•        IAM & Security Model,
•        Integration with Maintenance Windows,
•        Automation + Patch Manager (Enterprise Pattern)
•        Why This Matters,
•        Event-Driven Automation,
•        Logging, Audit & Compliance,
•        Enterprise Use Cases.

Intro:

•        Automation is a capability of AWS Systems Manager (SSM) to simplify, automate repetitive operational, management tasks across AWS resources and managed nodes. 

Core Components

•          The core component of Automation relies on runbooks (SSM documents), which are predeveloped packages of automated procedures and scripts that ensure consistent execution.
• SSM Automation is AWS’s state-driven, auditable, resumable workflow engine for operational change.

Automation is designed to:

•         Replace ad-hoc scripts
•         Enforce guardrails
•         Produce audit-grade evidence
•         Safely execute multi-step operational runbooks

Think of SSM Automation as:

“Infrastructure operations as code, with built-in control, rollback, and compliance.”

Key Features

Visual Designer:

•     A low-code interface for building runbooks via a drag-and-drop canvas.

Advanced Logic:

•     Support for complex workflows including loops, conditional branching, type transformations, and custom variables.

Multi-Account/Region:

•   Ability to execute automations across multiple AWS accounts and Regions from a central master account.

Common Use Cases,

Resource Management:

•   Creating AMIs, extending EBS volumes, and managing EC2 instance states.

Compliance and Patching:

•     Automatically applying security patches and remediating non-compliant resource configurations.

Cost Optimization:

•     Scheduling start/stop times for instances and deleting unused EBS snapshots.

2025 Pricing Update:

•         As of late 2025, AWS has begun phasing out the Automation free tier for existing users (ending December 31, 2025), while new users as of August 14, 2025, are no longer eligible for the free tier. 
• Charges are billed per automation step executed.

Enterprise Architecture View

Where Automation Fits in SSM

NB:

• Automation is the orchestration brain behind complex change.

Core Automation Architecture

Automation Runbooks (SSM Documents)

Document Types

•         Automation
•         Command
•         Policy

Automation runbooks are:

•         Versioned
•         Parameterized
•         Shareable (RAM)
•         Auditable

# Sample Anatomy of an Automation Runbook

# yaml

schemaVersion: '0.3'

description: Rolling patch with validation

assumeRole: "{{ AutomationAssumeRole }}"

parameters:

  InstanceId:

    type: String

  AutomationAssumeRole:

    type: String

mainSteps:

  - name: PreCheck

    action: aws:runCommand

    inputs:

      DocumentName: AWS-RunShellScript

      InstanceIds: ["{{ InstanceId }}"]

      Parameters:

        commands: ["systemctl status nginx"]

  - name: Patch

    action: aws:runCommand

    inputs:

      DocumentName: AWS-RunPatchBaseline

      InstanceIds: ["{{ InstanceId }}"]

  - name: Reboot

    action: aws:rebootInstance

Automation Actions (Key Capability)

NB:

• Automation uses typed actions, not raw scripts.

Common Actions

Action	Purpose
aws:runCommand	Execute commands
aws:executeAwsApi	Call any AWS API
aws:branch	Conditional logic
aws:approve	Human approval
aws:waitForAwsResourceProperty	Poll resource state
aws:rebootInstance	Controlled reboot
aws:changeInstanceState	Start/Stop
aws:invokeLambdaFunction	Custom logic

NB:

• This gives Automation native AWS awareness, unlike shell scripts.

State Management & Resilience

Automation executions are:

•         Stateful
•         Restartable
•         Step-aware

If execution fails:

•         Resume from last failed step
•         Rollback steps can be triggered
•         Full execution history retained

NB:

• This is why Automation is trusted in Prod.

IAM & Security Model

Automation Assume Role

• Automation runs as an IAM role, not a user.

Capabilities:

•         Scoped AWS API permissions
•         Environment-specific roles
•         Cross-account execution

Best practice:

AutomationRole-Dev
AutomationRole-Prod

Use SCPs to:

•         Block unsafe actions in Prod
•         Enforce approval steps

Integration with Maintenance Windows

Automation can be:

•         Triggered inside a Maintenance Window
•         Used as the task itself

Why SSM Automation Matters

• Maintenance Windows = When
• Automation = How

This enables:

•         Time-boxed
•         Multi-step
•        Safe change execution

Example:

Automation + Patch Manager (Enterprise Pattern)

Instead of:

•         One-step patch execution

Use:

•         Automation runbook wrapping Patch Manager

Benefits

•         Pre/post checks
•         Service coordination
•         Canary patching
•         Custom reboot logic

Approval Gates (Change Control)

• Automation supports manual approval steps.

# yaml

- name: Approval

  action: aws:approve

  inputs:

    Message: "Approve production patching"

    Approvers:

      - arn:aws:iam::accountID:role/ChangeManager

# This aligns directly with:

•         ITIL
•         SOX
•         Regulated change models

Event-Driven Automation

Automation executions can be triggered by:

•         EventBridge
•         CloudWatch alarms
•         Security Hub findings
•         Config drift detection

Example:

•         Unencrypted volume detected → Automation runbook remediates

NB:

• This is auto-remediation at scale.

Logging, Audit & Compliance

Every Automation execution records:

•         Who started it
•         What role was used
•         What steps ran
•         Inputs / outputs
•         Success or failure

Stored in:

•         SSM Automation history
•         CloudTrail
•         CloudWatch Logs

NB:

• This produces forensic-grade audit evidence.

Enterprise Use Cases

1. Rolling Production Patching

•         Canary → batch → full rollout

2. AMI Golden Image Pipelines

•         Patch → harden → test → tag

3. Incident Remediation

•         Scale ASG
•         Replace unhealthy instances

4. Security Auto-Fix

•         Close public S3 buckets
•         Rotate credentials
•         Apply missing patches

Common Anti-Patterns

Anti-Pattern	Why It Fails
Shell scripts only	No state, no rollback
Over-privileged roles	Compliance risk
No approval gates	Change violations
Manual prod execution	Audit gaps

When to Use Automation vs Alternatives

Use Case	Best Tool
One-off commands	Run Command
Scheduled ops	Maintenance Windows
Complex workflows	Automation
CI/CD deploys	CodePipeline
Event remediation	Automation + EventBridge

Final thoughts

• SSM Automation is:
•         A workflow engine for operations
•         Built for safety, scale, and auditability
•         A cornerstone of DevSecOps maturity
• For advanced AWS environments.
• No production changes happen without Automation.