AWS Systems Manager Run Command is a powerful feature that enables administrators to remotely execute commands across multiple EC2 instances and on-premises servers at scale, eliminating the need for SSH or RDP connections. This capability is essential for SysOps Administrators managing large infra…AWS Systems Manager Run Command is a powerful feature that enables administrators to remotely execute commands across multiple EC2 instances and on-premises servers at scale, eliminating the need for SSH or RDP connections. This capability is essential for SysOps Administrators managing large infrastructure deployments.
Run Command operates through the SSM Agent, which must be installed and running on target instances. The agent communicates with the Systems Manager service, allowing secure command execution through IAM-based authentication and authorization.
Key features include:
**Document-Based Execution**: Commands are defined in SSM Documents (JSON or YAML format) that specify the actions to perform. AWS provides pre-built documents for common tasks like installing software, running shell scripts, or configuring Windows settings.
**Targeting Options**: Administrators can target instances using instance IDs, tags, or resource groups, enabling flexible deployment strategies across development, staging, and production environments.
**Rate Control**: You can control execution by setting concurrency limits (how many instances run simultaneously) and error thresholds (stopping execution if too many instances fail).
**Output and Logging**: Command output can be stored in S3 buckets or sent to CloudWatch Logs for monitoring and troubleshooting. This provides complete audit trails for compliance requirements.
**Integration with Other Services**: Run Command integrates with EventBridge for automation triggers, SNS for notifications, and can be invoked through the AWS CLI, SDKs, or console.
**Security Benefits**: Since Run Command uses the Systems Manager service endpoint, instances do not require open inbound ports. All communications are encrypted, and actions are logged in CloudTrail.
Common use cases include patch management, software installation, configuration updates, and running diagnostic scripts. For the SysOps exam, understanding how to troubleshoot SSM Agent connectivity, configure proper IAM roles, and interpret command execution results is crucial for operational excellence.
Systems Manager Run Command - Complete Guide
What is Systems Manager Run Command?
AWS Systems Manager Run Command is a feature that allows you to remotely and securely manage the configuration of your managed instances at scale. It enables you to execute commands across multiple EC2 instances or on-premises servers simultaneously, eliminating the need to SSH or RDP into each server individually.
Why is Run Command Important?
Run Command is critical for several reasons:
• Scalability: Execute commands on hundreds or thousands of instances simultaneously • Security: No need to open inbound SSH or RDP ports; uses IAM for access control • Auditability: All command executions are logged in CloudTrail and can be sent to S3 or CloudWatch • Automation: Integrates with EventBridge, Lambda, and Step Functions for automated workflows • Cost-effective: No additional charge for using Run Command itself
How Does Run Command Work?
1. Prerequisites: Instances must have the SSM Agent installed and running, proper IAM role attached (AmazonSSMManagedInstanceCore policy), and outbound connectivity to Systems Manager endpoints
2. Documents: Run Command uses SSM Documents (also called Command Documents) that define the actions to perform. AWS provides pre-built documents like: • AWS-RunShellScript - For Linux commands • AWS-RunPowerShellScript - For Windows PowerShell commands • AWS-UpdateSSMAgent - Updates the SSM agent • AWS-ConfigureAWSPackage - Installs or uninstalls AWS packages
3. Targeting: You can target instances using: • Instance IDs • Tags (e.g., Environment=Production) • Resource Groups • All managed instances
4. Execution: Commands are sent through the Systems Manager service to the SSM Agent on target instances. Results are captured and stored.
5. Rate Control: You can set concurrency (how many instances run simultaneously) and error thresholds (stop execution after X failures)
Key Features to Remember:
• Output Storage: Command output can be stored in S3 buckets or CloudWatch Logs • Notifications: SNS notifications can be configured for command status updates • Timeout: Default timeout is 3600 seconds (1 hour); can be customized • Parameters: Documents can accept parameters for flexible execution • Cross-account: Can execute commands across multiple AWS accounts using resource data sync
Exam Tips: Answering Questions on Systems Manager Run Command
1. When to Choose Run Command: Select Run Command when questions mention executing commands on multiple instances, patching, configuration management, or administrative tasks at scale
2. SSM Agent Requirement: If a question mentions instances not appearing in Systems Manager, think about SSM Agent installation, IAM roles, or network connectivity issues
3. Security Benefits: When questions ask about secure management of instances or reducing attack surface, Run Command is often the answer because it eliminates the need for open SSH/RDP ports
4. Comparison with Other Services: • Use Run Command for ad-hoc or scheduled command execution • Use State Manager for ensuring consistent configuration state • Use Automation for complex multi-step workflows
5. Rate Control Questions: Remember that concurrency controls how many instances execute at once, while error threshold controls when to stop execution based on failures
6. Hybrid Environment: Run Command works on both EC2 instances and on-premises servers with proper activation
7. Output Limitations: Console shows truncated output (first 48,000 characters); for full output, configure S3 or CloudWatch Logs
8. IAM Permissions: Users need appropriate IAM permissions to send commands, and instances need the SSM managed policy attached to their instance profile
9. Cost Considerations: Run Command itself is free; you only pay for resources used (S3 storage, CloudWatch Logs, etc.)