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Container Action

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What is a Container Action?​

A Container Action allows you to execute commands inside a container during chaos experiment execution. This provides powerful capabilities to:

  • Execute custom commands in containerized environments
  • Perform application-specific operations during experiments
  • Run validation or diagnostic commands
  • Interact with containerized applications and services
  • Implement custom setup or cleanup operations
  • Execute scripts or binaries available in container images

When to Use Container Actions​

Container Actions are particularly valuable in the following scenarios:

Application Validation​

  • Health Checks: Execute application-specific health check commands
  • State Verification: Validate application state during chaos events
  • Data Validation: Check data consistency within containers
  • Process Monitoring: Verify that critical processes are running

System Operations​

  • Configuration Changes: Apply configuration changes during experiments
  • Service Restarts: Restart services or processes within containers
  • Cache Operations: Clear caches or perform cache-related operations
  • Log Collection: Gather application logs for analysis

Environment Setup/Cleanup​

  • Pre-experiment Setup: Prepare the containerized environment before chaos
  • Post-experiment Cleanup: Clean up resources after experiment completion
  • Test Data Management: Set up or tear down test data
  • State Preparation: Configure specific application states

Diagnostic Operations​

  • Network Diagnostics: Run network connectivity tests from within containers
  • Resource Checks: Monitor resource usage from inside containers
  • Dependency Validation: Verify connectivity to dependent services
  • Performance Metrics: Collect application-specific performance data

How to configure a Container Action​

Step 1: Create a New Action​

  1. Navigate to your Probes & Actions and go to the Actions tab
  2. Click New Action and select Container from the dropdown

create container action

Step 2: Configure Metadata​

Configure the following parameters for your container action:

  • Name: Provide a descriptive name for the container action
  • Description (optional): Add a description to explain the action's purpose
  • Tags (optional): Add tags for better organization and filtering
  • Infrastructure Type: Select the target infrastructure (Kubernetes)

configure container action

Step 3: Configure Action Properties​

In the Action Properties section, configure the container and command details:

  • Container Image: Specify the container image to use (e.g., bitnami/kubectl:latest, busybox:latest, alpine:latest)
  • Command: Specify the command to execute inside the container as an array (e.g., /bin/sh, -c)
    • You can add multiple command arguments by clicking the + Add button
  • Arguments: Provide the actual command or script to execute (e.g., echo "Hello World")
  • Environment Variables (optional): Add environment variables as key-value pairs
    • Click + Add to add new environment variables
  • Namespace: Specify the Kubernetes namespace (default: default)
  • Image Pull Policy: Define when to pull the image (IfNotPresent, Always, Never)

container action properties

Step 4: Configure Advanced Settings (Optional)​

Configure advanced settings as needed:

Advanced Configuration​

  • Service Account Name: Kubernetes service account to use
  • Image Pull Secrets: Secrets for private registries
  • Labels and Annotations: Custom metadata for the action container
  • Node Selector: Node selection constraints
  • Tolerations: Allow scheduling on nodes with matching taints
  • Node Affinity: Required or preferred node affinity rules
  • Resource Limits: Set memory and CPU limits (e.g., 512Mi, 500m)
  • Resource Requests: Set memory and CPU requests (e.g., 256Mi, 100m)

Volumes​

  • Add volumes to mount into the action container with volume name, mount path, and volume source

Volume Mounts​

  • Specify additional volume mounts with name, mount path, and optional sub path

Security Configuration​

  • Host Network, HostPID, Host IPC: Use host namespaces
  • Allow Privilege Escalation: Allow gaining more privileges
  • Read Only Root Filesystem: Mount root filesystem as read-only
  • Privileged: Run in privileged mode
  • Run As Non Root: Ensure non-root execution
  • Run as user and Run as group: Specify user and group IDs
  • FS Group: Filesystem group ID for volume ownership

Step 5: Configure Run Properties​

Configure the execution behavior:

  • Timeout: Maximum time for action execution (e.g., 10s)
  • Interval: Time between successive executions (e.g., 2s)
  • Max Retries: Number of retry attempts (e.g., 1)
  • Initial Delay: Delay before first execution (e.g., 5s)

container action run properties

Step 6: Position the Action​

Place the container action at the appropriate point in your experiment workflow:

  • Pre-experiment: Setup or validation before chaos injection
  • Mid-experiment: Operations or validation during chaos
  • Post-experiment: Cleanup or final validation after chaos
  • Between Phases: Transition logic between different experiment phases

Next Steps​