Implementing Distributed State Locking

Table of Contents

1. Challenge

   Simulate and Identify Race Conditions by Triggering Simultaneous State Access Attempts Across Different Terminal Sessions

   • Initiate a long-running terraform apply in one terminal session to hold the state lock.
   • Attempt a concurrent plan from a second terminal session to trigger a lock contention error.
   • Analyze the error output and DynamoDB lock record to identify the Lock ID, holder, and operation type.
2. Challenge

   Resolve Lock Contention Scenarios by Manually Identifying and Clearing Stuck Locks Using the Unique Lock ID

   • Simulate an orphaned lock by force-terminating a Terraform apply mid-execution.
   • Extract the stuck Lock ID from the DynamoDB table and release it using terraform force-unlock.
   • Verify state integrity by running terraform refresh and confirming zero drift with a plan.
3. Challenge

   Integrate Distributed Locking Logic into an Automated CI/CD Pipeline to Ensure Safe, Serializable Infrastructure Updates

   • Examine and run a pre-built CI/CD simulation script that mimics a GitHub Actions workflow.
   • Use the -lock-timeout CLI flag so pipelines retry on transient lock contention.
   • Demonstrate the -lock=false flag for read-only operations and document why it is dangerous for writes.