# Error: Error acquiring the state lock: ConditionalCheckFailedException: The conditional request failed (Service: DynamoDb, Status Code: 400)

- **ID:** `cicd/terraform-lock-acquire-timeout`
- **Domain:** cicd
- **Category:** runtime_error
- **Error Code:** `LOCK_ACQUIRE_TIMEOUT`
- **Verification:** ai_generated
- **Fix Rate:** 85%

## Root Cause

Terraform state lock acquisition fails due to concurrent operations on the same state file, typically when multiple CI jobs or team members run terraform apply simultaneously against the same backend (e.g., DynamoDB table).

## Workarounds

1. **Use terraform force-unlock <LOCK_ID> after verifying no other operation is running. First, identify lock ID: terraform force-unlock -force <LOCK_ID>. Example: terraform force-unlock -force 12345-abcde-67890-fghij** (80% success)
   ```
   Use terraform force-unlock <LOCK_ID> after verifying no other operation is running. First, identify lock ID: terraform force-unlock -force <LOCK_ID>. Example: terraform force-unlock -force 12345-abcde-67890-fghij
   ```
2. **Implement a mutex in CI pipeline using a dedicated lock mechanism (e.g., GitLab CI resource_group or GitHub Actions concurrency) to prevent concurrent terraform apply runs. Example GitHub Actions: concurrency: group: terraform-deploy cancel-in-progress: false** (95% success)
   ```
   Implement a mutex in CI pipeline using a dedicated lock mechanism (e.g., GitLab CI resource_group or GitHub Actions concurrency) to prevent concurrent terraform apply runs. Example GitHub Actions: concurrency: group: terraform-deploy cancel-in-progress: false
   ```

## Dead Ends

- **Delete the lock file manually from S3 or DynamoDB to force unlock** — Manual deletion can corrupt state if another operation is in progress, leading to data loss or inconsistent state. Terraform's force-unlock should be used instead. (60% fail)
- **Set parallelism=1 in terraform config to serialize all operations** — This only affects resource provisioning parallelism, not state lock contention from multiple processes; it does not prevent concurrent terraform apply commands. (90% fail)