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DevOps Intermediate 122 views

Terraform State Locked

Another Terraform operation is already running and has locked the state file.

Explanation

Terraform State Locked occurs when you try to run a Terraform operation (plan, apply, destroy) while another operation is already in progress. Terraform uses a state lock to prevent concurrent modifications that could corrupt the state file. This typically happens with remote state backends (S3, Consul, etc.) when two people or CI/CD pipelines run Terraform simultaneously, or when a previous Terraform run was interrupted (Ctrl+C, network failure) without releasing the lock.

Common Causes

  • Another Terraform run in progress
  • Previous run was interrupted
  • CI/CD pipeline running concurrent applies
  • Network failure during apply
  • Manual state modification

Solution

First verify no other operation is actually running. If safe to proceed, force-unlock the state: terraform force-unlock LOCK_ID. Get the lock ID from the error message. Use terraform force-unlock -help to see options. For team environments, use Terraform Cloud or Atlantis for proper locking and workflow. Set up proper CI/CD pipeline to serialize Terraform runs. Use workspaces for parallel development. Check the state backend for stale locks. Always use terraform plan before apply to review changes.

Code Example 

# Error: Error acquiring the state lock
# Error message: ConditionalCheckFailedException

# Get the lock ID from the error message
# Lock Info:
#   ID:        a1b2c3d4-e5f6-7890-abcd-ef1234567890
#   Path:      my-bucket/terraform.tfstate
#   Operation: OperationTypeApply

# Check if someone else is running Terraform
# Ask your team before force-unlocking!

# Force unlock (use with caution)
terraform force-unlock a1b2c3d4-e5f6-7890-abcd-ef1234567890

# For S3 backend, check DynamoDB table
aws dynamodb scan --table-name terraform-locks

# Delete stale lock manually (DynamoDB)
aws dynamodb delete-item \
    --table-name terraform-locks \
    --key '{"LockID": {"S": "my-bucket/terraform.tfstate"}}'

# Preventive: use Terraform Cloud/Enterprise
# for proper state locking and team workflow

Error Information

Language

bash

Framework

terraform

Difficulty

Intermediate

Views

122

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