Remote State and State Locking with Terraform are essential concepts that ensure safe, scalable, and collaborative infrastructure automation. Whether you’re managing cloud resources alone or in a team, understanding how Terraform handles its state files—and how to secure them—is critical to maintaining infrastructure consistency and preventing disasters.
In this guide, you’ll learn what Terraform state is, why local state is limited, and how remote backends and state locking solve serious collaboration issues.
Table of Contents
What Is Terraform State?
When Terraform applies a configuration, it generates a state file to keep track of your infrastructure. This file records details like resource IDs, IP addresses, dependency metadata, and more.
By default, this file is called terraform.tfstate and is saved locally in the working directory. It helps Terraform:
- Map real-world infrastructure to your configuration
- Track resource dependencies for correct ordering
- Optimize performance during large operations
- Maintain a consistent source of truth across executions
Limitations of Local State Storage
While local state works for solo developers, it quickly becomes problematic in team settings.
Problem 1: No Collaboration Support
Local state lives on one machine. If another team member needs to provision infrastructure, they won’t have access to the latest state—unless it’s shared manually or via a version control system like Git.
Problem 2: Security Risks
State files often contain sensitive data such as:
- IP addresses
- SSH key names
- Initial credentials for services like RDS or EC2
Storing this file in a Git repository—even a private one—can lead to unintentional leaks.
Problem 3: No State Locking in Git
Version control systems like Git do not support state locking. This means multiple users can unknowingly apply changes at the same time, risking state file corruption or resource destruction.
What Is State Locking?
State locking is Terraform’s built-in mechanism that prevents concurrent operations on the same state file.
For example, if you run terraform apply in one terminal, and try to run it again from another terminal before the first finishes, Terraform will block the second operation. This ensures the state file isn’t updated simultaneously.
State locking is automatic when working locally. But again, this only protects operations initiated from the same machine. It doesn’t work across multiple team members unless a shared backend is used.
Why You Should Use Remote State with Terraform
To overcome the issues of local state, Terraform supports storing state remotely in backends. Remote state storage:
- Enables collaboration
- Offers automatic state loading and saving
- Supports state locking in many cases
- Provides encryption at rest and in transit
- Keeps your state file secure and accessible
Popular remote backends include:
- AWS S3 (often combined with DynamoDB for locking)
- Terraform Cloud
- Google Cloud Storage
- Azure Blob Storage
- HashiCorp Consul
How Remote State Solves Real Problems
Let’s walk through a real-world scenario.
Example: Collaboration Chaos Without Remote State
Imagine Developer A deploys an S3 bucket and pushes the state file to Git. Developer B pulls the repo and also runs Terraform to make changes. If both aren’t working with the same state version, one could overwrite the other’s changes—or worse, destroy resources accidentally.
This scenario highlights the need for a shared, real-time, and locked state file.
Solution: Secure Remote Storage + Locking
With a backend like AWS S3 and DynamoDB:
- The state file is stored in a shared S3 bucket
- State locking is handled through DynamoDB
- Only one Terraform operation can run at a time
- All developers access the latest state automatically
No more manual syncing. No accidental overwrites.
Best Practices for Remote State Management
- Always use encryption – Ensure your remote backend encrypts data at rest and in transit.
- Use versioning – Enable versioning in S3 to roll back to a previous state if needed.
- Combine with state locking – For S3, use DynamoDB to lock the state during operations.
- Avoid committing state to Git – Add
terraform.tfstateand.terraformdirectories to.gitignore. - Use workspaces for environments – Separate dev, staging, and production environments cleanly.
Conclusion
Understanding Remote State and State Locking with Terraform is critical for building safe and scalable infrastructure. While local state works for quick tests or individual developers, it simply doesn’t scale in team environments or production use.
By switching to a remote backend like AWS S3 (with optional DynamoDB locking), you gain security, collaboration, and confidence that your infrastructure won’t break from concurrent updates or outdated state files.
Take the time to set up remote state early—it’s a powerful step toward professional-grade Infrastructure as Code.
Frequently Asked Questions (FAQs)
1. What happens if multiple people apply Terraform at the same time?
Without remote state and locking, simultaneous operations can corrupt the state file. Use a backend like S3 with locking support to prevent this.
2. Is storing state in Git safe?
No. Terraform state files can contain sensitive infrastructure data. Always exclude them from version control.
3. Can I use remote state without locking?
Yes, but it’s not recommended. Without locking, you risk data races and inconsistent state updates during concurrent applies.
4. Which backends support state locking?
Backends like AWS S3 (with DynamoDB), Terraform Cloud, and Consul support locking. Choose one based on your cloud platform and team needs.
5. What is the difference between local and remote state?
Local state is stored on your machine, while remote state resides in shared cloud storage. Remote state allows team collaboration and enables locking for safety.