Terraform state explained!!!

By – christophchamp

• Terraform keeps the remote state of the infrastructure
• It stores it in a file called terraform.tfstate
• There is also a backup of the previous state in terraform.tfstate.backup
• When you execute terraform apply, a new terraform.tfstate and backup is created
• This is how Terraform keeps track of the remote state
  • If the remote state changes and you run terraform apply again, Terraform will make changes to meet the correct remote state again.
  • E.g., you manually terminate an instance that is managed by Terraform, after you run terraform apply, it will be started again.
• You can keep the terraform.tfstate in version control (e.g., git).
  • This will give you a history of your terraform.tfstate file (which is just a big JSON file)
  • This allows you to collaborate with other team members (however, you can get conflicts when two or more people make changes at the same time)
• Local state works well with simple setups. However, if your project involves multiple team members working on a larger setup, it is better to store your state remotely
  • The Terraform state can be saved remotely, using the backend functionality in Terraform.
  • Using a remote store for the Terraform state will ensure that you always have the latest version of the state.
  • It avoids having commit and push the terraform.tfstate file to version control.
  • However, make sure the Terraform remote store you choose supports locking! (note: both s3 and consul support locking)
• The default state is a local backend (the local Terraform state file)
• Other backends include:
  • AWS S3 (with a locking mechanism using DynamoDB)
  • Consul (with locking)
  • Terraform Enterprise (the commercial solution)
• Using the backend functionality has definite benefits:
  • Working in a team, it allows for collaboration (the remote state will always be available for the whole team)
  • The state file is not stored locally and possible sensitive information is only stored in the remote state
  • Some backends will enable remote operations. The terraform apply will then run completely remotely. These are called enhanced backends.
• There are two steps to configure a remote state:
  1. Add the back code to a .tf file
  2. Run the initialization process

Rajesh Kumar

I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.

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