DevOps Classroomnotes 29/Oct/2022

Terraform Provisioning

  • Terraform provisioning is used to perform extra operations after resources are created.
  • That could be generally executing scripts Refer Here
  • There are three provisioners
  • To connect to the remote instance we need connection Refer Here
  • Lets install apache server in the ec2 instance created. The commands that needs to be executed on the remote are
sudo apt update
sudo apt install apache2 -y
  • Terraform provisioner will be run only when the resource is created.
  • Refer Here for the changes done to install nginx and add url as output
  • Lets make changes in remote-exec inline Refer Here and try to perform terraform apply. Terraform will not consider the changes in remote-exec as desired state, so nothing will be executed.
  • Provisoner without a resource can be used to solve this problem
  • Lets add a null provider Refer Here
  • In the null resource create a triggers which maps to certain input from the user which triggers script execution
  • Refer Here for the changes.

Terraform state

  • As of now the terraform state is maintained in the local folder. when we try to execute the same infra from different system it also generates a new state file which means new resources will be provisioned again.
  • solution for this is provided by terraform backends.
  • Refer Here for official docs
  • Backend is location where your state file gets stored.
  • Default backend is local. This is the reason why .tfstate is shown in local folder where we have templates.
  • Lets us s3 as backend

Terraform backend s3

  • The state file gets stored in aws s3.
  • But terraform s3 backend doesnot support locking. To perform locking terraform expects a dynamo db table to be created
  • Refer Here for the official docs
  • After adding backend information execute terraform init
  • Refer Here for the changeset
  • Ensure you have terraform installed and configure on two nodes/systems
  • For the purposes of understand. screen shots with git bash is user2 and screenshots with powershell is user1
  • User1 execute terraform apply
  • User2 also executes terraform apply

Terraform Workspaces

  • Terraform workspaces allows us to create locking per workspace.
  • Each workspace can be considered as one environment
  • Refer Here for official docs and Refer Here to manage workspaces
  • Refer Here for cli options
  • Create multiple workspaces depending on environments
  • Commands
terraform workspace --help


  • Findout how to configure terraform aws provider to create resources in two regions

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