Terraform_Workspace || Lab

Step-01: Introduction

• We are going to create 2 more workspaces (dev,qa) in addition to default workspace

• Primarily we would name security group to be unique for each workspace

• In the same way for EC2 VM Instance Name tag.

• Master the below listed terraform workspace commands

  • terraform workspace show
  • terraform workspace list
  • terraform workspace new
  • terraform workspace select
  • terraform workspace delete

Step-02: Update terraform manifests to support multiple workspaces

• What is ${terraform.workspace}? - It will get the workspace name
• Popular Usage-1: Using the workspace name as part of naming or tagging behavior
• Popular Usage-2: Referencing the current workspace is useful for changing behavior based on the workspace. For example, for non-default workspaces, it may be useful to spin up smaller cluster sizes.

# 1: Security Group Names
  name        = "vpc-ssh-${terraform.workspace}"
  name        = "vpc-web-${terraform.workspace}"  

# 2: For non-default workspaces, it may be useful to spin up smaller cluster sizes.
  count = terraform.workspace == "default" ? 2 : 1  
This will create 2 instances if we are in default workspace and in any other workspaces it will create 1 instance

# 3: EC2 Instance Name tag
    "Name" = "vm-${terraform.workspace}-${count.index}"

# 4: Outputs
  value = aws_instance.my-ec2-vm.*.public_ip
  value = aws_instance.my-ec2-vm.*.public_dns    
You can create a list of all of the values of a given attribute for the items in the collection with a star. For instance, aws_instance.my-ec2-vm.*.id will be a list of all of the Public IP of the instances.  

Step-03: Create resources in default workspaces

• Default Workspace: Every initialized working directory has at least one workspace.
• If you haven't created other workspaces, it is a workspace named default
• For a given working directory, only one workspace can be selected at a time.
• Most Terraform commands (including provisioning and state manipulation commands) only interact with the currently selected workspace.

# Terraform Init
terraform init 

# List Workspaces
terraform workspace list

# Output Current Workspace using show
terraform workspace show

# Terraform Plan
terraform plan -var-file="default.tfvars"
Observation: This should show us two instances based on the statement in EC2 Instance Resource "count = terraform.workspace == "default" ? 2 : 1" because we are creating this in default workspace

# Terraform Apply
terraform apply -var-file="default.tfvars"

# Verify
Verify the same in AWS Management console
Observation: 
1) Two instances should be created with name as "vm-default-0, vm-default-1")
2) Security Groups should be created with names as "vpc-ssh-default, vpc-web-default)
3) Observe the outputs on CLI, you should see list of Public IP and Public DNS 

Step-04: Create New Workspace and Provision Infra

# Create New Workspace
terraform workspace new dev

# Verify the folder
tree terraform.tfstate.d 
   |_ dev

# Terraform Plan
terraform plan -var-file="dev.tfvars"
Observation:  This should show us creating only 1 instance based on statement "count = terraform.workspace == "default" ? 2 : 1" as we are creating this in non-default workspace named dev

# Terraform Apply
terraform apply -var-file="dev.tfvars"

# Verify Dev Workspace statefile
cd terraform.tfstate.d/dev
ls
Observation: You should fine "terraform.tfstate" in "current-working-directory/terraform.tfstate.d/dev" folder

# Verify EC2 Instance in AWS mgmt console
Observation:
1) Name should be with "vm-dev-0"
2) Security Group names should be as "vpc-ssh-dev, vpc-web-dev"

Step-05: Switch workspace and destroy resources

• Switch workspace from dev to default and destroy resources in default workspace

# Show current workspace
terraform workspace show

# List Worksapces
terraform workspace list

# Workspace select
terraform workspace select default

# Delete Resources from default workspace
terraform destroy 

# Verify
1) Verify in AWS Mgmt Console (both instances and security groups should be deleted)

Step-06: Delete dev workspace

• We cannot delete "default" workspace
• We can delete workspaces which we created (dev, qa etc)

# Delete Dev Workspace
terraform workspace delete dev
Observation: Workspace "dev" is not empty.
Deleting "dev" can result in dangling resources: resources that
exist but are no longer manageable by Terraform. Please destroy
these resources first.  If you want to delete this workspace
anyway and risk dangling resources, use the '-force' flag.

# Switch to Dev Workspace
terraform workspace select dev

# Destroy Resources
terraform destroy -auto-approve

# Delete Dev Workspace
terraform workspace delete dev
Observation:
Workspace "dev" is your active workspace.
You cannot delete the currently active workspace. Please switch
to another workspace and try again.

# Switch Workspace to default
terraform workspace select default

# Delete Dev Workspace
terraform workspace delete dev
Observation: Successfully delete workspace dev

# Verify 
In AWS mgmt console, all EC2 instances should be deleted

Step-07: Clean-Up Local folder

# Clean-Up local folder
rm -rf .terraform*
rm -rf terraform.tfstate*

References

• Terraform Workspaces
• Managing Workspaces