Terraform v1

courses/terraform/README.md

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+# Terraform
+
+## YouTube
+
+## Summary
+
+Terraform consists of:
+
+- Providers: Allow connecting the configuration to the cloud provider API
+- `*.tfstate` file: It stores the current state of our architecture. Must be encrypted.
+
+Important Commands
+
+- `terraform init`: Add required providers plugins code
+- `terraform plan`: Check what will change to our system
+- `terraform apply`: Apply the changes
+- `terraform destroy`: Delete the whole system.
+
+Every resource consists of like this
+
+```terraform
+resource "<provider_name>_<resource_type>" "<resource_name>" {
+  <property> = <property_value>
+}
+```
+
+We can reference data from one resource into another resouce
+
+```
+vpc_id = <provider_name>_<resource_type>.<resource_name>.<property_key>
+```
+
+Terraform gives support to concepts similar to other programming languages like:
+
+- Variables
+- Outputs
+- Conditionals & Loops
+- Modules
+
+### Variables
+
+To create a variable
+
+```tf
+variable "instance_type" {
+  description = "just a description for the variable"
+  type        = string   # also boolean & number
+  default     = "default value"
+  sensitive   = true     # in case of sensitive data to hide from logs
+}
+```
+
+to set the varibles we can
+
+- Manually entry in Terraform plan/apply
+- Inside the `local` block
+- `TF_VAR_<name>` environment variables
+- `*.tfvars` files
+- Command Line `-var` and `-var-file`
+
+Types can be
+
+- Primative: string, number, bool
+- Complex: list, set, mao, object, tuple
+
+### Outputs
+
+They are like the return of functions, when we run a certain resource, we get the object returns and we can reference them using the `output` block
+
+```tf
+output "instance_ip_addr" {
+  value = aws_instance.server.private_ip
+}
+```
+
+### Modules
+
+They are used to abstract creating multiple resources into a single module. They can be hosted on many places like:
+
+- Local paths
+- Terraform Repository
+- Git
+- HTTP Urls
+- S3 Buckets
+
+```tf
+module "module_name" {
+  source "../webapp" # path to the module root directory
+
+  # Input variables
+  bucket_name = "webapp-bucket"
+  domain      = "example.com"
+}
+```
+
+### Workspaces
+
+Terraform has workspaces to manage multiple environments
+
+- `terraform workspace list`: List available workspaces
+- `terraform workspace new <env_name>`: Create a new workspace
+- `terraform workspace select <env_name>`: Select a workspace
+
+Available variable is `terraform.workspace` for the current workspace
+
+We can also use files and directories structure to manage workspaces instead of using terraform workspaces and it's more recommended.
+
+## Resources
+
+- [Complete Terraform Course - From BEGINNER to PRO! (Learn Infrastructure as Code)](https://www.youtube.com/watch?v=7xngnjfIlK4)