How to use Terraform to create a Redis instance in GCP

In this guide, we will build a Redis instance in Google cloud platform using terraform. Terraform allows you to develop cloud infrastructure by automating repetitive tasks.

Creating a Redis cluster in the console can be tiring, especially if you have to create multiple instances with different parameters such as node types, node sizes etc. Terraform was created to solve that problem. It allows you to have the instructions as code that can be used to plan, deploy, modify, and destroy the clusters programmatically.

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Requirements

You need the following to proceed

A Google Project – GCP organizes resources into projects. Create one now in the GCP console and make note of the project ID.
Enable Google Compute Engine for your project in the GCP console. Make sure to select the project you are using to follow this tutorial and click the “Enable” button.
A GCP service account key: Create a service account key to enable Terraform to access your GCP account. When creating the key, use the following settings:
Select the project you created in the previous step.
Click “Create Service Account”.
Give it any name you like and click “Create”.
For the Role, choose “Project -> Editor”, then click “Continue”.
Skip granting additional users access, and click “Done”.

After you create your service account, download your service account key.

Select your service account from the list.
Select the “Keys” tab.
In the drop down menu, select “Create new key”.
Leave the “Key Type” as JSON.
Click “Create” to create the key and save the key file to your system.

You also need to enable the redis api. You can either use the console or use this gcloud command:

gcloud services enable redis.googleapis.com

Step 1 – Downloading and installing terraform

Terraform is available as a binary for most distributions. Get the latest binary and download instructions from terraform downloads page here.

Step 2 – Adding the Project code

In this section we will create the files that will contain the code for our resources. First you need to create a directory and switch to it. In your terminal use these commands:

mkdir gcp-redis
cd gcp-redis

First we will have to specify the providers. Terraform relies on plugins called “providers” to interact with cloud providers, SaaS providers, and other APIs.

Terraform configurations must declare which providers they require so that Terraform can install and use them. Additionally, some providers require configuration (like endpoint URLs or cloud regions) before they can be used.

This is the main.tf where we define the google provider that we will use and we are also specifying the specific versions. We are also defining some locals that we can reuse.

A local value assigns a name to an expression, so you can use the name multiple times within a module instead of repeating the expression. Local values are like a function’s temporary local variables.

locals {
  env              = "dev"
  project          = "citizix"
  credentials_path = "./gcp-credentials.json"
  region           = "europe-west1"
}

terraform {
  required_providers {
    google = {
      source  = "hashicorp/google"
      version = ">=4.20.0, < 5.0.0"
    }
  }
}

provider "google" {
  credentials = file(local.credentials_path)

  project = "citizix-prj"
  region  = local.region
}

Creating the redis instance

Use this code to create the redis instance

locals {
  redis_name = "${local.env}-${local.project}-redis"
}

resource "google_redis_instance" "redis" {
  name           = local.redis_name
  display_name   = "${local.redis_name} created by Terraform"
  memory_size_gb = 1
  region         = local.region
  location_id    = "${local.region}-a"
  redis_version  = "REDIS_6_X"
}

output "redis_host" {
  value = google_redis_instance.redis.host
}

output "redis_port" {
  value = google_redis_instance.redis.port
}

output "redis_current_location_id" {
  value = google_redis_instance.redis.current_location_id
}

Step 4 – Planning and applying changes

To apply the changes, do the following

First initialize terraform to download required dependencies and plugins.

terraform init

Then validate to ensure that you have valid code without errors.

terraform validate

Then plan to confirm that the changes being introduced are what is expected.

terraform plan -out tf.plan

Finally apply to create resources in gcp.

terraform apply - tf.plan

To apply with no prompt

terraform apply -auto-approve tf.plan

If you no longer need the changes you can destroy with this. You can add -auto-approve if you do not want to be prompted.

terraform destroy

Step 5 – Connecting to the Redis Instance

Ensure that you are connected to the cloud console from the terminal. You can either use gcloud or postgres client to access the instance.

Then use gcloud command to connect:

gcloud redis instances list --limit=5 --region=europe-west6

Conclusion

We were able to use terraform to create a Redis instance in gcp. This allows us to create and destroy resources easily at the same time bringing in benefits of having infrastructure as code.