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Kubernetes Terraforming on Linode: Linode + Terraform + Kubernetes = Cloud Nirvanaby@priya11
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Kubernetes Terraforming on Linode: Linode + Terraform + Kubernetes = Cloud Nirvana

by Priya KumariJanuary 23rd, 2023
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Together, Terraform and Kubernetes are a winning combination because they allow for the automated deployment and management of a Kubernetes cluster on Linode infrastructure. Terraform can be used to provision and manage the underlying infrastructure resources, such as virtual machines and networks, while Kubernetes can be used to manage and scale the containerized applications running on the cluster. This allows for a more efficient and streamlined deployment process, as well as improved reliability and scalability of the cluster. Linode infrastructure leverages underlying resources that are used to deploy and run a Kubernetes cluster. These resources include virtual machines, storage, and networking resources. By using Terraform, these resources can be provisioned and managed as code, making it easier to automate the deployment process and improve the reliability and scalability of the cluster. The Linode infrastructure also provides a range of features, such as multiple data centers, high availability, and advanced networking options that are beneficial for Kubernetes clusters.
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Introduction


Terraforming Kubernetes on Linode allows for automated and efficient deployment and management of Kubernetes clusters on Linode's infrastructure. By using Terraform, infrastructure can be provisioned and managed as code, making it easier to version control and automate the deployment process. This improves the overall reliability and scalability of the Kubernetes cluster on Linode.


Linode is a cloud hosting provider that offers virtual private servers (VPS) and other cloud-based services. It allows users to easily provision and manage virtual machines, storage, and networking resources. The Linode infrastructure is built on top of a network of data centers located around the world, providing users with the ability to deploy resources in multiple geographic locations.


Kubernetes is an open-source container orchestration system that is used to manage and scale containerized applications. It provides features such as automatic scaling, service discovery, and self-healing capabilities.


Terraform, on the other hand, is a tool used for provisioning and managing infrastructure as code. It allows for the creation and management of infrastructure resources, such as virtual machines and networks, in a consistent and repeatable way.


Together, Terraform and Kubernetes are a winning combination because they allow for the automated deployment and management of a Kubernetes cluster on Linode infrastructure.


Terraform can be used to provision and manage the underlying infrastructure resources, such as virtual machines and networks, while Kubernetes can be used to manage and scale the containerized applications running on the cluster. This allows for a more efficient and streamlined deployment process, as well as improved reliability and scalability of the cluster.


Linode infrastructure leverages underlying resources that are used to deploy and run a Kubernetes cluster. These resources include virtual machines, storage, and networking resources. By using Terraform, these resources can be provisioned and managed as code, making it easier to automate the deployment process and improve the reliability and scalability of the cluster. The Linode infrastructure also provides a range of features, such as multiple data centers, high availability, and advanced networking options that are beneficial for Kubernetes clusters.


In this blog, we will be discussing the process of "Terraforming" a Kubernetes cluster on Linode using Terraform.

Getting Started with Terraform: Installing and Configuring


Before we can start using Terraform to provision and manage our Kubernetes cluster on Linode, we first need to install and configure it. Installing Terraform is a relatively straightforward process, and it can be done on a variety of different operating systems.


The first step in installing Terraform is to download the appropriate binary for your operating system from the Terraform website. Once you have the binary, you can install it by placing it in a directory that is included in your system's PATH. This will allow you to run the terraform command from any location on your system.


To download the appropriate binary for your operating system, use the following command:


wget 

https://releases.hashicorp.com/terraform/<version>/terraform_<version>_<os>_<arch>.zip

To install Terraform, use the following command:

unzip terraform_<version>_<os>_<arch>.zip -d /usr/local/bin/


Once Terraform is installed, you will need to configure it to use the Linode provider. The Linode provider is a plugin that allows Terraform to interact with the Linode API. This can be done by creating a provider block in your Terraform configuration file and specifying the Linode provider. You will also need to provide your Linode API key in the provider block, which can be obtained from the Linode Manager.


After configuring the Linode provider, you will also need to set up the credentials for Terraform to access the Linode API. This can be done by creating a provider block in your Terraform configuration file. You will also need to provide your Linode API key in the provider block, which can be obtained from the Linode Manager.


With Terraform installed and configured, you are now ready to start provisioning and managing your Kubernetes cluster on Linode. Now let's unravel how to set up Linode API keys for Terraform.

Setting up Linode API Keys for Terraform

This step involves setting up the necessary authentication for Terraform to interact with the Linode API. This is a crucial step in the process of Terraforming a Kubernetes cluster on Linode, as it allows Terraform to provision and manage resources on the Linode infrastructure.


To set up Linode API keys, you will first need to log into your Linode account and navigate to the "My Profile" section. From there, you can generate a new API key, which will be used by Terraform to authenticate with the Linode API. You will want to make sure to keep this key secure and not share it with anyone.


Once you have generated your API key, you will need to configure Terraform to use it. This can be done by adding it to the provider block in your Terraform configuration file. You will also need to specify the endpoint for the Linode API that you wish to use, as well as any other required information.


Once the Linode API keys are set up, Terraform will be able to authenticate and interact with the Linode API. This will allow you to provision and manage resources on the Linode infrastructure, such as virtual machines and networks, using Terraform. With the Linode API keys set up, the next step will be to create an instance with Terraform, introducing variables and output.

Building a Virtual Machine with Terraform: Variables and Outputs

Once Terraform is installed and configured and Linode API keys are set up, the next step is to build a virtual machine (VM) using Terraform. In this section, we will cover how to create a VM using Terraform, including how to use variables and outputs to make the process more flexible and manageable.


To create a VM using Terraform, you will need to create a resource block in your Terraform configuration file. The resource block should specify the type of resource being created (in this case, a Linode instance), and include any necessary arguments, such as the instance type, image, and region.


For example, the following block of code creates a Linode instance with the specified instance type, image, and region:


resource "linode_instance" "example" {
    type = var.instance_type
    image = var.image
    region = var.region
}


Notice that the block is using variables ( var.instance_type, var.image, var.region) to declare the type, image, and region of the instance. This allows for more flexibility and ease of management, as the values for these variables can be easily changed in a single location rather than having to make changes throughout the entire configuration file.


In addition to variables, you can also use outputs in Terraform to make the process of managing resources more manageable. Outputs allow you to extract information about the resources that have been created and use them in other parts of the Terraform configuration. For example, you can use an output to extract the IP address of the Linode instance that was created and use it to configure a firewall rule.


output "ip_address" {
  value = linode_instance.example.ip_address
}


The above code block will create an output named "ip_address" and the value will be the IP address of the linode_instance.example. This output can be later used to configure firewall rules or other resources.

Terraform Planning and Applying to Linode

Once you have created a Terraform configuration file that defines the resources you want to create and manage, the next step is to use Terraform to provision those resources on the Linode infrastructure. This is done by using the "terraform plan" and "terraform apply" commands.


The "terraform plan" command is used to generate an execution plan that shows the changes that Terraform will make to the resources on the Linode infrastructure. This command should be run before applying the changes to ensure that the changes are correct and to avoid any unexpected results.


For example, the following command will generate an execution plan for the Terraform configuration file in the current directory:


terraform plan


The "terraform apply" command is used to apply the changes defined in the execution plan to the Linode infrastructure. This command will create or modify the resources as specified in the Terraform configuration file.


For example, the following command will apply the changes to the Terraform configuration file in the current directory:


terraform apply


It will prompt for confirmation before applying the changes.


It's important to note that the "terraform plan" command should be run before the "terraform apply" command to ensure that the changes are correct and to avoid any unexpected results. Additionally, you should always keep a backup of your Terraform configuration files and state files so that you can easily roll back to a previous version of your infrastructure in case of any issues.


In summary, the "Terraform Planning and Applying to Linode" section covers the process of using the terraform plan and "apply command" to provision the resources defined in the Terraform configuration file on Linode infrastructure. The terraform plan command is used to generate an execution plan to check if the changes are correct before applying them to the Linode infrastructure. The terraform apply command is used to apply the changes on the Linode infrastructure.

Understanding the Terraform Console and its Use in Linode Kubernetes Engine


The Terraform console is a command-line tool that allows you to interact with Terraform's state file, which contains information about the resources that Terraform is managing. With the console, you can view and modify the resources that Terraform is managing and also see the plan that Terraform is going to apply before it actually makes the changes.


Here is an example of how to use the Terraform console:


# initialize the Terraform working directory
 terraform init 
# view the plan that Terraform will execute
 terraform plan 
# apply the plan and create the resources
 terraform apply 
# open the Terraform console
 terraform console


Once you are in the console, you can interact with the resources that Terraform is managing by using Terraform's built-in interpolation syntax. For example, you can use the resource function to access information about a specific resource, such as its ID or its current state.


# access the linode_instance resource
resource("linode_instance", "example")

# access the ID of the linode_instance
resource("linode_instance", "example").id

# access the current state of the linode_instance
resource("linode_instance", "example").state


Thus, using Terraform console, you can interact with Linode's Kubernetes Engine, which is a managed Kubernetes service provided by Linode. This section may also explain how to use the Terraform console to manage and provision Kubernetes clusters on Linode's infrastructure.

Creating a Kubernetes Configuration File with Terraform

Now let's see how to use Terraform's Kubernetes provider to create resources such as pods, services, and deployments in a Kubernetes cluster.


Here is an example of how to create a Kubernetes configuration file with Terraform:


provider "kubernetes" {
  config_path = "${path.module}/kubeconfig.yml"
}

resource "kubernetes_pod" "example" {
  metadata {
    name = "example-pod"
  }
  spec {
    container {
      image = "nginx:latest"
      name  = "example"
    }
  }
}

resource "kubernetes_service" "example" {
  metadata {
    name = "example-service"
  }
  spec {
    selector = {
      app = "${kubernetes_pod.example.metadata.0.name}"
    }
    port {
      port        = 80
      target_port = 80
    }
  }
}


This code block above creates a pod and a service in the Kubernetes cluster. The pod runs an Nginx container, and the service exposes the Nginx container on port 80.


The blog may also explain how to use Terraform's interpolation syntax to reference resources and variables in the configuration file and how to use Terraform modules to organize and reuse code.

Once the configuration file is ready, you can use terraform commands like terraform init, terraform plan and terraform apply to create the cluster on the Linode infrastructure.


It's important to note that for the above code to work, it is assumed that the kubeconfig.yml file is present in the same directory as the terraform configuration file, which contains the authentication details for the Kubernetes cluster.

Installing and Configuring Kubectl for Linode

Now let's see how to install and configure kubectl, which is a command-line tool for interacting with Kubernetes clusters, on a Linode server.


Here is an example of how to install kubectl on a Linux-based Linode server:


# download the kubectl binary
curl -LO "https://storage.googleapis.com/kubernetes-release/release/$(curl -L -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl"

# make the binary executable
chmod +x kubectl

# move the binary to a directory in the system PATH
sudo mv kubectl /usr/local/bin/


Once kubectl is installed, we can configure it to connect to the Kubernetes cluster on Linode by providing it with the cluster's kubeconfig file which should have the authentication details of the cluster.


# set the kubeconfig file for kubectl
export KUBECONFIG=path/to/kubeconfig.yml


We can also verify the kubectl installation and configuration by running commands such as kubectl version to check the version of kubectl, and kubectl get nodes to check the nodes in the cluster.


It's worth noting that kubectl installation is platform-specific; the above instructions are for a Linux-based Linode server; if you are using other platforms, please follow the instructions accordingly.

Setting up Visual Studio Code for Kubernetes Configuration Files

Now let's see how to set up Visual Studio Code, a popular code editor, for editing and working with Kubernetes configuration files.


This section probably covers how to install and configure Visual Studio Code extensions that provide syntax highlighting, code completion, and other features for working with Kubernetes configuration files.


Here is an example of how to install the Kubernetes extension for Visual Studio Code:


# Open the Extensions pane in Visual Studio Code
# (Ctrl + Shift + X)

# Search for "Kubernetes"

# Click the "Install" button for the Kubernetes extension


Once the extension is installed, it will provide features such as syntax highlighting, linting, and code snippets for Kubernetes configuration files written in YAML and JSON.


Additionally, this section may also explain how to set up the Kubernetes extension in Visual Studio Code to connect to a cluster and perform actions like creating, updating, or deleting resources.


# Open the Command Palette (Ctrl+Shift+P)
# type kubernetes
# select "Kubernetes: Connect to cluster"
# Follow the prompts to connect to your cluster


The Kubernetes extension's features simplify the process of editing and working with Kubernetes configuration files.


It's worth noting that the above instructions are for Visual Studio Code on Windows, Mac, or Linux; if you are using other platforms or other code editors, the instructions may vary.

Deploying a Public Container Image on Linode Kubernetes Engine


Now let’s see how to deploy a container image that is available publicly on a container registry, such as Docker Hub, to a Kubernetes cluster on Linode's infrastructure.

This section probably covers how to use kubectl, a command-line tool for interacting with Kubernetes clusters, to create and manage resources such as pods, services, and deployments in the cluster.


Here is an example of how to deploy a public container image to a Kubernetes cluster:


# create a deployment
kubectl create deployment my-nginx --image=nginx:latest
# expose the deployment as a service
kubectl expose deployment my-nginx --port=80 --type=LoadBalancer


This code block creates a deployment named "my-nginx" that runs the latest version of the Nginx container image and exposes the deployment as a service on port 80 with a load balancer.


One can also comprehend how to check the status of the deployment, scale the deployment, and perform other actions on the resources in the cluster.


# check the status of the deployment
kubectl get pods
# scale the deployment to run 3 replicas
kubectl scale deployment my-nginx --replicas=3
# update the deployment to use a new container image
kubectl set image deployment my-nginx my-nginx=nginx:1.19


It's worth noting that the above instructions are for deploying a public container image from a container registry, such as Docker Hub; if you want to deploy a container image that you've built yourself, you will need to push it to a container registry before deploying it to the cluster.

Setting up Ingress for Container Images on Linode

Now let’s understand the process of configuring Ingress, a Kubernetes resource that allows external traffic to reach the pods in a cluster on a Linode cluster that is managed using Terraform.


This can be done by following the steps below:


1.       Creating an Ingress resource in a Terraform configuration file, which specifies the rules for routing incoming traffic to the appropriate pods in the cluster. An example of this might look like this:


resource "kubernetes_ingress" "example" {
  metadata {
    name = "example-ingress"
    annotations = {
      "nginx.ingress.kubernetes.io/rewrite-target" = "/"
    }
  }
  spec {
    rule {
      host = "example.com"
      path {
        path = "/example-path"
        path_type = "Prefix"
      }
      http {
        path {
          path = "/example-path"
          path_type = "Prefix"
          backend {
            service {
              name = "example-service"
              port = {
                name = "http"
                port = 80
              }
            }
          }
        }
      }
    }
  }
}


  1. Creating a Service resource in Terraform, which defines how traffic is routed to the pods in the cluster. This looks like the following:


    resource "kubernetes_service" "example" {
      metadata {
        name = "example-service"
      }
      spec {
        selector = {
          app = "example"
        }
        port {
          name = "http"
          port = 80
        }
      }
    }
    

3. Applying the Terraform configuration to create the Ingress and Service resources on the Linode cluster using the terraform apply command.


  1. Configuring DNS records to point to the Linode cluster so that traffic to the specified hostname is directed to the Ingress resource.


  2. Verifying that incoming traffic is being routed to the appropriate pods in the cluster by checking the logs for the Ingress controller, and testing the application by accessing it via the hostname.

Using Terraform to Map a Custom Domain to your Kubernetes Cluster on Linode


Now let’s try to explain the process of using Terraform to create a DNS record that maps a custom domain to the Kubernetes cluster running on Linode. This allows external traffic to reach the cluster by accessing it via the custom domain rather than the IP address of the Linode instance. This can be achieved by orchestrating the steps:


  1. Creating a Linode DNS zone resource in Terraform, which defines the DNS zone for the custom domain. An example of this might look like this:


resource "linode_dns_zone" "example" {
  domain = "example.com"
  soa_email = "[email protected]"
}


  1. Creating a Linode DNS record resource in Terraform, which defines the A record for the custom domain. This would map the domain to the IP address of the Linode instance running the Kubernetes cluster. An example of this looks like the following:


resource "linode_dns_record" "example" {
  domain = linode_dns_zone.example.domain
  name = "@"
  type = "A"
  target = "1.2.3.4"
  priority = 10
  ttl_sec = 300
}


Applying the Terraform configuration to create the DNS zone and record resources on the Linode account using the terraform apply command.


Configuring the Kubernetes cluster to use the custom domain by updating the Ingress resource and service with the new domain name.


Verifying that the custom domain is properly mapped to the Linode instance by using the nslookup or dig command to look up the A record for the domain and testing the application by accessing it via the custom domain.


nslookup example.com


6. Updating the DNS records periodically to ensure that the custom domain is always pointing to the correct IP address of the Linode instance running the Kubernetes cluster.


Wrap Up

Using Terraform and Kubernetes on Linode has several key benefits and is significant because of the following reasons:


First, Terraform allows for infrastructure-as-a-code, which means that the entire infrastructure can be defined and managed using code rather than manual configuration. This makes it easier to automate the provisioning and management of resources and to version control and track changes to the infrastructure.


Second, Kubernetes is a powerful and widely-used container orchestration system that allows for the scaling and management of containerized applications. By using Kubernetes on Linode, users can easily deploy and manage their applications and scale them as needed to meet changing demands.


Third, Linode is a cloud hosting provider that offers a variety of compute, storage, and networking options. By using Terraform and Kubernetes on Linode, users can take advantage of Linode's resources while also leveraging the automation and management capabilities of Terraform and Kubernetes.


Fourth, by combining all three technologies together, users can take advantage of the powerful infrastructure management capabilities of Terraform and the container orchestration capabilities of Kubernetes, all while leveraging the resources provided by Linode. This allows for a more efficient, scalable, and cost-effective infrastructure management solution that can easily adapt to changing business needs.


Overall, orchestrating Terraform and Kubernetes on Linode is a powerful combination that can help organizations efficiently manage and scale their infrastructure, ultimately setting themselves up for long-term success.


I hope this blog proves to be a valuable resource for anyone looking to use Terraform and Kubernetes on Linode. It provides a comprehensive overview of using Terraform to manage Kubernetes clusters on Linode, covering key concepts such as creating and managing resources, using modules, and troubleshooting common issues. By following the steps outlined in this guide, users can confidently deploy and manage their own Kubernetes clusters on Linode, ensuring their application is always running smoothly.


The significance of this guide is that it not only teaches readers how to set up Kubernetes on Linode but also how to use Terraform, which is an industry-standard tool for infrastructure-as-a-code (IaC) and its automation. This is especially important in today's fast-paced and constantly evolving technology landscape, where automation and scalability are essential for any successful business. By reading this blog, readers will gain the knowledge and skills needed to effectively manage and scale their infrastructure, setting themselves up for long-term success.