40 Days Of Kubernetes (6/40)

GitHub link - https://github.com/SUBHAM-NANDI/40DaysKubernetes/tree/main/Day%206

Step 1: Install kind

kind is a tool that lets you run Kubernetes clusters locally using Docker containers as cluster nodes. To install kind, you can use Homebrew (for macOS):

brew install kind

To verify that kind is installed successfully, run:

kind version

This should display the version of kind installed.

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Step 2: Create a Cluster with kind

Once kind is installed, you can create a Kubernetes cluster. By default, kind creates a single-node cluster, but you can configure a multi-node cluster. To create a simple single-node cluster:

kind create cluster --name eka-cluster1

For a multi-node cluster, you'll need to provide a configuration file. First, create a YAML configuration file (config.yml), which defines the cluster's setup.

Example for a multi-node configuration:

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
  - role: control-plane  # This will act as the master node
  - role: worker         # Worker node 1
  - role: worker         # Worker node 2

After saving the above configuration to config.yml, create the cluster:

kind create cluster --name eka-cluster1 --config config.yml

This command will create a cluster named eka-cluster1 with one control-plane node and two worker nodes.

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Step 3: Install kubectl

kubectl is the command-line tool used to interact with Kubernetes clusters. To install kubectl, run the following command:

curl -LO "https://dl.k8s.io/release/$(curl -L -s https://dl.k8s.io/release/stable.txt)/bin/darwin/amd64/kubectl"

Ensure that your kubectl version is compatible with the Kubernetes version used by kind.

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Step 4: Verify the Cluster is Running

Once the cluster is created, you can verify that all the nodes (control-plane and worker nodes) are up and running using kubectl:

kubectl get nodes

This should show you a list of all the nodes in the cluster, along with their statuses.

Here, we can see that the control-plane and worker nodes are running.

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Step 5: Create a Multi-Node Configuration File

If you haven’t already, create a custom kind configuration file to define your multi-node cluster. This allows you to explicitly control how many nodes (control-plane and workers) are created.

Here’s an example config.yml:

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
nodes:
  - role: control-plane  # This node will run the Kubernetes master components
  - role: worker         # Worker node 1
  - role: worker         # Worker node 2
  - role: worker         # Worker node 3 (optional)
networking:
  disableDefaultCNI: false

You can adjust the number of worker nodes as needed. The disableDefaultCNI: false ensures that kind uses its default CNI (Container Network Interface).

Now, create the cluster with the new configuration:

kind create cluster --name eka-cluster --config config.yml

This will set up a control-plane (master) node and multiple worker nodes.

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Step 6: Inspect the Cluster Context

Kubernetes supports multiple clusters, and kubectl uses contexts to manage these clusters. To view the contexts (active clusters) on your system, run:

kubectl config get-contexts

This will list all the available contexts and indicate which one is currently active.

For example:

CURRENT   NAME                CLUSTER             AUTHINFO            NAMESPACE
*         kind-eka-cluster    kind-eka-cluster    kind-eka-cluster

The * indicates the current active context, meaning you are working in the kind-eka-cluster.

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*Step 7: Switch Contexts *

If you're working with multiple clusters, you may need to switch between contexts. To change the active context to your kind cluster, run:

kubectl config use-context kind-eka-cluster

This sets the eka-cluster as the current active cluster.

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Step 8: Deploy Applications or Test the Cluster

Now that your Kubernetes multi-node cluster is up and running, you can start deploying applications, services, or running tests.

For example, to deploy a sample Nginx application on your cluster, run:

kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort

This will create a deployment with Nginx and expose it on a NodePort so you can access it from outside the cluster.

To verify the deployment is running:

kubectl get pods

And to get the URL to access the Nginx service:

kubectl get services

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Step 9: Cleanup (Optional)

Once you are done with the cluster, you can delete it to free up resources:

kind delete cluster --name eka-cluster

This will delete the cluster, removing all the resources and nodes associated with it.