Kubernates

link for kubernate installation help https://www.cloudsigma.com/how-to-install-and-use-kubernetes-on-ubuntu-20-04/

Namespaces in kubernates

List the current namespaces in a cluster using:

Create a new YAML file called my-namespace.yaml

Edit using nano editor with the contents:

Run using following command

Can view new created namespace using following command

Another way of creating namespace is as follows:

Delete a namespace with following command

Pods in Kubernates

They can be simply created with the kubctl run command, where you have a defined image on the Docker registry which we will pull while creating a pod.

This can also be done by creating the yaml file and then running the kubectl create command.

Multi container pods are created using yaml file with the definition of the containers.

Implementation of storage class and pvc

Create a storage class using vi editor

Create a storage class using following command:

Let’s create a PVC yaml using the above storage class…

We can create this resource and check for the following outputs:

show list of all pvc

Daemonset

describe a DaemonSet in a YAML file. For example, the daemonset.yaml file below describes a DaemonSet that runs the fluentd-elasticsearch Docker image:

create a Daemonset using following command:

Implementation of Configmap and secret application (with DB)

In configmap example, we will create a simple YAML that contains the data using vi editor

Configmap created using the kubectl apply command as shown below.

Use the following command with the appropriate ConfigMap name defined in the metadata section.

As secrets are defined by type, let’s create a basic-auth type Secret that contains the database username and password using vi editor

Secret can be created using the kubectl apply command as shown below.

As secrets contain confidential data, the describe command does not expose this secret data even when the user query through the kubectl using the specific secret name.

HelmChart

use the helmcreate command to create a helmchart

Let’s deploy an Apache webserver using Helm. As a first step, we need to tell Helm what location to search by adding a Helm repository:

Let’s install the actual container:

After a few minutes your deployment is ready. We can check the state of the containers using kubectl:

Helm can show us information about current deployments:

Helm stores deployment information in secrets – here they are:

Deply wordpress using helm chart
We can install using command as follows:

GitLab

Installation of GitLab in ubuntu using following command: