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TASK 92: Print Environment Variables

Requirements​

The Nautilus DevOps team is working on to setup some pre-requisites for an application that will send the greetings to different users. There is a sample deployment, that needs to be tested. Below is a scenario which needs to be configured on Kubernetes cluster. Please find below more details about it.

  • Create a pod named print-envars-greeting.

  • Configure spec as, the container name should be print-env-container and use bash image.

  • Create three environment variables:

    a. GREETING and its value should be Welcome to

    b. COMPANY and its value should be Nautilus

    c. GROUP and its value should be Group

  • Use command to echo ["$(GREETING) $(COMPANY) $(GROUP)"] message.

You can check the output using kubctl logs -f [ pod-name ] command.

Note: The kubectl utility on jump_host has been configured to work with the kubernetes cluster.

Note

This document focuses on the implementation approach. The task statement in Requirements is preserved as the source requirement.

Prerequisites​

  • Access to the configured Kubernetes cluster from jump_host.
  • kubectl is configured and points to the correct context.
  • Use the task-specified namespace, resource names, and images exactly.

Steps​

Create print.yml based on the requirements.

apiVersion: v1
kind: Pod
metadata:
  name: print-envars-greeting
  labels:
    name: print-envars-greeting
spec:
  containers:
    - name: print-env-container
      image: bash
      env:
        - name: GREETING
          value: "Welcome to"
        - name: COMPANY
          value: "Nautilus"
        - name: GROUP
          value: "Industries"
      command: ["echo"]
      args: ["$(GREETING) $(COMPANY) $(GROUP)"]

Apply.

kubectl apply -f print.yml

Verify.

$ kubectl get pods

NAME                    READY   STATUS             RESTARTS   AGE
print-envars-greeting   0/1     CrashLoopBackOff   1          12s
$ kubectl logs print-envars-greeting

Welcome to Nautilus Industries

Note:

As we can see above, the Pod printed the values we need in its logs. However, the Pod still has a status of "CrashLoopBackOff". This is okay in this lab.

The reason for this is that because we only use the image “bash” and inside the “bash” image there is no parent process defined which keeps running the pod after creation.

The same thing goes for the “busybox” image. But if we want to see a different example, then we can choose the “nginx” image, where a parent process is defined inside the image and that it keeps running the pod after creation.

If we want the pod to be in a running condition for a time of period then you can assign:

command: [“sleep”, “10000”] in the pod.spec.containers!!

Read more about it here: Define a Command and Arguments for a Container

Verification​

  • Confirm the required pods/services/deployments/jobs are in the expected state.
  • Run kubectl get commands for the affected resource types and namespace.

Resources​