Infosec Consultant & Pentester

57/100 Print Environment Variables

Chris Young -

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.

  1. Create a pod named print-envars-greeting.
  2. Configure spec as, the container name should be print-env-container and use bash image.
  3. Create three environment variables:

a. GREETING and its value should be Welcome to

b. COMPANY and its value should be DevOps

c. GROUP and its value should be Industries

  1. Use command ["/bin/sh", "-c", 'echo "$(GREETING) $(COMPANY) $(GROUP)"'] (please use this exact command), also set its restartPolicy policy to Never to avoid crash loop back.
  2. You can check the output using kubectl logs -f print-envars-greeting command.

First, create the yaml file for our pod which will be named print-envars-greeting.yaml

apiVersion: v1
kind: Pod
metadata:
  name: print-envars-greeting
spec:
  containers:
    - name: print-env-container
      image: bash
      command: ["/bin/sh", "-c", 'echo "$(GREETING) $(COMPANY) $(GROUP)"']
      env:
        - name: GREETING
          value: "Welcome to"
        - name: COMPANY
          value: "DevOps"
        - name: GROUP
          value: "Industries"
  restartPolicy: Never

Apply the yaml file and then check the status of the pod:

thor@jumphost ~$ kubectl apply -f print-envars-greeting.yaml
pod/print-envars-greeting created

thor@jumphost ~$ kubectl get pods
NAME                    READY   STATUS      RESTARTS   AGE
print-envars-greeting   0/1     Completed   0          76

Finally, view the log output:

thor@jumphost ~$ kubectl logs -f print-envars-greeting
Welcome to DevOps Industries

Explanation

restartPolicy: Never  - This ensures the Pod won’t restart once it completes the echo command.

The bash image runs the command and prints the concatenated environment variables.

The echo "$(GREETING) $(COMPANY) $(GROUP)" syntax uses shell substitution to combine them.