Certified Kubernetes Application Developer (CKAD) Study Guide

Answers to Review Questions

Chapter 2, Core Concepts

1. You can either use the imperative approach or the declarative approach. First, we’ll look at creating the namespace with the imperative approach:

   $ kubectl create namespace ckad
   

   Create the Pod:

   $ kubectl run nginx --image=nginx:1.17.10 --port=80 --namespace=ckad
   

   Alternatively, you can use the declarative approach. Create a new YAML file called ckad-namespace.yaml with the following contents:

   apiVersion: v1
   kind: Namespace
   metadata:
     name: ckad

   Create the namespace from the YAML file:

   $ kubectl create -f ckad-namespace.yaml
   

   Create a new YAML file called nginx-pod.yaml with the following contents:

   apiVersion: v1
   kind: Pod
   metadata:
     name: nginx
   spec:
     containers:
     - name: nginx
       image: nginx:1.17.10
       ports:
       - containerPort: 80

   Create the Pod from the YAML file:

   $ kubectl create -f nginx-pod.yaml --namespace=ckad
   

2. You can use the command-line option -o wide to retrieve the IP address of the Pod:

   $ kubectl get pod nginx --namespace=ckad -o wide
   

   The same information is available if you query for the Pod details:

   $ kubectl describe pod nginx --namespace=ckad | grep IP:
   

3. You can use the command-line options --rm and -it to start a temporary Pod. The following command assumes that the IP address of the Pod named nginx is 10.1.0.66:

   $ kubectl run busybox --image=busybox --restart=Never --rm -it -n ckad \
     -- wget -O- 10.1.0.66:80
   

4. To download the logs, use a simple logs command:

   $ kubectl logs nginx --namespace=ckad ...