1 - Core Concepts

Question 1

Create a namespace called ‘mynamespace’ and a pod with image nginx called nginx on this namespace

Answer 1

kubectl create namespace mynamespace
kubectl run nginx –image=nginx –restart=Never -n mynamespace

Question 2

Create the pod that was just described using YAML

Answer 2

kubectl run nginx –image=nginx –restart=Never –dry-run=client -n mynamespace -o yaml > pod.yaml

Question 3

Create a busybox pod (using kubectl command) that runs the command “env”. Run it and see the output

Answer 3

kubectl run busybox –image=busybox –command –restart=Never -it –rm – env

Question 4

Create a busybox pod (using YAML) that runs the command “env”. Run it and see the output

Answer 4

kubectl run busybox –image=busybox –restart=Never –dry-run=client -o yaml –command – env > envpod.yaml

Question 5

Get the YAML for a new namespace called ‘myns’ without creating it

Answer 5

kubectl create namespace myns -o yaml –dry-run=client

Question 6

Create the YAML for a new ResourceQuota called ‘myrq’ with hard limits of 1 CPU, 1G memory and 2 pods without creating it

Answer 6

kubectl create quota myrq –hard=cpu=1,memory=1G,pods=2 –dry-run=client -o yaml

Question 7

Get pods on all namespaces

Answer 7

kubectl get po –all-namespaces

Question 8

Create a pod with image nginx called nginx and expose traffic on port 80

Answer 8

kubectl run nginx –image=nginx –restart=Never –port=80

Question 9

Change pod’s image to nginx:1.7.1. Observe that the container will be restarted as soon as the image gets pulled

Answer 9

kubectl set image pod/nginx nginx=nginx:1.7.1
kubectl describe po nginx # you will see an event ‘Container will be killed and recreated’
kubectl get po nginx -w # watch it

Question 10

Get nginx pod’s ip created in previous step, use a temp busybox image to wget its ‘/’

Answer 10

kubectl run busybox –image=busybox –rm -it –restart=Never – wget -O- $(kubectl get pod nginx -o jsonpath=’{.status.podIP}:{.spec.containers[0].ports[0].containerPort}’)

Question 11

Get pod’s YAML

Answer 11

kubectl get po nginx -o yaml

Question 12

Get information about the pod, including details about potential issues (e.g. pod hasn’t started)

Answer 12

kubectl describe po nginx

Question 13

Get pod logs

Answer 13

kubectl logs nginx

Question 14

If pod crashed and restarted, get logs about the previous instance

Answer 14

kubectl logs nginx -p
# or
kubectl logs nginx –previous

Question 15

Execute a simple shell on the nginx pod

Answer 15

kubectl exec -it nginx – /bin/sh

Question 16

Create a busybox pod that echoes ‘hello world’ and then exits

Answer 16

kubectl run busybox –image=busybox -it –restart=Never – /bin/sh -c ‘echo hello world’

Question 17

Do the same, but have the pod deleted automatically when it’s completed

Answer 17

kubectl run busybox –image=busybox -it –rm –restart=Never – /bin/sh -c ‘echo hello world’

Question 18

Create an nginx pod and set an env value as ‘var1=val1’. Check the env value existence within the pod

Answer 18

kubectl run nginx –image nginx –restart=Never –env=var1=val1 -it –rm – sh -c ‘echo $var1’