Kubernetes Architecture

Question 1

Assuming you have a Dockerfile in the directory you are working in, what is the command to build a container image named ‘myapp’ with a tag of ‘v1.0’?

Answer 1

docker build -t myapp:v1.0 .

Question 2

What is the command to run a docker container in the background (detached)? The container should be called mycontainer and the image is named myapp. Any traffic sent to port 2224 should be forwarded to port 8888 inside the container.

Answer 2

sudo docker run -p 2224:8888 —name mycontainer -d myapp

Question 3

What is the command to check out what contexts are available?

Answer 3

kubectl config get-contexts

Question 4

Switch to a context called dev.

Answer 4

kubectl config use-context dev

Question 5

Use a command to see all the resources you can create.

Answer 5

kubectl api-resources

Question 6

Issue the command to see all the namespaces within a cluster

Answer 6

kubectl get namespaces

OR

kubectl get ns

Question 7

Describe the default namespace.

Answer 7

kubectl describe ns default

OR

kubectl describe namespace default

Question 8

Type out a manifest to create a namespace called test.

Answer 8

—-
apiVersion: v1
kind: Namespace
metadata:
name: test

Question 9

Create a new namespace from a file called ns-test.yaml.

Answer 9

kubectl create -f ns-test.yaml

Question 10

Create a namspace called dev from the CLI.

Answer 10

kubectl create ns dev

Question 11

Write a resource quota manifest. Give it a name of tiny-rq. Give it 1 cpu and 1Gi of memory.

Answer 11

—-
apiVersion: v1
kind: ResourceQuota
metadata:
name: tiny-rq
spec:
hard:
cpu: “1”
memory: 1Gi

Question 12

Create a resource quota from a manifest called rq-tiny.yaml in the test namespace

Answer 12

kubectl apply -f rq-tiny.yaml -n test

Question 13

Delete a resource quota named rq-tiny from the test namespace

Answer 13

kubectl delete resourcequota rq-tiny -n test

Question 14

Show al the pods in the current namespace and sort them by restart count.

Answer 14

kubectl get pods —sort-by=’.status.containerStatuses[0].restartCount’

Question 15

Show all the services in the current namespace and sort them by name.

Answer 15

kubectl get services —sort-by=.metadata.name

Question 16

Show all the pods across all the namespces and show extra details.

Answer 16

kubectl get pods —all-namespaces -o wide

Question 17

Show everything except secrets across all namespaces.

Answer 17

kubectl get all -A

Question 18

Create a port-forward to a pod called nginx from port 2224 to port 80 in the pod.

Answer 18

kubectl port-forward nginx 2224:80

Question 19

Write a pod manifest using the following information:

Pod Name: simpleservece
Pod Label: simpleservice-web
Container Name: simpleservice-web
image: mhousenblas/simpleservice:0.5.0
Port Name: web
Container Port: 9876
protocol: TCP

Answer 19

—-
apiVersion: v1
kind: Pod
metadata:
name: simpleservice
labels:
name: simpleservice-web
spec:
containers:
- name: simpleservice-web
image: mhausenblas/simpleservice:0.5.0
ports:
- name: web
containerPort: 9876
protocol: TCP

Question 20

Port forward a pod called simpleservice from 2224 to 9876 in the pod allowing all ip addresses to access it.

Answer 20

kubectl port-forward simpleservice 2224:9876 —address=0.0.0.0

Question 21

Create a pod on the command line using the nginx image. Name the pod webserver.

Answer 21

kubectl run webserver —image=nginx

Question 22

Execute the date command on a pod called webserver.

Answer 22

kubectl exec webserver — date

Question 23

Open an interactive session inside a pod called nginx.

Answer 23

kubectl exec -it nginx — bash

Question 24

Copy a file from local to a pod named my_pod with one container in it.

Answer 24

kubectl cp <local> my_pod:<remote></remote></local>

Question 25

Copy a file from a pod named web_server with only one container in it to local.

Answer 25

kubectl cp web_server:<remote> <local></local></remote>

Question 26

Copy a file from local into a multi-container pod named web_server into a container called webby.

Answer 26

kubectl cp <local> web_server:<remote> -c webby</remote></local>

Question 27

A context is a reference to…

Answer 27

…a cluster, namespace, and user

Question 28

Write and httpGet liveness probe for a container. Make it wait 2 seconds before it starts and it should check every 5 seconds. The path is /health on port 9876. It should fail if it hasn’t succeeded in 1 second. Only let it fail three times.

Answer 28

livenessProbe:
initialDelaySeconds: 2
periodSeconds: 5
httpGet:
path: /health
port: 9876
timeoutSeconds: 1

failureThreshold: 3

Question 29

Write an exec command liveness probe for a container. Give it an initial delay of 2 seconds. Make it check every 5 seconds. Let the probe have 1 second to decide whether the probe has succeeded or failed. It should only be allowed to check three times. Make it succeed twice in a row before it is considered live.

Answer 29

livenessProbe:
initialDelaySeconds: 2
periodSeconds: 5
exec:
command:
- cat
- /tmp/healthy
timeoutSeconds: 1
failureThreshold: 3
successThreshold: 2

Question 30

What type of probe has a timeoutSeconds parameter?

Answer 30

The livenessProbe:

Question 31

Write a readiness probe for a container using the httpGet method. The path is /health and port is 8080. Make sure there is an initialDelay of 3 seconds. Make it check every 4 seconds. Make sure it has to succeeed twice to be considered ready.

Answer 31

readinessProbe:
httpGet:
path: /health
port: 8080
initialDelaySeconds: 4
periodSeconds: 4
successThreshold: 2

Question 32

A liveness prob is intended to assure that a container is…

Answer 32

still performing its essential tasks.

Question 33

What can you add to a container that you suspect may not be performing its tasks but still may be running?

Answer 33

Add a liveness probe! This will cause the container to reboot when the container is running but not performing it’s function.

Question 34

What parameter would you set in a liveness probe to make it check liveness every 5 seconds for all eternity?

Answer 34

Set the periodSeconds parameter to 5.

Question 35

Check the readiness of a pod called sise-lp on the command line by describing the pod and grepping for ‘health’.

Answer 35

kubectl describe pods sise-lp | grep -i health

Question 36

Check the readiness of a pod called sise-lp on the command line by sending a curl to localhost:2224/health.

Answer 36

Step 1: Port forward the pod.
kubectl port-forward sise-lp 2224:9876 —address=0.0.0.0

Step 2: Send the curl request
curl localhost:2224/health

Question 37

Write a readiness probe using the exec command method. Target /tmp/healthy. Give it 3 seconds delay before starting. Make it check every 4 seconds and make it succeed twice before being considered ready.

Answer 37

readinessProbe:
exec:
command:
- cat
- /tmp/healthy
initialDelaySeconds: 3
periodSeconds: 4
successThreshold: 2