Application Lifecycle Management

Question 1

What is the command to see the rollout status?

Answer 1

k rollout status deployment/<deployment_name></deployment_name>

Question 2

What is the command to see the revisions of the deployment

Answer 2

k rollout history deployment/<deployment_name></deployment_name>

Question 3

What is the major disadvantage of the Recreate deployment strategy?

Answer 3

The application will be down for some amount of time

Question 4

What does the Rolling Update Deployment Strategy do?

Answer 4

The new version is deployed in between taking down a previous version, ensuring the application is always up

Question 5

What command updates a deployment after the manifest has been modified?

Answer 5

k apply -f <deployment_manifest>.yaml</deployment_manifest>

Question 6

What is the imperative command to update the image for a deployment?

Answer 6

k set image deployment/<deployment_name> \ nginx=nginx:1.9.1</deployment_name>

Question 7

What is the command to rollback a deployment?

Answer 7

k rollout undo deployment/<deployment_name></deployment_name>

Question 8

How do define a command argument to an image in a manifest?

Answer 8

Add the args parameter under spec. eg.

spec:
containers:
- name: ubuntu-sleeper
image: ubuntu-sleeper
args: [“10”]

Question 9

How do define a docker style entrypoint in a manifest?

Answer 9

Add the command parameter under spec. eg.

spec:
containers:
- name: ubuntu-sleeper
image: ubuntu-sleeper
command: [“sleep2.0”]
args: [“10”]

Question 10

How do you set arguments when running a pod from an imperative command?

Answer 10

k run <name> --image=<image_name> -- <arg1> <arg2></arg2></arg1></image_name></name>

Question 11

How do you set environment variables in a manifest?

Answer 11

Use the env parameter under the spec section. Environment variables should be in an array. eg.

spec:
containers:
…
env:
- name:
value:

Question 12

What is the purpose of a config map?

Answer 12

Config maps are used to pass configuration data in the form of key value pairs in Kubernetes.

Question 13

What is the imperative command to create a configmap?

Answer 13

k create configmap \
app-config – from-literal=APP_COLOR=blue

Question 14

What is the imperative command to create a configmap from a file?

Answer 14

k create configmap \
<config-name> --from-file=<path-to-file></path-to-file></config-name>

Question 15

How do you create a declarative configmap?

Answer 15

apiVersion: v1
kind: ConfigMap
metadata:
name: app-config
data:
APP_COLOR: blue
APP_MODE: prod

Question 16

What is the command to list configmaps?

Answer 16

k get configmaps

Question 17

What is the command to describe a configmap?

Answer 17

k describe configmaps

Question 18

How do you specify a configmap in a manifest?

Answer 18

Under the spec section in container definition, add an envFrom. eg.

spec:

Question 19

What is the command to replace an existing pod from a file (generally done when editing is not allowed)?

Answer 19

k replace –force -f <filename>.yaml</filename>

Question 20

How do you imperatively create a secret?

Answer 20

k create secret <secret_name> \
app-secret --from-literal=DB_Host=mysql</secret_name>

Question 21

How do you imperatively create a secret and specify a file to read from?

Answer 21

k create secret <secret_name> \
app-secret --from-file=<name>.properties</name></secret_name>

Question 22

What kind value denotes a secret?

Answer 22

Secret

Question 23

What is the command to encode secrets in base64?

Answer 23

echo -n ‘<value>' | base64</value>

Question 24

What is the command to decode secrets in base64?

Answer 24

echo -n ‘<value>' | base64 --decode</value>

Question 25

How do specify a pod to use a secret in a manifest as an env variable?

Answer 25

spec:
containers:
…
:
- secretRef:
name: app-secret

Question 26

How do specify a pod to use a secret in a manifest as a single env variable?

Answer 26

spec:
containers:
…
env:
- name: DB_Password
valueFrom:
secretKeyRef:
name: app-secret
key: DB_Password

Question 27

How do you inject a secret as a file in a volume?

Answer 27

volumes:
- name: <app-secret-volume>
secret:
secretName: <app-secret></app-secret></app-secret-volume>

Question 28

What happens when you use a secret with multiple variables in a volume?

Answer 28

A file for each secret will be injected into the volume

Question 29

Are secrets encrypted?

Answer 29

No, they are only encoded

Question 30

Are secrets encrypted in ETCD?

Answer 30

No, but you can encrypt at rest

Question 31

Why is a container spec an array?

Answer 31

An array gives you the ability to add multiple containers to a manifest