Deployments

Question 1

Is POD gets restarts by itself, if it goes down ?

Answer 1

No, some other mechanism is required to replace the POD.

Question 2

What is the main role of Deployment object in kubernetes?

Answer 2

Manage replica sets thereby managing pod

Question 3

What is a replica set ?

Answer 3

It is used to manage the PODs.

Question 4

What is a deployment ?

Answer 4

It is used to manage the “replica sets”.
The “replica set” came before “deployments”. The main objective behind “deployments” is to simplify the process of managing replica sets.

Question 5

What are the main objectives of Replica Sets ?

Answer 5

1. POD management - No need to create the pods separately, it creates them
2. Auto-scaling: Increase the number of PODs if required by the user
3. Self healing: Keep the number of PODs as mentioned by the user

Question 6

What are the main objectives of Deployments?

Answer 6

1. Replica set management - No need to create the replica set, it creates them
2. Auto-scaling: It scales replica sets, which scales PODs
3. Self-healing: It increases the number of PODs, by scaling the replica sets
4. Zero-downtime updates
5. Rollback functionality
6. Tagging mechanism using “labels”

Question 7

Do we need to create both Replica sets and Deployments ?

Answer 7

No.
Deployments are wrapper above replica sets. Hence once we create the Deployments, it automatically creates the Replica sets automatically.

Question 8

Do we need to provide “specs” for “replica sets” while creating the “Deployment” ?

Answer 8

No.
Only POD specs are required. Replica sets gets created automatically.

Question 9

Define Deployment manifest ?

Answer 9

apiVersion: v1
kind: Deployment
metadata:
spec:
selector:
template:
spec:
containers:
- name: my-nginx
image: nginx:alpine

Question 10

Where we provide the “labels” in manifest ?

Answer 10

Inside the “meta-data”
metadata:
name: frontend
labels:
key: value

Question 11

what are the two main objectives of using “labels” ?

Answer 11

1. To query a resource e.g. get Everything having label - “mylabel”
2. To Group objects together e.g. Deploy everything with label - “myLabel”

Question 12

What’s the command to create a deployment object?

Answer 12

> > > kubectl apply -f myFile.deployment.yaml

Question 13

How to get all the deployments running in kubectl ?

Answer 13

> > > kubectl get deployment

Question 14

How to show all the labels of the deployments ?

Answer 14

> > > kubectl get deployment –show-labels

Question 15

How to filter out the deployments based on “labels” ?

Answer 15

> > > kubectl get deployment -l app=nginx –show-labels

Question 16

How to delete a deployment ?

Answer 16

> > > kubectl delete deployment [deployment-name]

Question 17

Can we scale deployment?

Answer 17

No, only replica can be scaled.

Question 18

How to provide scaling configuration in YAML file ?

Answer 18

Inside the Deployment “Spec”:
spec:
replicas: 3
selector:

Question 19

How to provide the scaling configuration from command line ?

Answer 19

> > > kubectl scale -f myFile.deployment.yaml –replicas=5

Question 20

How to bound the Template with the selector ?

Answer 20

By Matching the label of “template” with “matchlabel”.

Question 21

How to provide labels to the “template” within Deployment manifest ?

Answer 21

template:
metadata:
labels:
key1: value1

Question 22

How to update already deployed deployment ?

Answer 22

> > > kubectl apply -f myFile.yml
This will update the existing configuration

Question 23

What is the meaning of ZERO downtime update using Deployment ?

Answer 23

It means, Deployments allows us to update our containers without any downtime.

Question 24

What are the different Deployment Options provided by the Kubernetes ?

Answer 24

1. Rolling Update
2. Blue-Green Deployment
3. Canary Deployment
4. Rollback Deployment

Question 25

What is the default deployment option given by Kuberentes ?

Answer 25

Rolling update

Question 26

How Rolling update deployment works in K8s?

Answer 26

1. A new container will be deployed with new version
2. Once its ready to receive request (monitored by readiness probe), one of old version gets terminated
3. This sequence continues to get run, until all older version gets removed

Question 27

How to run “rolling update” deployment ?

Answer 27

It is default option.
»>
kubectl apply -f my-nginx.deployment.yaml