Please note that below rolling update exercise is only
applicable if you maintaining container image versioning for each deployment. That
means you cannot perform rolling update for two deployments with same version
number.
If you are looking for a way to do this while keeping the
same version number, please check this post J
First we need add rolling update strategy to the deployment
yaml.
Below is the required part to be added to the yaml file,
strategy:
type: RollingUpdate
rollingUpdate:
maxSurge: 1 # this is limit to
create extra pods while rolling update
maxUnavailable: 1 # this is the limit
that can unavailable during rolling update
minReadySeconds: 25 # this is the minimum time
to start your application
Below is a sample deployment yaml file with above strategy,
apiVersion: apps/v1
kind: Deployment
metadata:
name: test
labels:
app: test
spec:
replicas: 2
selector:
matchLabels:
app: test
strategy:
type: RollingUpdate
rollingUpdate:
maxSurge: 1
maxUnavailable: 1
minReadySeconds: 25
template:
metadata:
labels:
app: test
version: v1
spec:
imagePullSecrets:
- name:
containers:
- name: test
image: test:1.0.0 # different versioning number is a must to
perform rolling update
ports:
- name:
containerPort: 8080
Now apply the deployment with –record flag.
$ kubectl.exe apply -f <your
deployment name>.yml --record
Now you can run below
command to start rolling update. You must mention a different version number
here.
$ kubectl set image
deployment test test=test:1.0.1 --record
Now you can check rollout status using below command,
$ kubectl.exe rollout
status deployment
Also you can check rollout history by using below command,
$ kubectl.exe rollout
history deployment
You can use below commands to undo roll outs,
Undo to previous deployment,
$ kubectl rollout undo deployment <your deployment name>
Undo to a specific roll out revision,
$ kubectl rollout undo deployment <deployment>
--to-revision=<revision Number that you get from rollout history command
(1,2,…)>
References,
