Kubernetes Scale Up/Down Replica set
Kubernetes Scale Up/Down Replica set
Creat Replicaset
Create replicates with below manifest yml file
cat myrs.yml
apiVersion: apps/v1
kind: ReplicaSet
metadata:
name: frontend
labels:
app: guestbook
tier: frontend
spec:
# modify replicas according to your case
replicas: 3
selector:
matchLabels:
tier: frontend
template:
metadata:
labels:
tier: frontend
spec:
containers:
- name: php-redis
image: gcr.io/google_samples/gb-frontend:v3
to create kubernetes replicaset in kubernetes we use kubectl apply command.
master $ kubectl apply -f myrs.yml replicaset.apps/frontend created
List the Pods
list the pods with Kubectl get pods command.
master $ kubectl get pods NAME READY STATUS RESTARTS AGE frontend-98xkj 1/1 Running 0 13s frontend-cttxp 1/1 Running 0 13s frontend-xqb9z 1/1 Running 0 13s
Kubernetes Scale Up Replica set
we can scale up the pods under replicaset using kubectl scale command
master $ kubectl scale rs frontend --replicas 10 replicaset.extensions/frontend scaled master $ kubectl get pods NAME READY STATUS RESTARTS AGE frontend-4jb2x 1/1 Running 0 23s frontend-98xkj 1/1 Running 0 6m30s frontend-bpk2l 1/1 Running 0 23s frontend-cttxp 1/1 Running 0 6m30s frontend-f8b6d 1/1 Running 0 23s frontend-gkkq6 1/1 Running 0 23s frontend-glgkg 1/1 Running 0 23s frontend-mxh72 1/1 Running 0 23s frontend-wk48q 1/1 Running 0 23s frontend-xqb9z 1/1 Running 0 6m30s
here we scaled up the replicaset with 10 pods
Kubernetes Scale Down Replica set
To scale down the pods under we can use same scale command but here we have to reduce the number of replicas.
master $ kubectl scale rs frontend --replicas 2 replicaset.extensions/frontend scaled master $ kubectl get pods NAME READY STATUS RESTARTS AGE frontend-4jb2x 1/1 Terminating 0 38s frontend-98xkj 0/1 Terminating 0 6m45s frontend-bpk2l 1/1 Terminating 0 38s frontend-cttxp 1/1 Running 0 6m45s frontend-f8b6d 1/1 Terminating 0 38s frontend-gkkq6 1/1 Terminating 0 38s frontend-glgkg 0/1 Terminating 0 38s frontend-mxh72 0/1 Terminating 0 38s frontend-wk48q 1/1 Terminating 0 38s frontend-xqb9z 1/1 Running 0 6m45s master $ kubectl get pods NAME READY STATUS RESTARTS AGE frontend-4jb2x 0/1 Terminating 0 41s frontend-98xkj 0/1 Terminating 0 6m48s frontend-bpk2l 0/1 Terminating 0 41s frontend-cttxp 1/1 Running 0 6m48s frontend-gkkq6 0/1 Terminating 0 41s frontend-wk48q 0/1 Terminating 0 41s frontend-xqb9z 1/1 Running 0 6m48s master $ kubectl get pods NAME READY STATUS RESTARTS AGE frontend-cttxp 1/1 Running 0 23m frontend-xqb9z 1/1 Running 0 23m master $
finally you can see only two pods are running.
Verify the owner reference of pods
You can also verify the owner reference of these pods. using below command we can get the owner reference of this pod or how this pod is created or which controller is handling this pod
master $ kubectl get pods frontend-cttxp -o yaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: "2019-09-19T05:11:57Z"
generateName: frontend-
labels:
tier: frontend
name: frontend-cttxp
namespace: default
ownerReferences:
- apiVersion: apps/v1
blockOwnerDeletion: true
controller: true
kind: ReplicaSet
name: frontend
uid: 00e595d8-da9c-11e9-826f-0242ac110052
resourceVersion: "5705"
selfLink: /api/v1/namespaces/default/pods/frontend-cttxp
uid: 00e70999-da9c-11e9-826f-0242ac110052
spec:
containers:
- image: gcr.io/google_samples/gb-frontend:v3
imagePullPolicy: IfNotPresent
name: php-redis
resources: {}
terminationMessagePath: /dev/termination-log
terminationMessagePolicy: File
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: default-token-xmgnh
readOnly: true
dnsPolicy: ClusterFirst
enableServiceLinks: true
nodeName: node01
priority: 0
restartPolicy: Always
schedulerName: default-scheduler
securityContext: {}
serviceAccount: default
serviceAccountName: default
terminationGracePeriodSeconds: 30
tolerations:
- effect: NoExecute
key: node.kubernetes.io/not-ready
operator: Exists
tolerationSeconds: 300
- effect: NoExecute
key: node.kubernetes.io/unreachable
operator: Exists
tolerationSeconds: 300
volumes:
- name: default-token-xmgnh
secret:
defaultMode: 420
secretName: default-token-xmgnh
status:
conditions:
- lastProbeTime: null
lastTransitionTime: "2019-09-19T05:11:57Z"
status: "True"
type: Initialized
- lastProbeTime: null
lastTransitionTime: "2019-09-19T05:11:59Z"
status: "True"
type: Ready
- lastProbeTime: null
lastTransitionTime: "2019-09-19T05:11:59Z"
status: "True"
type: ContainersReady
- lastProbeTime: null
lastTransitionTime: "2019-09-19T05:11:57Z"
status: "True"
type: PodScheduled
containerStatuses:
- containerID: docker://f19f538bf188164b7e5335b4cb5c85e15cbaa08ef3995e21244b4cf08ae65dab
image: gcr.io/google_samples/gb-frontend:v3
imageID: docker-pullable://gcr.io/google_samples/gb-frontend@sha256:50b22839aaf6a18586d6751e8963cf684c27b9873ca926df22cdf88ed4452615
lastState: {}
name: php-redis
ready: true
restartCount: 0
state:
running:
startedAt: "2019-09-19T05:11:59Z"
hostIP: 172.17.0.87
phase: Running
podIP: 10.44.0.1
qosClass: BestEffort
startTime: "2019-09-19T05:11:57Z"
in the above output you can see owner reference of the pod is replicaset.
- Kubernetes Scale Up/Down Replica set
- scale down kubernetes replicaset
- Kubernetes Scale Up Replica set
- scale up replicaset
- Kubernetes Scale Down Replica set
- scale down replicaet
- scale up kuberntes replicaset