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ReplicaSets

replication controller

Replication Controller is the older technology that is being replaced by a ReplicaSet. ReplicaSet is the new way to setup replication. automaticaly bring new pods if needed

Load balancing & scaling

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apiVersion: v1
kind: ReplicationController
metadata:
  name: myapp-rc
  labels:
    app: myapp
    type: front-end
spec:
 template:
    metadata:
      name: myapp-pod
      labels:
        app: myapp
        type: front-end
    spec:
     containers:
     - name: nginx-container
       image: nginx
 replicas: 3

kubectl create -f replica.yml

kubectl get replicationcontroller

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apiVersion: apps/v1
kind: ReplicaSet
metadata:
  name: myapp-replicaset
  labels:
    app: myapp
    type: front-end
spec:
 template:
    metadata:
      name: myapp-pod
      labels:
        app: myapp
        type: front-end
    spec:
     containers:
     - name: nginx-container
       image: nginx
 replicas: 3
 selector:
   matchLabels:
    type: front-end

replica set needs selector definition

scale replica sets

update file

kubectl replace -f replica.yml

kubectl scale --replicas=6 -f replica.yml

kubectl scale --replicas=6 replicaset myapp-replicaset

delete replicaset

kubectl delete replicaset myapp-replicaset kubectl delete --all namespaces

get replicasetso

kubectl get replicasets.apps

describe

kubectl describe replicasets.apps new-replica-set

get version of replicaset

kubectl explain replicaset | grep VERSION

edit replica, uses editor automaticaly

kubectl edit replicaset new-replica-set