4-Replica Set

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 Replicaset - 
 
 command to create replicaset yaml - kubectl create deployment busybox --image=busyboxxxxxxx --dry-run -o yaml > busybox.yamlx
 
 example yaml to create repliaction set (cat > rs-difintion.yaml)

apiVersion: apps/v1
kind: Replicaset
metadata:
   name:rc-controller(this is name of relica set)
   labels:
      app: my-app
      costCenter: US
      
spec:
   template:
      metadata:
         name:nginx-app(this is name of pod)
         labels:
            app: my-app
            costcenter: us
            user: hari
      spec:
         containers:
            - name:nginx-container
              image:nginx
              
   replicas: 3 (this is number of replicas)
   selector:
      matchLabels:
	     type:
		    costCenter:us
 
 command - kubectl create -f rs-definition.yaml
 
 in replicationset we can add the pods that were created before, we juust need to their labels in selector -> matchlabes - >type, then theat pod also comes under replicaset( THIS IS MAJOR DIFFERENCE BETWEEN REPLICA CONTROLLER AND REPLICA SET)
 
 
 
 command to the the replication controllers - kubectl get replicaset
 
 
 how to update the number of replicas after the resplicaset is created - 
 
 method 1 -
 
 use the command - kubectl scale --replicas=6 -f rs-definition.yaml or
 use the command - kubectl scale --replicas=6 replicaset <replicaset name>
 
 method 2 - 
 
 update the number of replicas from 3 to lets say 6 in the rs-definition.yaml and run the command -  kubectl replace -f rs-definition.yaml
 
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