Readme.md

Building Replica Sets

1. Create a new YAML document replica1.yaml for 10 replicas of nginx container.

   apiVersion: apps/v1
   kind: ReplicaSet
   metadata:
       name: myapp
   spec:
       replicas: 10
       selector:
       ## Identify which PODS should be part of this Set
           matchLabels:
               name: myapp
       template: # Begining of POD Template
           metadata:
           ## define name of POD (Must MATCH with Line# 10 )
               name: myapp
               labels:
                   name: myapp
           spec:
               containers:
               -   image: mahendrshinde/myweb:latest
                   name: web
                   ports:
                   -   containerPort: 80

2. Now, use following commands to deploy the replica set on cluster.

   $ kubectl apply -f replica1.yaml
   # list all pods from current replica-set, should return 10 pods
   $ kubectl get pods -l name=myapp
   # Scaling from command-line (Imperative )
   $  kubectl scale --replicas=3 -f .\replica1.yaml  
   # list all pods from current replica-set, should return 3 running pods
   # Other pods might be in terminating stage.
   $ kubectl get pods -l name=myapp

3. Test the declarative option for scaling, open replica1.yaml and change line# 11 to replicas: 5 from original replicas: 10 Now, run following command to apply and verify scaling operation.

   $ kubectl apply -f replica1.yaml
   # list all pods from current replica-set, should return 5 pods
   $ kubectl get rs
   $ kubectl get pods -l name=myapp

4. Clean-up : delete the replica set.

   $ kubectl delete -f replica1.yaml
   # Check if pods are destroyed!
   $ kubectl get pods -l name=myapp