Update Sunlife_Notes

Author: onlineTrainingguy

Sunlife_Notes

@@ -1281,3 +1281,148 @@ kubectl get rc
 
 kubectl get po -l app=nginx-app
 -------------------------------------------------------------------
+
+-------------------------Replicaset----------------------------
+A ReplicaSet's purpose is to maintain a stable set of replica Pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods.
+
+Replication Controller(Equality based)
+
+ReplicaSet (Set Based
+
+It uses the operators ( =, ==, !=)
+
+Operators ( in, notin,exists)
+
+Example env=prod, env!=stag
+
+Env in(prod)
+
+Command Line
+
+kubectl get pods -l env=prod
+
+Kubectl get pods ‘env in(prod,qa)’
+
+Manifest
+
+selector:
+
+    app: nginx-app
+
+ 
+
+  selector:
+
+    matchLabels:
+
+      app: nginx-app
+
+    matchExpressions:
+
+      - {key: tier, operator: In, values: [frontend]}
+
+
+LAB
+
+
+
+# nginx-rs.yaml
+apiVersion: apps/v1
+kind: ReplicaSet
+metadata:
+  name: nginx-rs
+spec:
+  replicas: 3
+  template:
+    metadata:
+      name: nginx-pod
+      labels:
+        app: nginx-app
+        tier: frontend
+    spec:
+      containers:
+      - name: nginx-container
+        image: nginx
+        ports:
+        - containerPort: 80
+  selector:
+    matchLabels:
+      app: nginx-app
+    matchExpressions:
+      - {key: tier, operator: In, values: [frontend]}
+
+
+
+
+*******************************************************************
+
+# 2. Create and display replicaset
+
+
+
+kubectl create -f nginx-rs.yaml
+
+kubectl get po -o wide
+
+kubectl get po -l app=nginx-app
+
+kubectl get rs nginx-rs -o wide
+
+kubectl describe rs nginx-rs
+
+kubectl get po -l 'tier in (frontend)'
+
+*******************************************************************
+
+# 3. Automatic Pod Reschedule 
+
+
+
+kubectl get po -o wide --watch
+
+kubectl get po -o wide
+
+kubectl get nodes
+
+
+
+*******************************************************************
+
+# 4. Scale up pods
+
+
+
+kubectl scale rs nginx-rs --replicas=5
+
+kubectl get rs nginx-rs -o wide
+
+kubectl get po -o wide
+
+
+
+*******************************************************************
+
+# 5. Scale down pods
+
+
+
+kubectl scale rs nginx-rs --replicas=3
+
+kubectl get rs nginx-rs -o wide
+
+kubectl get po -o wide
+
+
+
+*******************************************************************
+
+# 6. Cleanup
+
+
+
+kubectl delete -f nginx-rs.yaml
+
+kubectl get rs
+
+kubectl get po -l app=nginx-app
+----------------------------------------------------------------