DevOps Classroomnotes 13/Feb/2022

ReplicaSets contd..

  • Finding the ReplicaSet from Pod
  • Scaling ReplicaSets:
  • Manual Scaling: One way is to change the replicas in yaml file and apply the file again
  • Auto Scaling: When we autoscale horizontal pod autoscaler (hpa) will be created
  • AutoScaling can be done by create a manifest as well Refer Here


  • K8s namespaces provide a mechanism for isolating a group of resources with in a single cluster
  • Name of the resources should be unique with in a namespace, but not across namespaces.
  • Namespace-based scoping is applicable only for namespaced objects (Deployments, Services, Pods, Replicasets etc ) and not Cluster-wide Objects (Storage Classes, Nodes, Persistent Volumes etc)

Activity6: Create a Replicaset Which runs 2 replicas of jenkins

  • The image to be used is jenkins:1.651.2
  • replicas should be 2
  • create labels
  • app: jenkins
  • version: 1.651.2
  • port is 8080
  • Refer Here for the manifest created
  • Lets create the replica set
  • The representation of the work done by us
  • Now we can easily create a loadbalancer using k8s object called as service. The only thing service can do is group resources /select resources based on labels and give one interface for access.
  • To access the pods scaled we can use service as shown below
  • Now lets create a Service
  • Refer Here
  • Refer Here for the service manifest
  • Now if we apply the service, jenkins will be accessible on each node on port 32700 which will forward the request to service (k8s) and from there to the Pod
  • Service info is injected as env variables in all the pods to be created after server
  • Next Steps:
  • AKS and EKS
  • Service Discovery
  • Zero Downtime Deployments (rollouts and rollbacks)
  • Other => Workload Resources
  • Storage in K8s
  • RBAC

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