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Certified Kubernetes Administrator (CKA) Course

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  1. INTRODUCTION

    CKA Introduction
  2. CKA Exam details
  3. CKA Exam syllabus
  4. CKA Exam Registration
  5. CLUSTER ARCHITECTURE, INSTALLATION & CONFIGURATION
    Cluster Setup
    9 Topics
  6. Kubectl Aliases & Shortnames
  7. Cluster Configurations
    7 Topics
  8. Perform Cluster Version upgrade Using Kubeadm
    2 Topics
  9. etcd Backup and Restore
    1 Topic
  10. WORKLOADS
    Pods
    5 Topics
  11. Static Pods
    3 Topics
  12. Command and Arguments
    2 Topics
  13. Init Containers
    3 Topics
  14. ReplicaSets
    2 Topics
  15. Deployments
    10 Topics
  16. Jobs & Cronjobs
    5 Topics
  17. DaemonSets
    3 Topics
  18. SCHEDULING
    Labels and Selectors
    2 Topics
  19. Taints and Tolerations
    4 Topics
  20. Node Name & Node Selector
    3 Topics
  21. Node Affinity
    2 Topics
  22. IDENTITY & ACCESS MANAGEMENT
    Namespaces
    2 Topics
  23. Service Accounts
    3 Topics
  24. RBAC
    5 Topics
  25. Roles & ClusterRoles
    8 Topics
  26. STORAGE
    Volumes
    5 Topics
  27. Persistent Volumes
    5 Topics
  28. Storage Class
    3 Topics
  29. Application Configuration and Security
    Environment Variables
    4 Topics
  30. ConfigMaps
    6 Topics
  31. Secrets
    2 Topics
  32. Resource Requests & Limits
    4 Topics
  33. SERVICES, LOAD BALANCING & NETWORKING
    Services
    5 Topics
  34. Ingress
    1 Topic
  35. Network Policies
    2 Topics
  36. Other topics (need to add in relevant section)
    JSONpath
  37. Security Context
  38. Kubernetes Architecture
    1 Topic
  39. BONUS TOPICS
    StatefulSets
Lesson 8 of 39
In Progress

Perform Cluster Version upgrade Using Kubeadm

In this lesson we will look into the essential skills needed to upgrade the version of Kubernetes cluster using Kubeadm.

To upgrade a kubernetes cluster, there are two main concepts involved.

1. Node Drain

Node draining is the method of safely removing all pods from a node, getting it ready for maintenance tasks like upgrades or shutdowns.

When you initiate a node drain, Kubernetes automatically evicts and reschedules the regular application pods running on that node to other available nodes in the cluster.

Note: When you perform a node drain operation in Kubernetes, the control plane pods (also known as system pods) running on the node are not evicted. This is intentional behavior to ensure the stability and availability of the Kubernetes control plane components.

2. Node Uncordon

Uncordon is the process of marking a node as ready to schedule pods again after it has been previously drained.

You can also cordon a node. This means making the node unschedulable, but without evicting the existing pods. However, during an upgrade process, we choose to drain the node instead of just cordoning it, because we also want to evict the pods.

Cluster Upgrade Using Kubeadm

To upgrade clusters using kubeadm, we will follow the below steps:

  1. Update the Kubeadm Tool: We begin by updating the kubeadm tool to the latest version. This ensures compatibility with newer cluster versions.
  2. Upgrade the Cluster: After updating kubeadm, we upgrade the cluster to the desired version.
  3. Upgrade Order: We execute the upgrades in the following sequence:
    • Control Plane: Upgrade the control plane components first.
    • Worker Nodes: Follow with the worker nodes.
  4. Components to Upgrade:
    • Control Plane Node: Upgrade the control plane components, Kubelet, and kubectl.
    • Worker Nodes: Upgrade the Kubelet on each worker node.