Kubernetes Overview(CKA Preparation)

Table of contents

1. Kubernetes Architecture:
   1. kubernetes components
   2. ETCD
   3. Process Flow of a POD creation:
2. Kubernetes Deployment
3. Kubernetes Services
4. Kubernetes Scheduler
   1. Labels and selectors:
   2. Annotations:
   3. Taints and Toleration: (It’s more specific to node)
   4. Node Selector: (To host Pod on particular node)
   5. Node Affinity: ( to host pod on conditional based node)
   6. Additional Info: Assigning Pods to Nodes
   7. Resource limit & Request:
5. Configure Application:
   1. Environment Variables for a Container:
   2. ConfigMap:
   3. Secrets
   4. Multi container
6. Cluster upgrade
   1. Cluster upgrade details
   2. ETCD backup and restore
7. API Groups in Kubernetes
   1. Core group
   2. Named group
8. RBAC:
   1. Roles and clusterRole:
   2. Examples:
9. Storage
   1. Direct Provisioning
   2. Static provisioning
   3. Dynamic provisioning
   4. StorageClass
   5. Volume Expansion
10. Network policy
    1. Example:
11. Ingress Controller
12. JsonPath
13. Troubleshooting
    1. Applications failures
    2. Control-plane failures
    3. Worker-nodes failures:
    4. Network issues

1)cluster Architecture Installation and configuration: 25%
  - installation
  - RBAC
  - etcd backup
  - static pod 
2)Workloads & scheduling: 15%
  - Pod,deployment,RS,how to scale them.
  - secret,configmap.
  - multiple containers.
  - request/resource limit.
  - sidecar containers
3)services and networking: 20%
  - types of services
  - ingress
  - network policies
  - coreDNS
4)Storage: 10%
  - storageclass
  - Persistenet volume.
  - Persistent volume claim.
  - Storageclass and dynamic. 
5)Troubleshooting: 30%
  - what if a node is not ready ?
  - what if a pod is frequently restarting ?
  - what if all CPU resource is used up and you need to find out which pod consumes the most and why ?
  - How to monitor certain resources?
  - troubleshoot the failed components.

K8S Architecture

Kubernetes Architecture:

kubernetes components

Master Components:
ETCD: which stores information about cluster.
Kube-scheduler: responsible for scheduling application or containers on nodes.
Controllers: Node controllers,Replication controllers etc
kube-API: responsible for manages operations.
worker Components:
Kubelet: That listen instruction from kube-api servers and manages container.
kube-proxy: Enable communication between services with clusters.

Ports and Protocols:

K8s Master ports and protocols

k8s worker node port and protocols

• Kubernetes is open source system for automating deployment,scaling and management of containerized applications.
• New kubernetes version are released in 3 month cycles.

Setup simple Kubernetes cluster on your laptop

Prerequisites

VM Hardware Requirements

8 GB of RAM (Preferably 16 GB) 50 GB Disk space

1. Check if your system support virtualization and enabled the virtualization
   Linux Find Out If CPU Support Intel VT

$ lscpu | grep -i virtualization
Virtualization:      VT-x