Kubernetes components and responsibility

Controller nodes:

• kube-apiserver
• kube-control-manager/cloud-control-manager
• kube-schduler
• calico,flannel(deprecated from 1.18),wavenet etc.,
• coreDNS
• kubelet
• kube-proxy
• Docker Engine/containerd/cri-o etc.

Compute nodes:

• kubelet
• kube-proxy
• Docker Engine/containerd/cri-o etc.,

Deployment of kubernets cluster using microk8s(ubuntu), minikube, kubeadm

• Three nodes (1 for controller and 2 for compute nodes)

POD object creation using single container and multi-container

• Understanding common networking and common storage in POD (shared namespaces)
• Sample application deployment using nginx for single container in POD
• Multi-container deployment, one for web application and second for data pull
• POD creation with initContainer advantages for pre-request
• Static POD deployment
• Deploying application from Private repository
• Resource allocation like CPU and MEMORY

ReplicationController object (RC)

• When to use replication controller?
• Disadvantages of deploying application with single POD
• Understanding template and selector parameters

ReplicaSet object (RS)

• Difference between RreplicationController and ReplicaSet
• Advantages of adding matchLabels
• When to use replicaSet?

Deployment object (deploy)

• Advantages of Deployment over POD, RC and RS
• Sample application deployment like Jenkins, nginx and capture the advantages over other objects
• Scaleout and Scalein for Deployment
• Deployment Stratagies like RollingUpdate and ReCreate difference
• Rollout, Rollback and RolloutHistory of deployment

StatefulSet object (sts)

• Difference between stateful and stateless applications
• StatefulSet application deployment advantages
• Scaleout and Scalein for Deployment
• Deployment Stratagies like RollingUpdate and OnDelete difference
• Rollout, Rollback and RolloutHistory of StatefulSet

Volumes

• Empheimeral and persistant storage differences
• Different types of volume plugins like emptyDir, hostPath, NFS etc.
• Do's and Dont's of using volumes for application deployment

PersistentVolume, PersistantVolumeClaim and StorageClass (PV and PVC)

• Advanatages of using PV over volume plugins for data dependent applications
• Static and Dynamic PV creation
• PVC assignment in POD, Deployment, Daemonset, StatefulSet objects
• StargaeClass creation for Dynamic provision
• NFS, Ceph RBD storage as examples

Services (svc)

• Exposing application running on different object through service
• Understanding difference between ClusterIP, NodePort, LoadBalancing, ExternalIP and ExternalName
• When to use these different types of services?

Secrets and configmap (secret, cm)

• How to pass sensitive data through secret like certs, password, token etc.,
• How to pass paintext data through configMap like configuration files, scripts etc.,
• Using secret in POD object through env and volumes
• Using configMap in POD object through env and volumes

Ingress (ing)

• Access application deployed with the cluster through IngressController
• Deploying Nginx IngressController
• Ingress rules creation secured and non-secure communication

Horizontal POD AutoScalling (HPA):

• HPA deployment to test auto scaling
• Deployment of metric server to achieve HPA

Scheduling and probes

• Different types of scheduling like nodename, nodeSelector, podAffinity, podAntiAffinity, nodeAffinity
• Advantages of using liveness, readiness and startup probes to verify application availability

Jobs and CronJobs

• How to achieve auto backup and restore using CronJobs for application like etcd key-value pair storage
• For kubernetes cluster
• Jobs responsibility

Calico networking

• How to migrate from flannel to calico?
• How to use flannel for POD networking and Calico for network security
• Calicoctl operations
• Network policy and global network policy

Authentication and authorization

Authentication:

• User, group and serviceaccount (token), certs
• kubeconfig entries and access multiple cluster through kubernetes config file

Authorization:

• Role Back Access Control (RBAC)
• Role, rolebinding, clusterrole, clusterrolebinding

Dashboard

• Deployment of kubernetes dashboard and creating kubernetes object through dashboard
• How to autheticate to dashboard through token and kubeconfig