Devops

Question 1

What is Kubernetes?

Answer 1

• Kubernetes is an open-source container management platform.
• Helps you run containers at scale.
• Provides resources and Apis for managing and deploying modern applications.

Question 2

What is a Kubernetes Pod?

Answer 2

• A pod represents a runnable unit of work
• It is a thin wrapper around one or more containers.
• A pod can hold any number of containers but usually only one.

Question 3

What is a Kubernetes Node?

Answer 3

• The machines that make up a Kubernetes cluster.
• Nodes in a Kubernetes cluster may be physical or virtual.
• There are generally two types of nodes. Control-Plane-node type and work-node type

Question 4

What is a Kubernetes namespace

Answer 4

• A namespace is a virtual cluster.
• A namespace functions as a grouping mechanism inside of Kubernetes, Resources such as services, volumes, pods, replica sets, etc can easily cooperate in a namespace but the namespace provides a degree of isolation from the other parts of the cluster.

Question 5

What is a service in Kubernetes

Answer 5

• A service tells the rest of the Kubernetes environment (including other pods and replication controllers) whatservicesyour application provides.
• While pods come and go, the service IP addresses and ports remain the same. And other applications can find your service through Kubernetes service discovery.
• Persistent, provide discovery, provide load balancing, provide a stable service address, and find pods by label selector.

Question 6

What is a volume in Kubernetes?

Answer 6

• A volume represents a location where containers can access and store information.
• Pods can mount volumes like filesystems.
• For the application, the volume appears as part of the local filesystem. But volumes may be backed by local storage, Ceph, Gluster, Elastic Block Storage, and a number of other storage backends. at RippleMatch we use AWS EFS.

Question 7

What is a context in Kubernetes

Answer 7

• A context in kubernetes is an association of personal credentials, cluster information that sets it apart

Question 8

What is a DaemonSet in K8s?

Answer 8

• Implements a single instance of a pod on a worker node.
• A DaemonSet ensures that all or some Nodes run a copy of a Pod. As nodes are added to the cluster, Pods are added to them. As nodes are removed from the cluster, those Pods are garbage collected. Deleting a DaemonSet will clean up the Pods it created.

Question 9

Describe a replication controller in K8s.

Answer 9

• AReplicationControllerensures that a specified number of pod replicas are running at any one time. In other words, a ReplicationController makes sure that a pod or a homogeneous set of pods is always up and available.

Question 10

Describe the Control Plane in a K8s architecture.

Answer 10

• The control plane In a K8s architecture consists of different components but mostly provides an API server to communicate with worker nodes.
• Some notable components of the control plane.
• One or more API servers which represent the entry point for REST / kubectl
• Etcd : distributed key/value store.
• Controller-manager : Always evaluating current vs desired state of the cluster.
• Scheduler: schedules pods to workers.

Question 11

Describe the Data Plane in a K8s architecture

Answer 11

• Made up of worker nodes.
• kubelet: Acts as a conduit between the API server and the node.
• kube-proxy: Manages IP translation and routing