Explore topic-wise InterviewSolutions in Current Affairs.

This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.

1.

Copy files and directories to and from containers

Answer»
CommandsDescription
kubectl cp /tmp/foo_dir my-pod:/tmp/bar_dirCopy /tmp/foo_dir local directory to /tmp/bar_dir in a remote pod in the current namespace.
kubectl cp /tmp/foo my-pod:/tmp/bar -c my-containerCopy /tmp/foo local file to /tmp/bar in a remote pod in a specific container.
kubectl cp /tmp/foo my-namespace/my-pod:/tmp/barCopy /tmp/foo local file to /tmp/bar in a remote pod in a specific container.
kubectl cp my-namespace/my-pod:/tmp/foo /tmp/barCopy /tmp/foo from a remote pod to /tmp/bar locally.
Conclusion

Kubernetes is a portable, extensible, open-source platform for managing containerization workloads and services that facilitates both declarative configuration and automation, letting you run distributed systems resiliently with scaling and failover for your application.

Knowing Kubernetes is a must-have skill whether you are a developer, a tester or a DevOps engineer, I hope this article has helped you out. If you are preparing for your interviews as a fresher or if you are an experienced person looking to switch jobs, then InterviewBit is the right place to start. It has several tracks including Programming, System Design, Puzzles and Scripting along with company-specific preparation guides and fast track courses.

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Discussion
2.

Interacting with Deployments and Services

Answer»
CommandsDescription
kubectl logs deploy/my-deploymentDump Pod logs for a Deployment (single-container case).
kubectl logs deploy/my-deployment -c my-containdump Pod logs for a Deployment (multi-container case).
kubectl port-forward svc/my-service 5000To listen on local port 5000 and forward to port 5000 on Service backend.
kubectl port-forward deploy/my-deployment 5000:6000To listen on local port 5000 and forward to port 6000 on a Pod created by <my-deployment>.
kubectl exec deploy/my-deployment -- lsTo run command in first Pod and first container in Deployment (single- or multi-container cases).
Discussion
3.

For Cluster Introspection

Answer»
CommandsDescription
kubectl versionTo get the information related to the version.
kubectl cluster-infoTo get the information related to the cluster.
kubectl config g viewTo get the configuration details.
kubectl describe node <node_name>To get the information about a node.
Discussion
4.

Changing Resource Attributes

Answer»

Taints: They ensure that pods are not placed on inappropriate nodes.

CommandDescription
kubectl taint <node_name><taint_name>This is used to update the taints on one or more nodes.

Labels: They are used to identify pods.

CommandDescription
kubectl label pod <pod_name> Add or update the label of a pod
Discussion
5.

Kubernetes Commands

Answer»

Viewing Resource Information:

1. Nodes: 

ShortCode = no

A Node is a worker machine in Kubernetes and may be either a virtual or a physical machine, depending on the cluster. Each Node is managed by the control plane. A Node can have multiple pods, and the Kubernetes control plane automatically handles scheduling the pods across the Nodes in the cluster.

CommandsDescription
kubectl get nodeTo list down all worker nodes.
kubectl delete node <node_name>Delete the given node in cluster.
kubectl top nodeShow metrics for a given node.
kubectl describe nodes | grep ALLOCATED -A 5Describe all the nodes in verbose.
kubectl get pods -o wide | grep <node_name>List all pods in the current namespace, with more details.
kubectl get no -o wideList all the nodes with mode details.
kubectl describe noDescribe the given node in verbose.
kubectl annotate node <node_name>Add an annotation for the given node.
kubectl uncordon node <node_name>Mark my-node as schedulable.
kubectl label nodeAdd a label to given node

2. Pods

Shortcode = po

Pods are the smallest deployable units of computing that you can create and manage in Kubernetes.

CommandsDescription
kubectl get poTo list the available pods in the default namespace.
kubectl describe pod <pod_name>To list the detailed description of pod.
kubectl delete pod <pod_name>To delete a pod with the name.
kubectl create pod <pod_name>To create a pod with the name.
Kubectl get pod -n <name_space>To list all the pods in a namespace.
Kubectl create pod <pod_name> -n <name_space>To create a pod with the name in a namespace.

3. Namespaces

Shortcode = ns

In Kubernetes, namespaces provide a mechanism for isolating groups of resources within a single cluster. Names of resources need to be unique within a namespace, but not across namespaces.

CommandsDescription
kubectl create namespace <namespace_name>To create a namespace by the given name.
kubectl get namespaceTo list the current namespace in a cluster.
kubectl describe namespace <namespace_name>To display the detailed state of one or more namespaces.
kubectl delete namespace <namespace_name>To delete a namespace.
kubectl edit namespace <namespace_name>To edit and update the definition of a namespace.

4. Services

Shortcode = services

In Kubernetes, a Service is an abstraction which defines a logical set of Pods and a policy by which to access them (sometimes this pattern is called a micro-service).

CommandsDescription
kubectl get servicesTo list one or more services.
kubectl describe services <services_name>To list the detailed display of services.
kubectl delete services -o wideTo delete all the services.
kubectl delete service < service_name>To delete a particular service.

5. Deployments

A Deployment provides declarative updates for Pods and ReplicaSets.The typical use case of deployments are to create a deployment to rollout a ReplicaSet, declare the new state of the pods and rolling back to an earlier deployment revision.

CommandsDescription
kubectl create deployment <deployment_name>To create a new deployment.
kubectl get deploymentTo list one or more deployments.
kubectl describe deployment <deployment_name>To list a detailed state of one or more deployments.
kubectl delete deployment<deployment_name>To delete a deployment.

6. DaemonSets

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.

CommandDescription
kubectl get dsTo list out all the daemon sets.
kubectl get ds -all-namespacesTo list out the daemon sets in a namespace.
kubectl describe ds [daemonset_name][namespace_name]To list out the detailed information for a daemon set inside a namespace.

7. Events

Kubernetes events allow us to paint a performative picture of the clusters.

CommandsDescription
kubectl get eventsTo list down the recent events for all the resources in the system.
kubectl get events --field-selector involvedObject.kind != PodTo list down all the events except the pod events.
kubectl get events --field-selector type != NormalTo filter out normal events from a list of events.

8. Logs

Logs are useful when debugging problems and monitoring cluster activity. They help to understand what is happening inside the application.

CommandsDescription
kubectl logs <pod_name>To display the logs for a Pod with the given name.
kubectl logs --since=1h <pod_name>To display the logs of last 1 hour for the pod with the given name.
kubectl logs --tail-20 <pod_name>To display the most recent 20 lines of logs.
kubectl logs -c <container_name> <pod_name>To display the logs for a container in a pod with the given names.
kubectl logs <pod_name> pod.logTo save the logs into a file named as pod.log.

9. ReplicaSets

A ReplicaSet's purpose is to maintain a stable set of replica Pods running at any given time. As such, it is often used to guarantee the availability of a specified number of identical Pods.

CommandsDescription
kubectl get replicasetsTo List down the ReplicaSets.
kubectl describe replicasets <replicaset_name>To list down the detailed state of one or more ReplicaSets.
kubectl scale --replace=[x]To scale a replica set.

10. Service Accounts

A service account provides an identity for processes that run in a Pod.

CommandsDescription
kubectl get serviceaccountsTo List Service Accounts.
kubectl describe serviceaccountsTo list the detailed state of one or more service accounts.
kubectl replace serviceaccountsTo replace a service account.
kubectl delete serviceaccounts <name>To delete a service account.
Discussion
6.

Kubernetes Terminology

Answer»

Terms that you should be familiar with before starting off with Kubernetes are enlisted below:

TermsExplanation
ClusterIt can be thought of as a group of physical or virtual servers where Kubernetes is installed.
Nodes

There are two types of Nodes, 



  1. Master node is a physical or virtual server that is used to control the Kubernetes cluster.

  2. Worker node is the physical or virtual server where workload runs in given container technology.


PodsThe group of containers that shares the same network namespaces.
LabelsThese are the key-value pairs defined by the user and associated with Pods.
MasterIt controls plane components to provide access points for admins to manage the cluster workloads.
ServiceIt can be viewed as an abstraction that serves as a proxy for a group of Pods performing a "service".

Since now we have a fair understanding of what Kubernetes is, let's now jump to the cheat sheet.
Discussion
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