55+ Top Kubernetes Interview Questions and Answers 2024. Kubernetes is derived from a Greek word that means 'captain,' 'helmsman,' or 'governor.' In the DevOps and on-premises software development realm, the term now refers to a robust set of solutions that empower operations engineers to easily scale and manage server setups.
This article on Kubernetes interview questions will help you get ready for any interview or certification exam you might need to take after completing Kubernetes training. So, let's pe in and explore the top Kubernetes interview questions and answers. Here are Kubernetes interview questions for both freshers and experienced candidates to help you land your dream job.
Top 50+ Kubernetes Interview Questions and Answers
What is Kubernetes?
Kubernetes is a container management system developed on the Google platform. Its purpose is to manage containerized applications in various environments, like physical, virtual, and cloud. Kubernetes is a flexible tool for delivering even complex applications consistently. Applications run on clusters consisting of hundreds to thousands of individual containers.
What is node in Kubernetes?
A node is the smallest hardware unit. It represents a single machine in a cluster, which can be a virtual machine from a cloud provider or a physical machine in a data center. Every machine in a Kubernetes cluster can replace other machines.
What is the role of kube scheduler?
Kube-scheduler is the default scheduler for Kubernetes. It assigns nodes to newly created pods.
What is the benefit of using Kubernetes?
Kubernetes is used because:
- It can run on-premises bare metal, OpenStack, and public clouds like Google, Azure, and AWS.
- It helps avoid vendor lock-in as it can use any vendor-specific APIs or services, except where Kubernetes provides an abstraction (e.g., load balancer and storage).
- It enables applications to be released and updated without downtime.
- Kubernetes ensures containerized apps run as intended, providing resources and tools needed for optimal performance.
- It offers features such as automated scheduling, self-healing capabilities, automated rollouts & rollbacks, horizontal scaling & load balancing, and more.
- It provides environment consistency across development, testing, and production stages.
- Infrastructure components are loosely coupled, allowing them to act as separate units.
What are vital the features of Kubernetes?
Kubernetes features include:
- Automated scheduling
- Self-healing capabilities
- Automated rollouts & rollbacks
- Horizontal scaling & load balancing
- Environment consistency for development, testing, and production
- Loosely coupled infrastructure components
- High resource utilization density
- Enterprise-ready features
- Application-centric management
- Auto-scalable infrastructure
- Predictable infrastructure creation
What types of controller managers are in K8s?
Controller manager types: 1) endpoints controller, 2) service accounts controller, 3) node controller, 4) namespace controller, 5) replication controller 6) pod controller 7) ingress controller.
Explain Kubernetes Architecture
- Master Node: The master node is a crucial component responsible for managing the Kubernetes cluster. It serves as the entry point for all administrative tasks. Multiple master nodes can exist in a cluster for fault tolerance.
- API Server: The API server is the entry point for all REST commands used to control the cluster.
- Scheduler: The scheduler assigns tasks to slave nodes. It stores resource usage information for each slave node and is responsible for distributing the workload.
- Etcd: Etcd stores configuration details and write values. It communicates with most components to receive commands and perform tasks. It also manages network rules and port forwarding activity.
- Worker/Slave nodes: Worker nodes are essential components containing all required services to manage networking between containers, communicate with the master node, and allocate resources to scheduled containers.
- Kubelet: Kubelet receives a Pod's configuration from the API server and ensures the specified containers are running.
- Docker Container: Docker containers run on each worker node, executing configured pods.
- Pods: A pod is a combination of one or more containers that logically run together on nodes.
Mention the List of services available in Kubernetes
Services available in Kubernetes include 1) Cluster IP service, 2) Load Balancer service, 3) Node Port service, and 4) External Name Creation service.
Define the List components of Kubernetes
Kubernetes has three main components:
- Node components
- Master components
What is headless service
A headless service is a service that uses IP addresses but returns associated pod IPs instead of performing load balancing.
What is the role of daemon sets
Daemon sets are a collection of pods that run on a host. They are used for host-level tasks like monitoring networks or managing simple network services.
Why we use Heapster in Kubernetes
Heapster is a metrics collection and performance monitoring system that gathers data collected by the Kubelet.
Define tasks does Kubernetes perform?
Kubernetes is like the Linux kernel for distributed systems. It abstracts the underlying hardware of nodes (servers) and provides a consistent interface for applications that consume a shared pool of resources.
What is the difference between Kubernetes and Docker Swarm?
The difference between Kubernetes and Docker Swarm is:
What are the types of Kubernetes Volumes?
Types of Kubernetes Volumes include:
- EmptyDir
- GCE persistent disk
- Flocker
- HostPath
- NFS
- ISCSI
- rbd
- PersistentVolumeClaim
- downwardAPI
Why do we use Kubernetes controller manager?
The controller manager is a daemon responsible for garbage collection, core control loops, and namespace creation. It allows running more than one process on the master node.
Why do we use namespaces in Kubernetes?
Namespaces in Kubernetes are used to pide cluster resources among users. They help in environments with multiple users or projects spread across teams, providing a scope for resources.
What are the important components of node status?
Important components of node status include:
- Condition
- Capacity
- Info
- Address
What is Ingress Network in Kubernetes?
Kubernetes Ingress network is a collection of rules that allow incoming connections into the Kubernetes cluster.
Why do we use Kubectl?
Kubectl is a command-line tool used to manage Kubernetes clusters. "Ctl" stands for "control," and it allows users to send commands to the cluster and manage Kubernetes components.
What is the Full form of GKE and why?
GKE, or Google Kubernetes Engine, is a management platform that supports clusters and Docker containers running within Google's public cloud services.
Why is a load balancer needed?
A load balancer is needed because it provides a consistent way to distribute network traffic among multiple backend services.
How to run Kubernetes locally?
You can run Kubernetes locally using Minikube, a tool that runs a single-node cluster in a virtual machine (VM) on your computer. This is an ideal solution for users who are just starting to learn Kubernetes.
What type of tools are used for container monitoring?
Container monitoring tools include:
- Heapster
- cAdvisor
- Prometheus
- InfluxDB
- Grafana
What are the Secrets of Kubernetes?
Secrets are sensitive information, like user login credentials. They are Kubernetes objects that store encrypted sensitive information, such as usernames and passwords.
What is Sematext Docker Agent?
Sematext Docker Agent is a log collection agent that also gathers events and metrics. It runs as a small container on each Docker host, collecting metrics, events, and logs for all cluster nodes and containers.
What is OpenShift?
OpenShift is a public cloud application development and hosting platform developed by Red Hat. It automates management, allowing developers to focus on writing code.
What is K8s?
K8s (K-eight characters-S) is shorthand for Kubernetes. It is an open-source orchestration framework for containerized applications.
What are federated clusters?
Federated clusters are multiple clusters managed as if they were a single cluster.
What is the difference between Docker volumes and Kubernetes Volumes?
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How do you provide API-Security on Kubernetes?
To provide API-Security on Kubernetes:
- Use the correct auth mode with API server authentication mode=Node.
- Set up kubeless to protect its API via authorization-mode=Webhook.
Ensure the kube-dashboard uses a restrictive RBAC (Role-Based Access Control) policy.
What is a ContainerCreating pod?
A ContainerCreating pod is scheduled on a node but cannot start up properly.
What is a Minikube in Kubernets?
Minikube is a tool that helps users run Kubernetes locally. It runs a single-node cluster inside a virtual machine (VM) on your computer. Developers creating applications using Kubernetes often use this tool.
Mention the uses of GKE for Knubernets
Google Kubernetes Engine (GKE) is used to:
- Create Docker container clusters
- Resize application controllers
- Update and upgrade container clusters
- Debug container clusters
Google Kubernetes Engine, GKE can create replication controllers, jobs, services, container pods, and load balancers.
What is Orchestration in Kubernetes?
Orchestration in Kubernetes is an automatic process for scheduling the work of each container. It is used for managing microservices-based applications within clusters.
What is Prometheus in Kubernetes?
Prometheus is an application for monitoring and alerting. It can connect to your systems, collect real-time metrics, compress them, and store them properly in a database.
Define some container orchestration tools?
Container orchestration tools include 1) Docker Swarm, 2) Apache Mesos, and 3) Kubernetes.
Define some Kubernetes objects?
Kubernetes objects include: 1) Pods, 2) Replication sets and controllers, 3) Jobs and cron jobs, 4) Daemon sets, 5) Distinctive identities, 6) Deployments, and 7) Stateful sets.
What are Stateful sets in Kubernetes?
Stateful sets are workload API objects used to manage stateful applications. They also manage the deployment and scaling of pods. Stateful pods store their state information and other data on disk storage connected to the stateful set.
Why We use Daemon sets?
Daemon sets are used to:
- Run storage platforms like ceph and glusterd on each node.
- Collect logs on every node, such as filebeat or fluentd.
- Monitor each node.
What is a Replica set?
A Replica set is used to maintain stable replica pods. It allows you to specify the number of identical pods available. It can be considered a replacement for the replication controller.
What are some important Kubectl commands?
Important Kubectl commands include:
- kubectl annotate
- kubectl cluster-info
- kubectl exce
- kubectl log -f
- kubectl apply
- kubectl config
- kubectl autoscale
- kubectl config current-context
- kubectl config set
Why use Kube-api server?
Kube-api server is the API server of Kubernetes used to configure and validate API objects, such as services and controllers. It provides the front end for the cluster's shared region, allowing components to interact with each other.
What are the types of Kubernetes pods?
There are two types of pods in Kubernetes:
- Single Container Pod: Created with the "run" command.
- Multicontainer pods: Created using the "create" command in Kubernetes.
What are labels in Kubernetes?
Labels are sets of key-value pairs attached to pods, replication controllers, and related services. Usually, labels are added to an object when it is created, but users can modify them during runtime.
What are the goals of a replication controller?
The goals of a replication controller are:
- Managing and controlling the pod lifecycle.
- Monitoring and verifying if the desired number of replicas are running.
- Helping users check pod statuses.
- Allowing users to modify pods and adjust their positions as needed.
What is a persistent volume?
A persistent volume is a storage unit managed by an administrator, used to manage inpidual pods in a cluster.
What is Cluster IP
Cluster IP is a Kubernetes service that provides internal access to other apps within the cluster.
Explain me about the node port
Node port service is a basic method for directing external traffic to your service. It opens a specific port on all nodes and forwards network traffic sent to this port.
Give a Definition of kubelet
Kubelet is an agent that controls and maintains groups of pods using Kubernetes specifications. It runs on each node and enables communication between master and slave nodes.
What are the top disadvantages of Kubernetes?
- The Kubernetes dashboard is not as helpful as it could be.
- Security is not very effective.
- It is complex and can reduce productivity.
- Kubernetes is more expensive than its alternatives.
What is Kube-proxy in kubernets?
Kube-proxy is both a network proxy and a load balancer implementation. It supports service abstraction used with other networking operations and is responsible for directing traffic to containers based on IP and port number.
What is PVC?
PVC stands for Persistent Volume Claim. It is storage requested by Kubernetes for pods. Users don't need to know the underlying provisioning. The claim should be created in the same namespace as the pod.
What is Kubernetes Network Policy?
Network Policy defines how pods within the same namespace communicate with each other and network endpoints.
What is Kubernetes proxy service?
Kubernetes proxy service is a service that runs on a node, making it available to external hosts.