Latest Docker Kubernetes Interview Questions and Answers
by Sachin, on Jul 20, 2022 8:10:50 PM
Q1. What is Docker and Kubernetes with example?
Kubernetes is an orchestration framework for Docker containers which helps expose containers as services to the outside world. For example, you can have two services − One service would contain nginx and mongoDB, and another service would contain nginx and redis.
Q2. What is the difference between Kubernetes and Docker?
Q3. How are Kubernetes and Docker related?
Docker is an open-source platform used to handle software development. Its main benefit is that it packages the settings and dependencies that the software/application needs to run into a container, which allows for portability and several other advantages. Kubernetes allows for the manual linking and orchestration of several containers, running on multiple hosts that have been created using Docker.
Q4. What are the features of Kubernetes?
- Kubernetes places control for the user where the server will host the container. It will control how to launch. So, Kubernetes automates various manual processes.
- Kubernetes manages various clusters at the same time.
- It provides various additional services like management of containers, security, networking, and storage.
- Kubernetes self-monitors the health of nodes and containers.
- With Kubernetes, users can scale resources not only vertically but also horizontally that too easily and quickly.
Q5. What is the role of Kube-apiserver?
This kind validates and provides configuration data for the API objects. It includes pods, services, replication controllers. Also, it provides REST operations and also the frontend of the cluster. This frontend cluster state is shared through which all other component interacts.
Q6. What is a node in Kubernetes?
A node is the smallest fundamental unit of computing hardware. It represents a single machine in a cluster, which could be a physical machine in a data center or a virtual machine from a cloud provider. Each machine can substitute any other machine in a Kubernetes cluster. The master in Kubernetes controls the nodes that have containers.
Q7. What is a pod in Kubernetes?
Pods are high-level structures that wrap one or more containers. This is because containers are not run directly in Kubernetes. Containers in the same pod share a local network and the same resources, allowing them to easily communicate with other containers in the same pod as if they were on the same machine while at the same time maintaining a degree of isolation.
Q8. What is a cluster of containers in Kubernetes?
A cluster of containers is a set of machine elements that are nodes. Clusters initiate specific routes so that the containers running on the nodes can communicate with each other. In Kubernetes, the container engine (not the server of the Kubernetes API) provides hosting for the API server.
Q9. What are Daemon sets?
A Daemon set is a set of pods that runs only once on a host. They are used for host layer attributes like a network or for monitoring a network, which you may not need to run on a host more than once.
Q10. What is ‘Heapster’ in Kubernetes?
A Heapster is a performance monitoring and metrics collection system for data collected by the Kublet. This aggregator is natively supported and runs like any other pod within a Kubernetes cluster, which allows it to discover and query usage data from all nodes within the cluster.
Q11. What is the Kubernetes controller manager?
The controller manager is a daemon that is used for embedding core control loops, garbage collection, and Namespace creation. It enables the running of multiple processes on the master node even though they are compiled to run as a single process.
Q12. What is etcd?
Kubernetes uses etcd as a distributed key-value store for all of its data, including metadata and configuration data, and allows nodes in Kubernetes clusters to read and write data. Although etcd was purposely built for CoreOS, it also works on a variety of operating systems (e.g., Linux, BSB, and OS X) because it is open-source. Etcd represents the state of a cluster at a specific moment in time and is a canonical hub for state management and cluster coordination of a Kubernetes cluster.
Q13. What are the different services within Kubernetes?
- Cluster IP service
- Node Port service
- External Name Creation service and
- Load Balancer service
Q14. What is the Ingress network, and how does it work?
An ingress is an object that allows users to access your Kubernetes services from outside the Kubernetes cluster. Users can configure the access by creating rules that define which inbound connections reach which services.
This is an API object that provides the routing rules to manage the external users' access to the services in the Kubernetes cluster through HTTPS/ HTTP. With this, users can easily set up the rules for routing traffic without creating a bunch of load balancers or exposing each service to the nodes.
Q15. What is Container resource monitoring?
This refers to the activity that collects the metrics and tracks the health of containerized applications and microservices environments. It helps to improve health and performance and also makes sure that they operate smoothly.
Q16. What is the difference between a replica set and a replication controller?
A replication controller is referred to as RC in short. It is a wrapper on a pod. This provides additional functionality to the pods, which offers replicas. It monitors the pods and automatically restarts them if they fail. If the node fails, this controller will respawn all the pods of that node on another node. If the pods die, they won't be spawned again unless wrapped around a replica set. Replica Set, on the other hand, is referred to as rs in short. It is told as the next-generation replication controller. This kind of support has some selector types and supports the equality-based and the set-based selectors. It allows filtering by label values and keys. To match the object, they have to satisfy all the specified label constraints.
Q17. What is a headless service?
A headless service is used to interface with service discovery mechanisms without being tied to a ClusterIP, therefore allowing you to directly reach pods without having to access them through a proxy. It is useful when neither load balancing nor a single Service IP is required.
Q18. What are federated clusters?
The aggregation of multiple clusters that treat them as a single logical cluster refers to cluster federation. In this, multiple clusters may be managed as a single cluster. They stay with the assistance of federated groups. Also, users can create various clusters within the data center or cloud and use the federation to control or manage them in one place.
Q19. What is Kubelet?
The kubelet is a service agent that controls and maintains a set of pods by watching for pod specs through the Kubernetes API server. It preserves the pod lifecycle by ensuring that a given set of containers are all running as they should. The kubelet runs on each node and enables the communication between the master and slave nodes.
Q20. What is Kubectl?
Kubectl is a CLI (command-line interface) that is used to run commands against Kubernetes clusters. As such, it controls the Kubernetes cluster manager through different create and manage commands on the Kubernetes component
Q21. What is Kube-proxy?
Kube-proxy is an implementation of a load balancer and network proxy used to support service abstraction with other networking operations. Kube-proxy is responsible for directing traffic to the right container based on IP and the port number of incoming requests.
Q22. Define Kube-api server?
The Kube-API is the frontend of the master node that exposes all the components in the API server. It provides communication between the Kubernetes nodes and the master components.