Preparing For A Kubernetes Job Interview? We’ve Got You
Are you preparing for a job interview that includes AWS Kubernetes? We’ve got you! In this article, we’ll provide an interview guide that includes common Kubernetes interview questions to expect.
1. What is Kubernetes and why is it important for DevOps?
Kubernetes is an open-source container orchestration platform that automates deploying, scaling, and managing containerized applications. It’s important for DevOps because it helps streamline the process of deploying and managing applications, enabling faster development and delivery of software.
2. How does Kubernetes work with AWS?
Kubernetes can be deployed on AWS using Amazon Elastic Kubernetes Service (EKS), a managed service that makes it easy to run Kubernetes on AWS without needing to install and operate the Kubernetes control plane. EKS integrates with other AWS services like Elastic Load Balancing, Amazon RDS, and AWS Identity and Access Management (IAM) to provide a seamless experience for deploying and managing containerized applications.
3. What are the key components of Kubernetes architecture?
The key components of Kubernetes architecture are:
- Nodes: the physical or virtual machines that run containerized applications.
- Control Plane: the set of components that manage the overall state of the cluster including the API server, etcd, controller manager, and scheduler.
- Pods: the smallest and simplest unit in the Kubernetes object model, which represents a single instance of a running process in a cluster.
- Services: a way to expose an application running on a set of Pods as a network service.
- Ingress: an API object that manages external access to the services in a cluster, typically through HTTP.
4. What is the role of a Kubernetes Master?
The Kubernetes Master, also known as the Control Plane, is responsible for managing the overall state of the cluster. It includes the API server, which exposes the Kubernetes API; etcd, which stores the configuration data; the controller manager, which runs controllers that regulate the state of the cluster; and the scheduler, which assigns Pods to Nodes.
5. What is a Kubernetes Namespace and why is it useful?
A Kubernetes Namespace is a way to divide cluster resources among multiple users or teams. It provides a scope for resource names, allowing you to organize and isolate resources based on their purpose or ownership. Namespaces are useful for managing large clusters with many users, as they help prevent naming conflicts and facilitate resource sharing and access control.
6. How do you deploy an application on Kubernetes?
To deploy an application on Kubernetes, you need to create a set of configuration files that define the desired state of your application, including the container images, replicas, and network settings. These files are typically written in YAML format and include:
- Deployment: describes the desired state of the application, including the container image, replicas, and update strategy.
- Service: exposes the application to the network, either within the cluster or externally.
- Ingress (optional): manages external access to the services in a cluster, typically through HTTP.
Once you’ve created the configuration files, you can use the
kubectl command-line tool to apply them to your cluster.
7. What is a Kubernetes ConfigMap and how is it used?
A Kubernetes ConfigMap is an API object that allows you to store non-confidential configuration data in key–value pairs. It can be used to separate configuration data from container images, making it easier to update and manage application configurations without rebuilding the images. ConfigMaps can be consumed by Pods as environment variables, command-line arguments, or mounted as files in a volume.
8. What is a Kubernetes Secret and how does it differ from a ConfigMap?
A Kubernetes Secret is an API object that allows you to store sensitive data, such as passwords, tokens, or keys, in a more secure way than using a ConfigMap. Secrets are encrypted at rest and can be accessed only by authorized Pods. Like ConfigMaps, Secrets can be consumed by Pods as environment variables, command-line arguments, or mounted as files in a volume. The main difference between Secrets and ConfigMaps is the level of security provided for storing sensitive data.
9. How do you scale applications in Kubernetes?
In Kubernetes, you can scale applications by adjusting the number of replicas specified in the Deployment configuration. You can either manually update the replica count or use the Horizontal Pod Autoscaler (HPA) to automatically scale the number of Pods based on CPU utilization or custom metrics. Additionally, you can use the Cluster Autoscaler to automatically adjust the size of the underlying node pool based on the resource requirements of your applications.
10. What are Kubernetes best practices for security?
Some Kubernetes best practices for security include:
- Limiting access to the Kubernetes API by using Role-Based Access Control (RBAC) and restricting network access to the control plane.
- Securing container images by using trusted base images, scanning for vulnerabilities, and signing images.
- Using network policies to control traffic between Pods and isolate sensitive workloads.
- Encrypting Secrets at rest and in transit, and using Kubernetes-native secret management solutions like AWS Secrets Manager or Vault by HashiCorp to protect sensitive information.
11. What is the difference between a Kubernetes cluster and a node?
A Kubernetes cluster is made up of one or more nodes, each of which runs one or more containers. The node is the underlying physical or virtual machine that runs these containers and provides the necessary resources (such as CPU and memory) for operate.
12. Can you explain how Kubernetes handles networking between pods?
In order to enable communication between pods running in a Kubernetes cluster, Kubernetes implements what’s known as a pod network. This network typically uses overlay networks based on technologies like VXLAN or IP-in-IP tunnels to allow pods running on different nodes to communicate with each other as if they were on the same physical host.
13. How does scaling work in Kubernetes?
Scaling can be achieved by changing the desired number of replicas for any given deployment, replica set, stateful set, daemon set, job, etc. Once this configuration change has been applied, the controller responsible for managing that resource will make sure new instances are created (or existing ones are terminated), until the desired state is reached.
14. How do you ensure high availability in your AWS EKS cluster?
The best way to ensure high availability in an Amazon EKS Cluster is by distributing it across multiple Availability Zones within a single Region. By deploying applications across zones you increase their resiliency against failures along with enabling self-healing using Liveness Probes. Horizontal auto-scaling and rolling updates can also play role.
Other methods could include reducing downtime during deployments by implementing green/blue deploys through services such Nginx, ingress controllers, potentially using Canary releases (allowing safe trial with adjustments), as well as backup and recovery solutions from disaster recovery steps such as AWS EBS for data persistence and disaster recovery.
15. How does Kubernetes handle persistent storage?
Kubernetes abstracts the underlying storage infrastructure using Persistent Volumes (PVs) and Persistent Volume Claims (PVCs). A PV represents a physical piece of storage in the cluster while PVC represents a request for that specific type of resource. When a pod needs access to some persistent storage, it makes a reference through the PVC definition which is then bound by the PV controller to an available PV. The PV gets mounted to desired nodes of Kubernetes-defined pods and any relevant functionality will be managed from your respective setup including backup/recovery procedures at pod level or node level as per your preference.
There you have it: fifteen answers to potential questions for a job interview involving Kubernetes. We hope these answers will help you get your next job!