Kubernetes Concepts
Visit systemdesign.us for System Design Interview Questions tagged by companies and their Solutions. Follow us on YouTube, LinkedIn, Twitter, Medium.
Kubernetes is a container orchestration platform that can be used to manage containers across multiple hosts. It provides various features such as container deployment, scaling, and management.
Why use Kubernetes?
Kubernetes can be used to manage containers in a production environment. It is a scalable platform that can be used to deploy and manage applications in a cloud-native environment.
When should you use Kubernetes?
Kubernetes is best suited for managing containers in a production environment. If you are looking to deploy and manage containers in a cloud-native environment, then Kubernetes is the right choice for you.
What are the benefits of using Kubernetes?
Some of the benefits of using Kubernetes include:
- Improved application uptime
- Reduced operational costs
- Increased developer productivity
-Improved application performance
What are the drawbacks of using Kubernetes?
Some of the drawbacks of using Kubernetes include:
- The learning curve can be steep for new users
- It can be complex to set up and manage
- There is a lack of documentation and support for some features
What are some alternatives to Kubernetes?
Some alternatives to Kubernetes include:
- Apache Mesos
- Docker Swarm
- Amazon ECS
- Microsoft Azure Container Service (ACS)
- Google Cloud Container Engine (GKE)
Kubernetes Architecture
Kubernetes is a distributed system that is composed of a set of nodes that communicate with each other. Each node in a Kubernetes cluster runs a process called kubelet which is responsible for managing the containers on that node.
The nodes in a Kubernetes cluster are managed by a central control plane which consists of a set of master nodes. The master nodes are responsible for managing the state of the cluster and providing APIs for the other nodes to interact with.
Kubernetes Components
There are several components that make up a Kubernetes cluster. These components can be divided into two categories:
- Control plane components
- Worker node components
Control plane components are responsible for managing the state of the cluster. These components include:
- kube-apiserver: The API server is the central point of interaction with the Kubernetes cluster. It exposes APIs that can be used to manipulate the resources in the cluster.
- etcd: etcd is a key-value store that is used to store the configuration data for the Kubernetes cluster.
- kube-scheduler: The scheduler is responsible for making sure that all of the pods in a Kubernetes cluster are scheduled to run on nodes that have enough resources available to run them.
- kube-controller-manager: The controller manager is a process that runs various controllers that are responsible for managing the state of the cluster.
Worker node components are responsible for running the containers in a Kubernetes cluster. These components include:
- kubelet: The kubelet is a process that runs on each worker node. It is responsible for managing the containers on that node.
- kube-proxy: The kube-proxy is a process that runs on each worker node. It is responsible for forwarding traffic to the correct pod on the node.
- container runtime: The container runtime is responsible for running the containers on the worker nodes. Kubernetes supports different container runtimes such as Docker, rkt, and CRI-O.
Kubernetes Concepts
Kubernetes is a system for managing containerized applications. It is composed of a set of nodes that communicate with each other to form a cluster. Each node in a Kubernetes cluster runs a process called kubelet which is responsible for managing the containers on that node.
The nodes in a Kubernetes cluster are managed by a central control plane which consists of a set of master nodes. The master nodes are responsible for managing the state of the cluster and providing APIs for the other nodes to interact with.
Some of the concepts that are important to understand when using Kubernetes include:
- Pods
- Replication Controllers
- Services
- Labels
- Annotations
- Namespaces
Pods are the basic unit of deployment in Kubernetes. A pod is a group of one or more containers that are deployed together on a single node. Pods can be used to deploy applications, databases, and other services.
Replication controllers are used to ensure that a certain number of pods are always running. When a pod is deleted, the replication controller will create a new one to replace it. When a new node is added to the cluster, the replication controller will schedule pods to run on the new node.
Services are used to expose applications running in pods to other parts of the cluster or to external clients. Services can be exposed using a variety of methods such as a load balancer, node port, or cluster IP.
Labels are used to identify resources in a Kubernetes cluster. Labels can be used to select groups of resources for various operations such as deletion or modification.
Annotations are used to store arbitrary metadata on resources in a Kubernetes cluster. Annotations can be used for things like storing information about when a resource was last updated or specifying who is responsible for managing a resource.
Namespaces are used to logically group resources in a Kubernetes cluster. Namespaces can be used to isolate applications from each other or to provide separate environments for development, testing, and production.
In this section, we will discuss some of the important concepts in Kubernetes.
Cluster: A group of nodes (physical or virtual machines) that are used to run applications is called a cluster. Each node in a cluster runs a agent called kubelet which communicates with the master node. The master node controls the entire cluster and provides APIs for managing the applications.
Node: A node is a physical or virtual machine that runs one or more pods. Pods are logical units of deployment in Kubernetes and can be thought of as containers on steroids. Each pod has its own IP address and can contain one or more containers.
Deployment: A deployment is a way to describe a desired state for your application. It defines how many replicas of your application should be running and ensures that the correct number of replicas are always running.
Service: A service is a logical grouping of pods that enables communication between them. Services can be exposed internally or externally using a load balancer.
Ingress: An ingress is a way to expose services externally from a Kubernetes cluster. It provides load balancing, SSL termination, and name-based virtual hosting.
Kubectl: Kubectl is the command line interface for Kubernetes. It can be used to manage applications in a Kubernetes cluster.
Visit systemdesign.us for System Design Interview Questions tagged by companies and their Solutions. Follow us on YouTube, LinkedIn, Twitter, Medium.
