Kubernetes and its Components

Learn Kubernetes and its Components to understand how container orchestration, pods, nodes, and clusters work to manage modern cloud applications.

Kubernetes: (k8s) - It is used manage cluster of containerized application.

To create cluster, we require at least 3 nodes. Out of which one will master through which we can manage K8S cluster and remaining 2 are worker node.

Components of Cluster: - 

Master node Components: - 

1. 1. Kube-API server
2. 2. Controller Manager
3. 3. Kube-Schedular
4. 4. Etcd

1. 1. Kube- API Server: - We can communicate to cluster using kube api server only.  It is responsible for orchestrating all operations within cluster.
2. 2. Controller Manager: - It monitors API server and fix anything between desired one, what is available.
3.    a. Node Controller Manager: - It manages adding/removing node.
4.    b. Replication Controller: - Ensure desired no. of container are running at any time.
5. 3. Kube-Scheduler: - Specify node for POD creation.
6. 4. ETCD: - It is database of K8S, information gets saved in key value pair.

Client Components: -

1. 1. Kubelet
2. 2. Kube-proxy
3. 3. Container runtime

1.Kubelet: - It is Kubernetes agent, which runs on every node. It manages container as per instruction from master node.

2.Kube-proxy: - It ensures all rules are placed. It is responsible for all application should able to communicate with each other.

3.Container runtime: - It should be running on all node, without this container cannot be provisioned.

Kubernetes Objects and Their Uses

Kubernetes Objects are things you create and manage inside the cluster.
They tell Kubernetes what to run and how.

Pod

• • The smallest unit in Kubernetes.
• • Runs one or more containers together.

Service

• • Gives a fixed name and IP address to access Pods.
• • Also shares traffic between multiple Pods.

Deployment

• • Creates and manages Pods automatically.
• • Can increase replicas and update apps easily.

ReplicaSet

• • It ensures correct number of Pods  are always running.

Namespace

• • Divides the cluster into separate areas.
• • Helps organize apps for different teams or environments.

ConfigMap

• • Stores non-secret data like configuration settings or environment variables.

Secret

• • Stores sensitive information like passwords or API keys.

StatefulSet

• • Used for databases or stateful apps that need stable storage and names.

DaemonSet

• • Runs one Pod on every node (or selected nodes).

Ingress

• • Controls external access (HTTP/HTTPS) to your apps.
• • Can route requests based on URLs or domains.

Volume

• • Provides storage space for data used by Pods.
• • Keeps data even if a container restarts.

ResourceQuota

• • Sets limits on how much CPU, memory, or storage a namespace can use.

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Author:-

Amol Shende