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Kubernetes ⚡

Lavakush Biyani's photo
Lavakush Biyani
·May 9, 2022·

5 min read

Kubernetes ⚡

What is Kubernetes ☸?

  • In simpler words Kubernetes is an opensource container orchestration tool, for automating, scaling and deployment and management of containerized applications.
  • Kubernetes is also represented as k8S . So here 8 represents the simple quantity of letters in between the starting and ending collateral.
  • Kubernetes was developed by Google in 2014.
  • Kubernetes helps us to manage containerized applications in different deployment environments like physical, virtual, hybrid ,cloud environments.

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Kubernetes Features 🏆

  • In the recent years, due to the increase in usage of containers the demand for a proper way of managing those hundreds of containers has came into existence.

1) High availability or no down time.

2) Auto-scaling of the deployed applications.

3) Automatic replacement of the failed containers.

4) Distribution of load across many servers and maintaining a balance.

5) Monitoring and health check of the containers.

6) Automated rollbacks and rollouts.

7) Self-healing

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Kubernetes Components ⚡

  • Kubernetes has tons of components, but we mostly work with a quite a bit of it.

  • Kubernetes components helps us in deploying the applications.

1) Node and Pod :

  • Kubernetes consists of two types of node master node and worker node. A node is a simple server or a virtual machine
  • The smallest unit of kubernetes is called pod.

  • Pod creates a running environment or a layer on the top of the container.

  • Each pod has its own IP address and each pod communicate with each other through IP address.

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2) Service :

  • It is basically a permanent IP address which is attached to the each pod.

  • The best thing about the service is even if the pod dies, the service and its IP address will not be get affected and still works.

  • Service is also like a load balancer.

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3) Config Map and Secret :

  • Config Map usually contains the configuration data like URL's of the database and some other services which we usually use in kubernetes.

  • The secret is just like config map but the main difference between config map and secret is that's used to store the secret data credentials in base64 encoded.

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4) Volumes :

  • When we restart the pod the data which is stored gets lost which is a problematic, to solve this problem there is an another kubernetes component called Volumes.

  • Volumes attaches a physically storage on a hard drive to the pod and it could be on the remote, outside of the k8s cluster.

5) Deployment :

  • At any moment of time It acts like a blue print for the pods and we practically work with the deployments to create replicas which is used to scale up or down the number of replicas of the pods.

  • Deployments are another layer of abstraction on the top of pods which makes us more convenient to work with the pods.

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6) Ingress :

  • Ingress is used to route the traffic into the cluster.

  • It also allows access to the kubernetes services from outside the cluster.

After having sneak peek into the kubernetes components lets dive into the kubernetes architecture.

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Kubernetes architecture 🏗️

  • Kubernetes architecture mainly revolves in between the control plane and the nodes in the cluster.

  • The control plane includes the K8 API server, scheduler, control manager, etcd.

  • Kubernetes node components include a container run time engine (or) docker, kubelet,kubelet proxy.

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Lets get deep dive into each of it

1) API server : It is just like a cluster gateway which gets initial updates of the cluster and queries.

-> It authenticates and authorizes the requests.

->Before creating any new pod or service we have to talk to the API server which validates the requests whether to create a pod or not.

2)Scheduler : The name itself suggests the meaning to it. Scheduler has the whole intelligent way of deciding on which worker node the next pod should be scheduled.

-> It also keeps an eye on how much CPU or RAM space the pod is occupying in the system.

3) Control Manager : It is a daemon which runs the kubernetes cluster using several controller functions.

-> It detects the cluster changes like whenever the pod dies the controller manager detects it and recovers it as soon as possible.

4) etcd : It is just like the cluster brain 🧠 Any changes in the cluster get stored on the key value store.

-> It is also used to store some other config details like ConfigMaps, secrets ,subnets.

-> The main thing is that application data is not gets stored in the etcd.

Now coming on to the Nodes

On every node the 3 processes must be installed for surely they are kubelet, kubeproxy, container run-time.

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1) Kubelet: It interacts with both the container and the node and it is reponsible for starting and running the pod.

-> The kubelet receives the pod specifications through the API server and executes the action. It also assures the containers are healthy and running.

2) Kube-proxy: It facilitates the kubernetes networking services and it makes sure that services are available for external end points.

3) Container Runtime: Every node runs and manages the container life cycles using a container run time.Kubernetes open container supports Docker, rktnetes.

Pic sources: Google, Learn k8s

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Protip 💡

At the Begining kubernetes looks overwhelmed to you with many components and objects, but this topic interests me a lot and being consistent in learning is the best way to master it ✅.