Debug School: Harish G

Deman set, Job and CronJob, ConfigMap, Services and Ingress Controller by Harish

Harish G — Wed, 18 Oct 2023 12:15:16 +0000

Deman set

It is used to instantiate pod in every available node.
Min and max node created using deman set is 1.

Job and CronJob’s

Job is the resource which runs the task and monitor it to complete.
Cron job is the resource which runs the task and repeat it on defined schedule.

ConfigMap

Config map allows us to create and store the data as key-value pair.
It will be accessible through out all the nodes.

Services

Services are acts as a load balancer in the kubernetes cluster.
We ClusterIP, NodePort, LoadBalancer services.
CluserIp service is used when we need to access the pod with in the cluster.
NodePort service is used when we need to access the pod out of the cluster.
LoadBalancer service is used when we need to access the different or multiple pods.

Ingress Controller

Ingress is the rules specified to the controller.
Ingress controller is an Application Load balancer.

What is Namespace,Pod's,ReplicationController, Replica set and Deployment by Harish

Harish G — Tue, 17 Oct 2023 12:03:00 +0000

Namespace

Namespace is used to Structuralize the resources of the Clustered Horizontally. eg.. ram, diskspace, cpu etc
Using Name space we can restrict the access to other users and isolate the resources.

Pod

Pod is the smallest entity of Kubernetes.
Pod life cycle is – Pending, Running, Failed.
Pod can’t be created they can only be instantiated.
we can go inside the container using pod exec.
we can get container logs using kubectl logs.

ReplicationController and Replica Set

Replicationcontroller is used to instantiate multiple pods and control the running pods.
Replica Set is the updated version of ReplicationController. ## Deployment
Deployment is used to instantiate pod and control the running pods using help of Replica Set and pod.

What is Pod by Harish

Harish G — Mon, 16 Oct 2023 11:56:55 +0000

What is Pod?

Pod is the smallest entity of Kubernetes.
Pod life cycle is – Pending, Running, Failed.
Pod can’t be created they can only be instantiated.
Pod can be configured in multiple ways eg. 1 pod having 1 container, 1 pod having 2 container , 1 cluster having 2 or more containers
Ip is assigned to pod all containers in pod will have same IP address.
In same pod having similar or same container is bad design.
Containers inside the pod can communicate through localhost or with pod IP.
To access the container, use the pod IP with port to access application.
Pod can’t be deleted or paused.
Pod helps us in scaling the application.
Pod is instantiated by kubelet.
Pod can we instantiated using the yml file.
Type = pod will specify the yml to create pod.

What is Kubernetes by Harish

Harish G — Mon, 16 Oct 2023 07:33:48 +0000

What is Kubernetes?

Kubernetes (or k8s) is an orchestrator tool for containers. which helps to manage the containers in production environment.

Why do we need Kubernetes?

Kubernetes is used for managing the container. Which helps us in creating more reliable and scalable application. In production environment creating the application to be online and be available for large number of users is more important with the help of Kubernetes we can make our application more efficient and serve our customer. Kubernetes is helpful while upgrading out application with out any down time which help’s the us to role out any changes at any point of time. With the help of the role back feature we can roll back the upgrade or down gradle the feature with zero down time.
Overall, the Kubernetes helps us in managing our application effortlessly and keep us healthy, wealthy, and happy.

How Kubernetes Works?

As we discussed Kubernetes is an orchestrator tool for containers. Which will have cluster which consist of master and worker node. The master helps us in managing the worker node activities such as creating pods, maintaining pods etc in worker node, based on the instruction given by developer in YAML.

Explain each component of Kubernetes Architecture?

Kubernetes Cluster have 2 major components.

Master or control plain.
Worker Master has 4 main components – ApiServer, Persistent volume, Controller, Scheduler Worker has 3 main component – Kubelet, Kube-proxy, Container.d

Master or control plain. a. ApiServer – This is the only gateway to communicate with in the cluster. All the requests are passed from apiServer. b. Persistent volume(etcd) – This is the source of truth in k8s. this is the memory unit of the Kubernetes. c. Controller – This is the watcher in Kubernetes. Which keeps listening in loop with all the components in k8s and getting the data or stat. d. Scheduler – This helps in scheduling the container or tasks in cluster.
Worker a. Kubelet – This is used in managing the pod. Eg. Initializing the pods etc b. Proxy – This is the network component of pod which helps to communicate between the different pod, host etc. c. Container.d – This the containerizing host which help to run the docker container on node or worker.