Debug School: Ayush Sinha

k8s Assignment 2

Ayush Sinha — Tue, 18 Oct 2022 07:06:00 +0000

Kubernetes Architecture

A kubernetes cluster consists of a master node(s) (aka control plane) and worker node(s). Job of the master node is to manage the worker nodes. This is done through different components running in the form of pods on it. Job of the worker node is to run the workload (i.e. application). These applications are running inside container which with some other components form a pod.

Master Node

Also known as Control plane.
It's job is to manage the worker nodes.
To help the master node in managing the worker nodes, there are 4 different components: API Server, scheduler, controller manager and etcd.

Worker Node

It's job is to run the applications in the form of pods.
It consists of kubelet, kube-proxy, container-runtime, pods, etc.

10 problems solved by kubernetes

Ayush Sinha — Tue, 18 Oct 2022 04:53:07 +0000

Orchestration of millions of containers running in parallel.
Rolling out new version upgrade without manual intervention.
Automatic scaling of the infrastructure based on the workload.
Cost savings because of the autoscaling feature.
Provides High Availability (HA) for the running applications.
Support for managing applications on multiple cloud.
Make it easy for porting of application from one infrastructure to other.
Lifecycle management of services (running in containers form) for the microservice based applications.
Allows developers to focus on the application logic rather than focusing on the management of the applications to be run.
Provide load balancing feature to handle large incoming requests.

Docker Assignment

Ayush Sinha — Mon, 17 Oct 2022 20:20:33 +0000

Docker pause & unpause commands

docker pause

 * This command is used to suspend / stay / pause all the 
   running processes in the given container. 
 * When the docker daemon is asked to pause the 
   container, it performs certain state checks on the 
   container such as:
     1. Whether the container is in running state or not. 
     2. Whether the container is already paused. 
     3. Whether the container is in restarting phase. 
 * Command: docker pause container_id/container_name

docker unpause

* This command moves the status of the container to 
  "Running" from "Paused". 
* Command: docker unpause container_id/container_name

Docker stop & kill commands

docker stop

  * This command issues a SIGTERM signal which stops the 
    program gracefully unlike the KILL command. 
  * Command: docker stop container_id/container_name

docker kill

  * This command issues a SIGKILL signal which stops the 
    program abruptly by killing the entry process 
    (process belonging to pid1). 
  * Command: docker kill container_id/container_name