Debug School: Mohan

what is pod

Mohan — Fri, 21 Jul 2023 13:23:58 +0000

A pod is a logical wrapper entity for a container to execute on a K8s cluster,”

How Kubernetes work

Mohan — Fri, 21 Jul 2023 13:22:31 +0000

Kubernetes is a platform for managing containerized applications1. It uses a cluster of machines, called nodes, to run and organize containers2. Kubernetes provides APIs to control and manage how containers are deployed, scaled, and load balanced13. Kubernetes works like an operating system that treats the cluster as a single pool of resources4. Kubernetes is a container-orchestration system, which means it does not create containers, but manages their lifecycle35.

why we need K8s

Mohan — Fri, 21 Jul 2023 13:21:10 +0000

Kubernetes is an open-source container orchestration tool that can simplify the management of containers and make the management process more effective and cost-efficient1.

What is Kubernetes?

Mohan — Fri, 21 Jul 2023 13:20:56 +0000

Container Orchestration tool

How can you share a Docker image with others and pull an image from a Docker registry?

Mohan — Tue, 18 Jul 2023 12:27:41 +0000

There are three ways to share a Docker image with others123:
Export the container as a tar file using . Share the tar file with the person you want to share the image with. They can create a container by .
Save the image as a tar bundle, copy the tar bundle to the remote machine, and load the tar bundle as a Docker image.
Push the image to a Docker registry. The default registry is Docker Hub, which allows you to publicly share images and gives you one private repository too.

How can you inspect the contents of a Docker container and the changes made to a container while it was running?

Mohan — Tue, 18 Jul 2023 12:26:56 +0000

docker inspect design_patterns will show you some info about the running container or just get into the container docker exec -it design_patterns bash this will drop you into a bash shell into the container, then you can inspect the current state with regular bash commands

What is a Dockerfile and how do you use it to create a Docker image?

Mohan — Tue, 18 Jul 2023 12:25:51 +0000

A Dockerfile is a text file that contains all the commands, in order, needed to build a customized docker image on top of a basic docker image. The docker build command processes this file and generates a docker image in your local image cache, which you can then run or push to a repository. You can specify the name of your custom docker image with the -t tag. The Dockerfile syntax and instructions are documented at Dockerfile reference1.

How do you create a Docker image and run a Docker container?

Mohan — Tue, 18 Jul 2023 12:24:35 +0000

$ docker images
REPOSITORY TAG ID CREATED SIZE
ubuntu 12.04 8dbd9e392a96 4 months ago 131.5 MB (virtual 131.5 MB)
With a name (let's use Ubuntu):

$ docker run -i -t ubuntu:12.04 /bin/bash
Without a name, just using the ID:

$ docker run -i -t 8dbd9e392a96 /bin/bash

What is a Docker image and how is it different from a Docker container?

Mohan — Tue, 18 Jul 2023 12:23:09 +0000

What is Docker Image?
The concept of Image and Container is like class and object, in which an object is an instance of a class, and a class is the blueprint of the object. Images are different in Virtual Machines and dockers. In virtual machines, images are just snapshots of running virtual machines at different points in time, but Docker images are a little bit different. The most important and major difference is that Docker images are immutable. That is they can not be changed. In the real world, it happens a lot that software works on one computer but it does not work on others due to different environments. This issue is completely solved by docker images and using this, the application will work the same on everyone’s PC. Every developer on a team will have the exact same development instance. Each testing instance is exactly the same as the development instance. Your production instance is exactly the same as the testing instance. Also, developers around the world can share their Docker images on a platform called DockerHUB.

What is Docker Container?
They are actually Docker Virtual Machines but are commonly called Docker Containers. If a Docker image is a map of the house, then a Docker container is an actually built house, or in other words, we can call it an instance of an image. As per the official website, a container is a runnable instance of an image. You can create, start, stop, move, or delete a container using Docker API or CLI. You can connect a container to one or more networks, attach storage to it, or even create a new image based on its current state. An application runs using a cluster of containers that are self-isolated from one another and also from the host machine where they are running.

What is Docker and why is it used?

Mohan — Tue, 18 Jul 2023 12:20:36 +0000

Docker is a container management tool.
Docker is used for developing and Deploying distributed applications that can run in different environments without any compatible issues

4. How DevOps and SRE are different? 5. What is DevSecOps?

Mohan — Mon, 17 Jul 2023 08:22:23 +0000

DevOps is a set of practices that aims to shorten the software development lifecycle and speed the delivery of higher-quality software by breaking down the silos and combining and automating the work of software development teams and IT operations teams.

Site Reliability Engineering (SRE) uses software engineering to automate IT operations tasks that would normally be performed by system administrators. These tasks include production system management, change management and incident response.

Development and implementation
DevOps is about core development. SRE is about implementing the core. What does that mean? Let’s think about it this way.

DevOps teams are focused on core development. They are working on a product or application that is the solution to someone’s problem. They are taking an agile approach to software development that helps them build, test, deploy and monitor applications with speed, quality and control.

SREs are working on the implementation of the core. They are constantly giving feedback back into that core development group to say "Hey, something that you guys have designed isn't working exactly the way that you think that it is." SRE leverages operations data and software engineering to automate IT operations tasks and accelerate software delivery, while minimizing IT risk.

Skills
There are different skill sets between DevOps and SREs. Core development DevOps are the guys that love writing software. They are writing code and testing it and pushing it out into production to get an application line to help solve a problem.

SREs are more investigative. They are willing to do the analysis to find why something has gone wrong. They want to ensure that the same problems don’t keep happening. They want to be proactive in their efforts, not reactive. They want to automate repetitive tasks so they can innovate.

Automation
Sometimes, there just isn’t enough time to do everything manually, regardless of your role. Sometimes you need to find ways to automate things so that you can focus your time and energy on the innovation. You don’t have to automate everything; But, if you are constantly doing the same task over and over, why not use automation to reduce the toil? Automation is key.

DevOps is going to automate deployment. They’re going to automate tasks and features. SRE is going to automate redundancy, and they're going to automate manual tasks that they can turn into programmatic tasks to keep the stack up and running.

DevSecOps—short for development, security, and operations—automates the integration of security at every phase of the software development lifecycle, from initial design through integration, testing, deployment, and software delivery.

DevSecOps represents a natural and necessary evolution in the way development organizations approach security. In the past, security was 'tacked on' to software at the end of the development cycle (almost as an afterthought) by a separate security team and was tested by a separate quality assurance (QA) team.

What are the list of DevOps Tools?

Mohan — Thu, 13 Jul 2023 11:57:45 +0000

GIT,Ansilbe,Docker,Kubernetes,Grafana,Promethues,Jenkins et