Debug School: Mohit Dubey

List of Git Commands

Mohit Dubey — Fri, 18 Nov 2022 07:28:00 +0000

git init: To initialize a local repository to be tracked by GIT
git clone: to clone the remote repository to local
git pull: to pull the changes remote repository to local(working dir)
** git clean** : Delete a file from git initialized repo
git add: to move the file to the staging area.
git commit: to commit the code to the local repository
git push: to push the code to the remote repository
git stash: to stash the local changes in a temporary folder
git stash pop: to pop the stashed changes
git merge: to merge the changes between two local repos
git fetch: git fetch is a primary command used to download contents from a remote repository
git pull: Git fetch + Git Merge
git cherrypick: to merge the particular change from feature to master branch or any branch
git rm: remove the change or unstage it from local repo
git tag: to tag the latest commit in a local branch
git tag -d : delete the tag
git mv : to move the file or changes between two folders in local repo
git diff : to check the difference between two commits, two commit id need to be passed as arguments
git log: to check the history of commit for a specific branch
git revert: to revert the latest changes or commits from local branch
git status: to check the status of the particular change or file
git config : To set the configuration for your git repo like username , Email

Docker Volume type "tmpfs"

Mohit Dubey — Wed, 16 Nov 2022 05:07:26 +0000

This is another type of docker volume which is stored in the host system’s memory only and not to system’s filesystem.

Once the host system restarts the volume & data is lost

What is a docker image ?

Mohit Dubey — Tue, 15 Nov 2022 06:43:56 +0000

Docker Image is a software package that contains everything to run an application.
Docker image has multiple filesystems called Layers .
Layers are stacked one over the other.
Every layer has a parent layer.
First layer is known as the base image .
Every layer has a merged & diff directory.
Merge directory is something that is attached for the user .
Every layer has a different SHA value .
If you stop the container the merge directory goes away.

Docker Wait

Mohit Dubey — Tue, 15 Nov 2022 05:02:04 +0000

This command is used to wait or block until the one or more container exits and then it outputs their exit codes . If you use docker wait command on a terminal then you cannot use that terminal for running any other commands.

What is Docker Update ?

Mohit Dubey — Tue, 15 Nov 2022 04:55:57 +0000

Docker update command updates the configuration of your container on a fly . For example if your container is using a certain amount of CPU shares you can increase the value of that configuration using docker update without getting into the container.

Docker Stop vs Docker Kill

Mohit Dubey — Mon, 14 Nov 2022 10:00:00 +0000

Although the use case is same for both the commands to terminate the docker containers but when you run docker stop it sends the SIGTERM signal where as it sends SIGKILL signal for docker kill.

Docker pause vs unpause

Mohit Dubey — Mon, 14 Nov 2022 09:55:38 +0000

Docker Pause command halts the running processes inside the container & unpause reinstate the processes .

Use case is just to run the process at a later date & time .

Day1 : DevOps Training (Docker & GIT)

Mohit Dubey — Mon, 14 Nov 2022 07:14:55 +0000

Write a notes on following with your learning with last session

What is Docker?

Docker is a container management platform . It gives you the capability of running your applications in an isolated environment

Why Docker?

Docker was required to overcome the restriction of a PC model where you can create multiple users but can run the application only once due to single PID & network (port)

What is Container

Container is an isolated unit that uses host resources by leveraging the kernel with it's own mount , network & Process ID .

Docker workflow

DockerRegistry(Hub)----> Docker pull (Image is pulled)---> Daemon talks to kernel ----> Docker run (Starts the application)

How container created?

Docker daemon talks to the kernel and asks to create a linux namespace with an isolated network , Mount & runtime environment by leveraging the host resources.