Debug School: B. Tarun Kumar Reddy

Write a Notes on all the git commands which we have learned and one line explaination of it.

B. Tarun Kumar Reddy — Fri, 18 Nov 2022 09:04:45 +0000

git init:- initializes the git in the folder
git config :- used to config the git user name and email associated
git add file1.txt :- Add file1.txt to
git add . :- Adds a file to the staging area.
git commit -m "commit message" :- Records or snapshots the file permanently in the version history.
git branch :- lists all the local branches in the current repository.
git checkout :- This command is used to switch from one branch to another.
git merge :- command merges the specified branch’s history into the current branch.
git clean :- used to remove unwanted files from your working directory
git clone URL:- For getting a repository from an existing URL
git log :- used to list the version history for the current branch
git status :- lists all the files that have to be committed.

Docker Volume type "tmpfs"

B. Tarun Kumar Reddy — Wed, 16 Nov 2022 05:27:10 +0000

How can we store container data in memory using docker volume

tmpfs in Docker is used to store the container data into host's memory. But when the container is stopped or host system is restarted the data written into tmpfs will be lost.

command for attaching tmpfs to container:

docker run -itd --name --mount type=tmpfs,destination=/opt/example ubuntu

Day 2 - Docker Images

B. Tarun Kumar Reddy — Tue, 15 Nov 2022 06:49:24 +0000

What is a Docker image. Explain in 10 points.

-> Docker image is a repository.
-> Docker images are immutable, they can't be changed.
-> Docker images can be duplicated, shared or deleted.
-> Docker images contains the ROOTFS (root file system), USERFS (user file system), APPFS (application file systems for OPENJDK,TOMCAT and CUSTOMAPPS).
-> ROOTFS and USERFS together called as basic layer of an image.
-> Docker image consists of multiple filesystems OR it is a collection of multiple filesystems.
-> File systems are called layers as they are on top of each other in the docker images.
-> Each layer has a unique shad ID.
-> Overlay2 is one of the storage driver used in docker to store docker images.
-> whenever we make changes (like writing file/updating file), that changes will get updated in both merged layer and image layer.

Day 2 Assignment-1

B. Tarun Kumar Reddy — Tue, 15 Nov 2022 04:57:49 +0000

What is use of "docker update" ?

The docker update command updates the container configuration dynamically. This command is used to prevent the containers from use up too many resources from the docker host.

What is the use of "docker wait" ?

docker wait command is used to block or wait until one or more containers stops, and then it shows the exit code as output, that is why we cannot use the terminal if we are running this command on the terminal.

Assignment 2 by Tarun

B. Tarun Kumar Reddy — Mon, 14 Nov 2022 10:17:00 +0000

What is the difference between docker pause and docker unpause?
Hint - docker stats
docker pause - This command suspends all processes in the container which is specified by the user.
docker unpause - the docker unpause command resumes all processes in the container that is specified by the user.

What is the difference between docker stop and docker kill Hints - Return value of linux + SIGNALs

docker stop - docker stop will shutdown one or more running containers. docker stop sends a SIGTERM signal to the main process inside the container
docker kill - docker kill command kills one or more running containers immediately. The main process inside the container sends SIGKILL signal.

Understanding about Docker

B. Tarun Kumar Reddy — Mon, 14 Nov 2022 07:22:48 +0000

Write a notes on following with your learning with last session:

What is Docker?
Docker is a container management platform/tool. In general terms, It is a interface between humans and kernel.

Why Docker?
Docker can be used to save time, save memory and improve the quality of the software and decrease the capital expense by creating different environments on same Kernel

What is Container?
Container can be defined as a running image that contains 1 PID tree, 1 network, 1 Root File System and User Namespace.

Docker workflow
User ---> Client ---> Docker host (Containers + Images) ---> Docker registry(Hub)

How container created?
We can download an image from Docker Registry and the images become Containers when they are running in Docker Engine.