Debug School: Sujatha Sundar

Git Commands:

Sujatha Sundar — Fri, 18 Nov 2022 07:11:03 +0000

git init: To init or create a local repository
git clone: to clone the remote repository to local
git pull: to pull the changes remote repository to local(working dir)
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: to merge the change between two remote branches
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 log --oneline: to check the history in oneline
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 user.name: we can configure the author name and etc. of the particular repo.

How can we store container data in memory using docker volume

Sujatha Sundar — Wed, 16 Nov 2022 05:20:46 +0000

tmpfs : this type of mount is temporary and persists on host memory.it does not allow sharing of mounted data among containers because it's a temporary volume. Once the host restarts the data will be gone.
Use Case: It can be used in the fastest mathematical operations results processing.

Docker Image

Sujatha Sundar — Tue, 15 Nov 2022 06:39:23 +0000

1) It's the layers of file system>
2) All the layers have relationship with each other if you are pulling the top layer the parent layer will be pulled automatically
3) The Layer id will be stored under storage area example /var/lib/docker/overlay2
4) The data layer and file system will be under overlay2
5) the meta data like environment variable will be under images folder
6) When we start a container there is a merge layer will get created, which is the combination of all the layers which we have pulled
7) Even Many images are pulled the layer id will be stored only under overlay2 folder
8) This Images are using sha 256 algorithm.
9) When we add some data into the container and even we stopped the container after that, the data will be available under overlay2 folder as a layer, and it will get attached to the container once is started.
10) We can see the layer information using "df -kh" and also the memory using "du -h --max-dept=1"

Docker Update, Docker Wait

Sujatha Sundar — Tue, 15 Nov 2022 05:18:00 +0000

Docker Update: It's like limiting the resources which were used by the container from the host machine.
Docker wait: this command will exit with return code "0" only if the container stops.

Difference between docker stop and kill

Sujatha Sundar — Mon, 14 Nov 2022 10:05:51 +0000

Both the commands generally stop the process, but docker kill like stopping the container forcefully.

What is Docker? Why Docker? What is Container Docker workflow How container created?

Sujatha Sundar — Mon, 14 Nov 2022 07:05:00 +0000

What is Docker:
Docker is not the name of the product, it's docker engine. It's Basically the container management tool. Kind of the utility to request the kernel to create multiple PID, root file, users etc.

*Why Docker: *
To run the multiple similar application in a single PC we can use dockers which again request kernel for separate resources isolated with each other, Will reduce time, cost and effort of running the application.

What is Container:
Container is basically a bundle of rootfs, pid tree, users, with application on top of it.

Docker Workflow and how container created:
The docker cli will talk to docker client and then docker client will pull the images from registry. Once the images are pulled we can run the images using the commands from docker client.