Docker

Use Docker without sudo

For this, we need to add the user to the docker mod.

Below is the terminal command:

sudo usermod -a -G docker userName
#or
sudo usermod -a -G docker $USER

Now we need to logout and login again to see effects.

Pull and run a public docker image from the docker hub.

Here’s the command

version is optional

docker run image:version

Docker advantages

1 Its light

2 Its fast

3 It allows to have different configuration layer

i.e. We can separate it form the actual OS configs.

4 We also get the benefit of running the same image

with different versions simultaneously on the same computer.

Basic Commands

docker pull imageName:version

This gets the public image from docker hub.

The version is optional

docker images

It shows the list of all images

REPOSITORY               TAG       IMAGE ID       CREATED         SIZE
redis                    latest    e10bd12f0b2d   7 days ago      138MB

docker run imageName:version

Here things get interesting.

If you mentioned the version while pulling, you must do so now too.

Else docker will pull the latest version of it and then run it.

💡 Well, you can stop it by just doing a Ctrl+C that's it.

docker ps

lists down all the currently running images.

💡 We can also use Ctrl+C to stop the image

docker run -d imageName

To run the image in detached mode i.e. now Ctrl+C won’t work on it.

It runs in detached mode

example

docker run -d -p3000:3000 --name node-app example-node

Now to stop a detached image

We need to

💡 docker ps
Now we have the id
We can stop it simply using
docker stop id

docker ps -a

This prints the whole history.

From here we can start a container with its id.

by using the command

docker start id

docker run -p:containerPort image:version

Now the command above looks a bit big.

Let me break it down.

Let’s first have an example

docker run -p9000:6379 -d redis

Result

docker ps
CONTAINER ID   IMAGE     COMMAND                  CREATED          STATUS          PORTS                                       NAMES
5aeaf8ee3849   redis     "docker-entrypoint.s…"   14 seconds ago   Up 11 seconds   0.0.0.0:9000->6379/tcp, :::9000->6379/tcp   xenodochial_curran

This helps us bind a host port to the container port.

This is really helpful when we want to run 2 versions of the same image.

We can bind them to 2 different ports.

docker logs id

This helps us see the logs of a container.

This helps us solve bugs and errors.

💡 we can also use names instead of id here

Naming the docker containers

docker run —name custom-name image:version

docker run -p9000:6379 -d --name redis_latest redis
docker run -d -p9001:6379 --name redis_old redis:6.2

docker rm container_id_or_name

This command removes the container

ex

docker rm redis_old redis_latest

Remove all containers

💡

docker ps -q | xargs docker stop
docker ps -q | xargs docker rm

To get the interactive terminal of a container

docker exec -it container_id_or_name /bin/bash

To exit the terminal simply Enter exit

Here -it stands for interactive mode.

Docker Volume

Think of them as special folders that you can use to store data outside of your container. This is really helpful because it means that even if your container gets deleted or crashes, your data will still be safe and sound.

Example

docker run -p 27017:27017 -v atulDB:/data/db --name my-mongodb-container mongo:latest