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 Volumes
Creating a Volume
You can create a volume explicitly using the docker volume create command:
docker volume create my-volume
This creates a new volume named my-volume that Docker will manage.
Running a Container with a Volume
When running a container, you can mount the volume using the -v or --mount flag:
docker run -d --name my-app -v my-volume:/app myapp:v1
This mounts the my-volume volume to the /app directory inside the container. Any data written to /app will be stored in the my-volume volume on the host.
Inspecting Volume Contents
You can inspect the contents of the volume on the host machine. The exact location depends on your Docker storage driver, but typically it will be under /var/lib/docker/volumes/. For example:
ls /var/lib/docker/volumes/my-volume/_data
This will list the files stored in the volume.
## Persisting Data
If the container crashes or is removed, the data written to the volume will persist on the host. You can then attach the volume to a new container to access the data:
docker run -d --name new-app -v my-volume:/app myapp:v2
The new container will have access to the same data as the previous container.
Sharing Volumes Between Containers
Volumes can be mounted to multiple containers simultaneously. This allows containers to share data:
docker run -d --name app1 -v my-volume:/data app1:v1
docker run -d --name app2 -v my-volume:/data app2:v1
Both app1 and app2 will have read-write access to the /data directory which points to the my-volume volume.
Docker volumes provide a way to persist data outside the container lifecycle. This ensures important data is not lost when containers are removed or crash. Volumes can be shared between multiple containers and their contents can be inspected directly on the host.
Thanks for making it to the very last. Since you read this do consider
leaving some comments.
Also you might find this post useful
Top comments (0)