Docker Basic Commands ~ Data Integration / DevOps / DataOps Notes

Docker Basic Commands

1. Launching a container :

docker run <image-name>

e.g docker run ubuntu

2. Checking the list of docker containers:

For running containers : docker ps

For running & shutdown list : docker ps -a

3. Stopping the docker container (below command just stops the container it doesn't have files created by container )

docker stop <container id / container_name >

e.g docker stop 0uy1212121d19839121

4. Removing the stopped container

docker rm <container id / container_name >

e.g docker rm smart_world

Note: Its possible to stop multiple containers at the same time either by container ids / container name. While using container id, it is not necessary to specify the enter id , its enough to specify 3/4 characters of container id

docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
fa7d61b970f0 ubuntu "sleep 20" 11 minutes ago Exited (0) 11 minutes ago peaceful_boyd
aa45e8d98ee9 ubuntu "/bin/bash" 12 minutes ago Exited (0) 12 minutes ago friendly_engelbart

$ docker rm fa7 aa4
fa7
aa4

$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES

5. Removing the docker image

docker rmi <image name >

6. Downloading Image

docker pull <image name >

7. Launching the container based on the download the image

docker exec <image name>

8. Append (Detach / Attach )

To run in background :

docker run -d <image name> additional command ifany

e.g docker run -d centos sleep 200

To bring the container to foregroung

docker attach <conatiner-id>

9. Accessing the bash of container interactively

docker run -it <image-id> bash

e.g docker run -it ubuntu bash

Things to remember:

Port Mapping:

By default , containers get launched with network layer. Applications installed in the container can be accessible by two methods.

1. IP address of the container and by this way. only docker host can access the applications .

2. IP address of the docker host . This is possible by only if port mapping parameter is mentioned while launching the container
docker run -p <dockerhost-portnumber>:<dockerapplication-portnumber> <image-id>
e.g docker run -p 8090:8080 jenkins

Volume Mapping:

By default , data stored in containers are available only when it is running. ie. if a container is stopped , all the data stored will get deleted. In order to persist the storage of container applications and its required to specify the volume mapping parameter when launching the container.

docker run -v <location of docker host>:<location of container> <image id>

e.g docker run -p 3306:3306 -v /opt/mysqldata:/var/mysql mysql

docker file and build is used to create custom docker image as per the requirements.

Note: docker file should always begin with os related image .

sample docker file