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Docker Containers

 

Containers are Docker images that can be run using the Docker run command. Docker’s basic purpose is to run containers.

Setting up a container

You run containers with Docker run. To run a container interactively, launch the Docker container first.

$ sudo docker run –itd centos /bin/bash 
  • Press Ctrl+d or exit will take you back to your OS shell.

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On the Ubuntu server, you will be running CentOS.

Container listing

Using the docker ps command, you can list all the containers running on the machine.

$ docker ps

Syntax

$ docker ps 

Return Value

You’ll see a list of the containers that are running right now.

Example

$ docker ps

Output

As a result of the above command:

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Here’s some more docker ps variations.

$ docker ps -a

Lists all the containers on the system with this command

Syntax

$ docker ps -a 

Options

  • ─a − This tells the docker ps command to list all the containers.

Return Value

All containers will be displayed in the output.

Example

$ sudo docker ps -a 

Output

As a result of the above command:

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docker history

Using this command, you can see all the commands run with an image.

Syntax

$ docker history ImageID 

Options

  • ImageID − The image ID you want to see all the commands run on.

Return Value

All commands run against that image will appear in the output.

Example

$ sudo docker history centos

It’ll show all the commands that were run against the centos  image.

Output

As a result of the above command:

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