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Docker Frequently Used Commands#

General#

  • docker - show commands & management commands
  • docker version - show docker version
  • docker info - show info like number of containers, etc

Purging All Unused or Dangling Images, Containers, Volumes, and Networks#

  • Docker provides a single command that will clean up any resources — images, containers, volumes, and networks — that are dangling (not associated with a container): 
    docker system prune
  • To additionally remove any stopped containers and all unused images (not just dangling images), add the -a flag to the command: 
    docker system prune -a

Resolve potential IP Conflicts caused by Docker#

Reference: How To Change The Default Docker Subnet

Docker uses the default 172.17.0.0/16 subnet for container networking. If this subnet is not available for docker in your environment (for example because your network already uses this subnet), you must configure Docker to use a different subnet.

Working with Docker Images#

List local images#

  • docker images - list all images
  • docker images -f dangling=true - list all dangling images (-f for filter)

Remove image(s)#

  • docker image rm - remove one or more images from local
  • docker image prune - remove all unused (dangling) images

Re-tag an image#

docker image tag [image:tag(current)] [image:tag(new)]

Build an image from current working directory#

docker build -t [username/repo-name:tag] .

Push an image to Docker Hub Repository#

docker login
docker push [image]

Working with Docker Container#

List containers#

  • docker ps - list running containers
  • docker ps -a - list all containers, -a for all
  • docker ps -a -f status=exited - list all exited containers, -f for filter

Stop containers#

  • Stop a container 
    docker container stop [ID]
  • Stop all running containers 
    docker stop $(docker ps -aq)

Remove all exited containers#

  • Remove a exited container 
    docker rm [ID]
  • Remove all exited containers 
    docker rm $(docker ps -a -f status=exited -q)
    • -q returns the ids of the containers

Run a new container#

docker run [OPTIONS] IMAGE [COMMAND] [ARG...]
  • Create an run a container in foreground 
    docker container run -it -p 80:80 --name nginx-server nginx
  • Create an run a container in background 
    docker container run -d -p 80:80 --name nginx-server nginx
  • Run an fresh ubuntu container interactively and destroy on exit 
    docker run -it --rm ubuntu bash

WHAT RUN DID

  • Looked for image called nginx in image cache
  • If not found in cache, it looks to the default image repo on Docker Hub
  • Pulled it down (latest version), stored in the image cache
  • Started it in a new container
  • We specified to take port 80- on the host and forward to port 80 on the container
  • We could do "$ docker container run --publish 8000:80 --detach nginx" to use port 8000

Run the bash shell in a container interactively#

docker exec -it [CONTAINER NAME] bash

Get logs (Use name or ID)#

docker container logs [NAME]

List processes running in container#

docker container top [NAME]

View info on container#

docker container inspect [NAME]

Specific property (--format)#

docker container inspect --format '{{ .NetworkSettings.IPAddress }}' [NAME]

Performance stats (cpu, mem, network, disk, etc)#

docker container stats [NAME]

Below To Be cleaned up

Some sample container creation#

NGINX:

$ docker container run -d -p 80:80 --name nginx nginx (-p 80:80 is optional as it runs on 80 by default)

APACHE:

$ docker container run -d -p 8080:80 --name apache httpd

MONGODB:

$ docker container run -d -p 27017:27017 --name mongo mongo

MYSQL:

$ docker container run -d -p 3306:3306 --name mysql --env MYSQL_ROOT_PASSWORD=123456 mysql

Create new nginx container and bash into#

$ docker container run -it --name [NAME] nginx bash
  • i = interactive Keep STDIN open if not attached
  • t = tty - Open prompt

For Git Bash, use "winpty"

$ winpty docker container run -it --name [NAME] nginx bash

Access an already created container, start with -ai#

$ docker container start -ai ubuntu

Use exec to edit config, etc#

$ docker container exec -it mysql bash

Alpine is a very small Linux distro good for docker#

$ docker container run -it alpine sh

(use sh because it does not include bash) (alpine uses apk for its package manager - can install bash if you want)

NETWORKING#

"bridge" or "docker0" is the default network#

Get port#

$ docker container port [NAME]

List networks#

$ docker network ls

Inspect network#

$ docker network inspect [NETWORK_NAME]
("bridge" is default)

Create network#

$ docker network create [NETWORK_NAME]

Create container on network#

$ docker container run -d --name [NAME] --network [NETWORK_NAME] nginx

Connect existing container to network#

$ docker network connect [NETWORK_NAME] [CONTAINER_NAME]

Disconnect container from network#

$ docker network disconnect [NETWORK_NAME] [CONTAINER_NAME]

Detach network from container#

$ docker network disconnect