Play With Docker

Install and Run Docker

If error from docker daemon (Server) while starting then run usermod -aG docker <user> - On Linux adds to local docker Unix group. Once added will need to sign out of shell then back in

Test docker is running

$ docker version

Should see a response from both Client: and Server:

View docker images

$ docker image ls

Run a filter i.e. show only images tagged as latest

$ docker image ls --filter=reference="*:latest"

Search for images on Docker Hub

$ docker search alpine

Filter for official images

$ docker search alpine --filter "is-official=true"

Inspect a docker image

$ docker image inspect ubuntu:latest

Remove a docker image

$ docker image rm alpine:latest

Delete all docker images

$ docker image rm $(docker image ls -q) -f

Pull a docker image

$ docker image pull ubuntu:latest

Pull unofficial images

$ docker image pull <username>/<image>:<tag>

Pull from a registery other than Docker Hub

i.e. Google Container Registry (GCR - gcr.io)

$ docker image pull gcr.io/USERNAME/image:latest

Spin up a quick container

$ docker container run -it ubuntu:latest /bin/bash

$ docker container run --name ctrl -it alpine:latest sh

The -it flag attaches current shell to terminal of the container. To exit this container without terminating it - press Ctrl-PQ

View docker containers

$ docker container ls

Connect to a docker container

$ docker container exec -it CONTAINER <name>|<id> bash

Stop a docker container

$ docker container stop CONTAINER <name>|<id>

Remove a docker container

$ docker container rm CONTAINER <name>|<id>

Remove all docker containers

$ docker container rm $(docker container ls -aq) -f

Docker container restart policies

• always
• unless-stopped
• on-failed

$ docker container run --name <name> -it --restart always

Note: —restart always vs. —restart unless-stopped. unless-stopped will not restart when the daemon restarts if they were initially stopped. —restart always will.

Run docker container as a background process

$ docker container run -d --name <name> -p 80:8080\ <repo-name>|<image>

-d stands for daemon mode and -p sets ports as host:container. localhost:80 is mapped to 8080 inside the container

Simple Dockerfile for basic Node.js app

FROM alpine
RUN apk add --update nodejs nodejs-npm
COPY . /src
WORKDIR /src
RUN npm install
EXPOSE 8080
ENTRYPOINT ["node", "./app.js"]

Build a docker image from a Dockerfile

$ docker image build -t test:latest

Run a docker container from a docker image

$ docker container run -d --name web1 --publish 8080:8080 test:latest

No Space left on device

$ rm -rf  ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2