docker cheat sheet

-

常用命令

Docker Commands, Help & Tips

WORKING WITH CONTAINERS

IMAGE COMMANDS

Some sample container creation

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# 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

CONTAINER INFO

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# 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]

ACCESSING CONTAINERS

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# Create new nginx container and bash into
$ docker container run -it --name [NAME] nginx bash
# For Git Bash, use "winpty"
$ winpty docker container run -it --name [NAME] nginx bash
# Run/Create Ubuntu container (no bash because ubuntu uses bash by default)
$ docker container run -it --name ubuntu ubuntu
# You can also make it so when you exit the container does not stay by using the -rm flag
$ docker container run --rm -it --name [NAME] ubuntu
# 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 (use sh because it does not include bash) (alpine uses apk for its package manager - can install bash if you want)
$ docker container run -it alpine sh

• i = interactive Keep STDIN open if not attached
• t = tty - Open prompt

Limiting The Memory Usage For Containers

In order to limit the amount of memory a docker container process can use, simply set the -m [memory amount] flag with the limit.

To run a container with memory limited to 256 MBs:

Example: docker run -name [name] -m [Memory (int)][memory unit (b, k, m or g)] -d (to run not to attach) -p (to set access and expose ports) [image ID]

• docker run -m 64m -d -p 8082:80 tutum/wordpress

NETWORKING

“bridge” or “docker0” is the default network

IMAGE TAGGING & PUSHING TO DOCKERHUB

DOCKERFILE PARTS

demo

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FROM nginx:latest # Extends nginx so everything included in that image is included here
WORKDIR /usr/share/nginx/html
COPY index.html index.html

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# Build image from Dockerfile
$ docker image build -t nginx-website
# Running it
$ docker container run -p 80:80 --rm nginx-website
# Tag and push to Dockerhub
$ docker image tag nginx-website:latest btraversy/nginx-website:latest
$ docker image push bradtraversy/nginx-website

VOLUMES

Volume - Makes special location outside of container UFS. Used for databases

Bind Mount -Link container path to host path

Check volumes

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\$ docker volume ls

Cleanup unused volumes

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\$ docker volume prune

Pull down mysql image to test

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\$ docker pull mysql

Inspect and see volume

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\$ docker image inspect mysql

Run container

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\$ docker container run -d --name mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=True mysql

Inspect and see volume in container

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\$ docker container inspect mysql

TIP: Mounts

• You will also see the volume under mounts
• Container gets its own uniqe location on the host to store that data
• Source: xxx is where it lives on the host

Check volumes

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\$ docker volume ls

There is no way to tell volumes apart for instance with 2 mysql containers, so we used named volumes

Named volumes (Add -v command)(the name here is mysql-db which could be anything)

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\$ docker container run -d --name mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=True -v mysql-db:/var/lib/mysql mysql

Inspect new named volume

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docker volume inspect mysql-db

BIND MOUNTS

• Can not use in Dockerfile, specified at run time (uses -v as well)
• … run -v /Users/brad/stuff:/path/container (mac/linux)
• … run -v //c/Users/brad/stuff:/path/container (windows)

TIP: Instead of typing out local path, for working directory use $(pwd):/path/container - On windows may not work unless you are in your users folder

Run and be able to edit index.html file (local dir should have the Dockerfile and the index.html)

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$ docker container run  -p 80:80 -v $(pwd):/usr/share/nginx/html nginx

Go into the container and check

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$ docker container exec -it nginx bash
$ cd /usr/share/nginx/html
$ ls -al

You could create a file in the container and it will exiost on the host as well

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$ touch test.txt

Link

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$ docker run -d --name my-postgres postgres

now Link it with dot net

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$ docker run -d -p 5000:5000 --link my-postgres:postgres btree/dotnet

DOCKER COMPOSE

• Configure relationships between containers
• Save our docker container run settings in easy to read file
• 2 Parts: YAML File (docker.compose.yml) + CLI tool (docker-compose)

1. docker.compose.yml - Describes solutions for

• containers
• networks
• volumes

2. docker-compose CLI - used for local dev/test automation with YAML files

Sample compose file (From Bret Fishers course)

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version: '2'

# same as
# docker run -p 80:4000 -v $(pwd):/site bretfisher/jekyll-serve

services:
  jekyll:
    image: bretfisher/jekyll-serve
    volumes:
      - .:/site
    ports:
      - '80:4000'

Example 2

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version: '3'
services:
  app:
    container_name: docker-node-mongo
    restart: always
    build: .
    ports:
      - '80:3000'
    links:
      - mongo
  mongo:
    container_name: mongo
    image: mongo
    ports:
      - '27017:27017'

To run

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docker-compose up

You can run in background with

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docker-compose up -d

To cleanup

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docker-compose down

this has been taken from