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wulucxy/Docker Commands, Help & Tips

Created February 8, 2020 11:37
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#docker
Raw
Docker Commands, Help & Tips
# Docker Commands, Help & Tips
### Show commands & management commands
```
$ docker
```
### Docker version info
```
$ docker version
```
### Show info like number of containers, etc
```
$ docker info
```
# WORKING WITH CONTAINERS
### Create an run a container in foreground
```
$ docker container run -it -p 80:80 nginx
```
### Create an run a container in background
```
$ docker container run -d -p 80:80 nginx
```
### Shorthand
```
$ docker container run -d -p 80:80 nginx
```
### Naming Containers
```
$ docker container run -d -p 80:80 --name nginx-server nginx
```
### TIP: WHAT RUN DID
- Looked for image called nginx in image cache
- If not found in cache, it looks to the default image repo on Dockerhub
- 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
- We can specify versions like "nginx:1.09"
### List running containers
```
$ docker container ls
```
OR
```
$ docker ps
```
### List all containers (Even if not running)
```
$ docker container ls -a
```
### Stop container
```
$ docker container stop [ID]
```
### Stop all running containers
```
$ docker stop $(docker ps -aq)
```
### Remove container (Can not remove running containers, must stop first)
```
$ docker container rm [ID]
```
### To remove a running container use force(-f)
```
$ docker container rm -f [ID]
```
### Remove multiple containers
```
$ docker container rm [ID] [ID] [ID]
```
### Remove all containers
```
$ docker rm $(docker ps -aq)
```
### Get logs (Use name or ID)
```
$ docker container logs [NAME]
```
### List processes running in container
```
$ docker container top [NAME]
```
#### TIP: ABOUT CONTAINERS
Docker containers are often compared to virtual machines but they are actually just processes running on your host os. In Windows/Mac, Docker runs in a mini-VM so to see the processes youll need to connect directly to that. On Linux however you can run "ps aux" and see the processes directly
# IMAGE COMMANDS
### List the images we have pulled
```
$ docker image ls
```
### We can also just pull down images
```
$ docker pull [IMAGE]
```
### Remove image
```
$ docker image rm [IMAGE]
```
### Remove all images
```
$ docker rmi $(docker images -a -q)
```
#### TIP: ABOUT IMAGES
- Images are app bianaries and dependencies with meta data about the image data and how to run the image
- Images are no a complete OS. No kernel, kernel modules (drivers)
- Host provides the kernel, big difference between VM
### 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
```
## CONTAINER INFO
### 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
### 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
```
### Run/Create Ubuntu container
```
$ docker container run -it --name ubuntu ubuntu
```
**(no bash because ubuntu uses bash by default)**
### 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
```
$ 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
```
# IMAGE TAGGING & PUSHING TO DOCKERHUB
# tags are labels that point ot an image ID
```
$ docker image ls
```
Youll see that each image has a tag
### Retag existing image
```
$ docker image tag nginx btraversy/nginx
```
### Upload to dockerhub
```
$ docker image push bradtraversy/nginx
```
### If denied, do
```
$ docker login
```
### Add tag to new image
```
$ docker image tag bradtraversy/nginx bradtraversy/nginx:testing
```
### DOCKERFILE PARTS
- FROM - The os used. Common is alpine, debian, ubuntu
- ENV - Environment variables
- RUN - Run commands/shell scripts, etc
- EXPOSE - Ports to expose
- CMD - Final command run when you launch a new container from image
- WORKDIR - Sets working directory (also could use 'RUN cd /some/path')
- COPY # Copies files from host to container
### Build image from dockerfile (reponame can be whatever)
### From the same directory as Dockerfile
```
$ docker image build -t [REPONAME] .
```
#### TIP: CACHE & ORDER
- If you re-run the build, it will be quick because everythging is cached.
- If you change one line and re-run, that line and everything after will not be cached
- Keep things that change the most toward the bottom of the Dockerfile
# EXTENDING DOCKERFILE
### Custom Dockerfile for html paqge with nginx
```
FROM nginx:latest # Extends nginx so everything included in that image is included here
WORKDIR /usr/share/nginx/html
COPY index.html index.html
```
### 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
```
$ docker volume ls
```
### Cleanup unused volumes
```
$ docker volume prune
```
### Pull down mysql image to test
```
$ docker pull mysql
```
### Inspect and see volume
```
$ docker image inspect mysql
```
### Run container
```
$ docker container run -d --name mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=True mysql
```
### Inspect and see volume in container
```
$ 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
```
$ 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)
```
$ docker container run -d --name mysql -e MYSQL_ALLOW_EMPTY_PASSWORD=True -v mysql-db:/var/lib/mysql mysql
```
### Inspect new named volume
```
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)
```
$ docker container run -p 80:80 -v $(pwd):/usr/share/nginx/html nginx
```
### Go into the container and check
```
$ 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
```
$ touch test.txt
```
# 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)
```
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'
```
### To run
```
docker-compose up
```
### You can run in background with
```
docker-compose up -d
```
### To cleanup
```
docker-compose down
```
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