====== Docker quick ======

===== - Volumes =====
  * show https://stackoverflow.com/questions/30133664/how-do-you-list-volumes-in-docker-containers


===== - Run container =====
==== - Host network ====
Create and start the container as a detached process. 
The --rm option means to remove the container once it exits/stops. 
The -d flag means to start the container detached (in the background).
Host network --network host, bind container port to host port.

    docker run --rm -d --network host --name my_nginx nginx

==== - Run docker with custom entrypoint ====
Example docker file: https://github.com/yibo-cai/compass-db/raw/arm64/Dockerfile

We want to override the default entrypoint which starts mysql as CMD. First, start the image:
    docker run --entrypoint /sbin/entrypoint.sh  -it opnfv/compass-db
==== - Attach to the running image ====
Not using attach b/c it allows only one tty, so:

    docker ps -a
    CONTAINER ID        IMAGE                 COMMAND                  CREATED             STATUS         PORTS     NAMES
    002af509471f        opnfv/compass-db      "/sbin/entrypoint.sh"    2 minutes ago       Up 2 minutes   3306/tcp  condescending_bartik

    docker exec -it -u root 002af509471f /bin/bash

==== - See concole log ====
    sudo docker logs e537fb5d99f7
    
**Note:**
  * entrypoint arguments come after image name: docker run --entrypoint "/bin/ls" debian -al /root
  * Entrypoint vs CMD: https://medium.freecodecamp.org/docker-entrypoint-cmd-dockerfile-best-practices-abc591c30e21
  * Docker start script: https://forums.docker.com/t/best-practice-to-run-a-bash-setup-script-after-creation-of-container/28988
  * mysql entrypoint: https://stackoverflow.com/questions/25920029/setting-up-mysql-and-importing-dump-within-dockerfile
===== - Remove unuse containers =====
  * https://linuxize.com/post/how-to-remove-docker-images-containers-volumes-and-networks/

Remove everything
    docker system prune
    docker container ls -a
    docker container rm cc3f2ff51cab cd20b396a061
    
    docker rm -v $(docker ps -a -q -f status=exited)
    docker rmi $(docker images -f "dangling=true" -q)
    docker volume rm $(docker volume ls -qf dangling=true)
    docker-compose -f docker-compose.yml rm
===== - Build docker =====
Build (.) is context folder, can also be git url:

    docker build -f path/to/Dockerfile . 

Build and tag
    docker build -t whenry/fedora-jboss:latest -t whenry/fedora-jboss:v2.1 .    
====== - Docker-compose ======
    cd dir/to/docker-compose.yml
    docker-compose up
    docker-compose down
    
===== - Environment variables =====
**.env and environment are two things**

  * .env. The docker-compose command will look for a file named .env in the directory you run the command. The docker-compose.yml can use variable defined in the .env file e.g., ${KEY}. The file must be named .env. 
  * Passing environment variables to **docker container** is possible with the top-level 'environment:', 'env-file:' in service definition or --env-file in command line. By passing a file as an argument, you can store it anywhere and name it appropriately using the --env-file option:

    docker-compose --env-file ./config/.env.dev up
    
.env file format:

<code>
# MongoDB variables    
MONGO_DB_PORT=27017    
MONGO_DB_HOST_PORT=30017    
MONGO_DB_VERSION=3.6    
    
# Mosquitto    
MOSQUITTO_USERNAME=mqtt    --> OK
MOSQUITTO_PASSWORD='mqtt'  --> '' included. everything after =  
                           --> IGNORED 
# Kura variables    
ARTEMIS_PORT=1883                       
KURA_PORT=8080 # blah      --> ERROR
</code>

====== - Cheat sheet ======
  * cheatsheet: https://gist.github.com/tedivm/a4ec30066890e43982d888eab1ff8632

## Build docker image

```
$ cd /path/to/Dockerfile
$ sudo docker build .
```

View running processes

```
$ sudo docker ps
```

View all processes

```
$ sudo docker ps -a
```

Run an image in a new container daemonized

```
$ sudo docker run -d <image_name>
```

Run an image in interactive mode with the command `/bin/bash`

```
$ sudo docker run -i -t <image_name> /bin/bash
```

Run an image in interactive mode with the command `/bin/bash` and link the ports.

```
$ sudo docker run -i -t --link <docker_container_name>:<docker_container_alias> <image_name> /bin/bash
```

Run an image with an ENTRYPOINT command in interactive mode with the command `/bin/bash`

```
$ sudo docker run --entrypoint /bin/bash -i -t <image_name>
```

Run an image in interactive mode with the command `/bin/bash` mounting the host director `/var/app/current` to the container directory `/usr/src/app`

```
$ sudo docker run -i -t -v /var/app/current:/usr/src/app/ <image_name> /bin/bash
```

Run an image in interactive mode with the command `/bin/bash` setting the environments variables `FOO` and `BAR`

```
$ sudo docker run -i -t -e FOO=foo -e BAR=bar <image_name> /bin/bash
```