+++
date="2023-02-09"
author="spanskiduh"
title="docker"
description="click to read about docker"
+++
# Docker

## Nuke docker
```bash

#!/bin/bash

printf "Stopping all containers\n"
docker ps | awk ' {print $1} ' | xargs docker kill

printf "Deleting all containers\n"
docker container ls --filter "status=exited" | awk '{ print $1 }' | xargs docker container rm

printf "Deleting all images\n"
docker image ls | awk '{print $3}' | xargs docker image rm --force
```

## Basic config example
 
```yml
# docker-compose.yml
version: '3'
 
services:
  web:
    build: .
    # build from Dockerfile
    context: ./Path
    dockerfile: Dockerfile
    ports:
     - "5000:5000"
    volumes:
     - .:/code
  redis:
    image: redis
```
 
## Common commands
 
```bash
# Starts existing containers for a service.
docker-compose start
 
# Stops running containers without removing them.
docker-compose stop
 
# Pauses running containers of a service.
docker-compose pause
 
# Unpauses paused containers of a service.
docker-compose unpause
 
# Lists containers.
docker-compose ps
 
# Builds, (re)creates, starts, and attaches to containers for a service.
docker-compose up
 
# Stops containers and removes containers, networks, volumes, and images created by up.
docker-compose down
```
 
## Config file reference
 
### Building
 
```yml
web:
  # build from Dockerfile
  build: .
  # build from custom Dockerfile
  build:
    context: ./dir
    dockerfile: Dockerfile.dev
  # build from image
  image: ubuntu
  image: ubuntu:14.04
  image: tutum/influxdb
  image: example-registry:4000/postgresql
  image: a4bc65fd
```
 
### Ports
 
```yml
ports:
  - "3000"
  - "8000:80"  # guest:host
# expose ports to linked services (not to host)
expose: ["3000"]
```
 
### Commands
 
```yml
# command to execute
command: bundle exec thin -p 3000
command: [bundle, exec, thin, -p, 3000]
 
# override the entrypoint
entrypoint: /app/start.sh
entrypoint: [php, -d, vendor/bin/phpunit]
```
 
### Environment variables
 
```yml
# environment vars
environment:
  RACK_ENV: development
environment:
  - RACK_ENV=development
 
# environment vars from file
env_file: .env
env_file: [.env, .development.env]
```
 
### Dependencies
 
```yml
# makes the `db` service available as the hostname `database`
# (implies depends_on)
links:
  - db:database
  - redis
 
# make sure `db` is alive before starting
depends_on:
  - db
```
 
### Other options
 
```yml
# make this service extend another
extends:
  file: common.yml  # optional
  service: webapp
volumes:
  - /var/lib/mysql
  - ./_data:/var/lib/mysql
```
 
## Advanced features
 
### Labels
 
```yml
services:
  web:
    labels:
      com.example.description: "Accounting web app"
```
 
### DNS servers
 
```yml
services:
  web:
    dns: 8.8.8.8
    dns:
      - 8.8.8.8
      - 8.8.4.4
```
 
### Devices
 
```yml
services:
  web:
    devices:
      - "/dev/ttyUSB0:/dev/ttyUSB0"
```
 
### External links
 
```yml
services:
  web:
    external_links:
      - redis_1
      - project_db_1:mysql
```
 
### Hosts
 
```yml
services:
  web:
    extra_hosts:
      - "somehost:192.168.1.100"
```
 
### Network
 
```yml
# creates a custom network called `frontend`
networks:
  frontend:
```
 
### External network
 
```yml
# join a preexisting network
networks:
  default:
    external:
      name: frontend
```

### Problmes with UFW on VPS?

Well this comes with experience iguess. I once disabled all traffic, but the ssh and https using UFW
,but did not know that docker fucks up iptables and bypasses ufw. So I left
the database open...


So there is thankfully a [workadound](https://github.com/chaifeng/ufw-docker/blob/master/README.md#solving-ufw-and-docker-issues),

basically add this segment to file `/etc/ufw/after.rules`.

```bash
# BEGIN UFW AND DOCKER
*filter
:ufw-user-forward - [0:0]
:ufw-docker-logging-deny - [0:0]
:DOCKER-USER - [0:0]
-A DOCKER-USER -j ufw-user-forward

-A DOCKER-USER -j RETURN -s 10.0.0.0/8
-A DOCKER-USER -j RETURN -s 172.16.0.0/12
-A DOCKER-USER -j RETURN -s 192.168.0.0/16

-A DOCKER-USER -p udp -m udp --sport 53 --dport 1024:65535 -j RETURN

-A DOCKER-USER -j ufw-docker-logging-deny -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -d 192.168.0.0/16
-A DOCKER-USER -j ufw-docker-logging-deny -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -d 10.0.0.0/8
-A DOCKER-USER -j ufw-docker-logging-deny -p tcp -m tcp --tcp-flags FIN,SYN,RST,ACK SYN -d 172.16.0.0/12
-A DOCKER-USER -j ufw-docker-logging-deny -p udp -m udp --dport 0:32767 -d 192.168.0.0/16
-A DOCKER-USER -j ufw-docker-logging-deny -p udp -m udp --dport 0:32767 -d 10.0.0.0/8
-A DOCKER-USER -j ufw-docker-logging-deny -p udp -m udp --dport 0:32767 -d 172.16.0.0/12

-A DOCKER-USER -j RETURN

-A ufw-docker-logging-deny -m limit --limit 3/min --limit-burst 10 -j LOG --log-prefix "[UFW DOCKER BLOCK] "
-A ufw-docker-logging-deny -j DROP

COMMIT
# END UFW AND DOCKER
```


## Best flag for debugging dockerfile
`docker compose --verbose up --build`
But do not fuck up the order of the arguments!