Docker-compose

Docker Compose

• A tool to run multiple containers

• Insllation: apt install docker-compose

Commands:

• docker-compose up [-d] [--build]

• docker-compose down

• docker-compose restart

Example of docker-compose.yml

• Running 1 nginx proxy named management, 1 oxidized and 1 backupmgmt

version: '3'

services:
    management:
        image: nginx
        container_name: management
        ports:
            - 10.10.10.1:80:80
            - 10.10.10.1:443:443
        volumes:
            - /etc/nginx:/etc/nginx/conf.d/
            - /storage:/storage
            - /etc/localtime:/etc/localtime:ro
        restart: always
        extra_hosts:
        - "host.docker.internal:host-gateway"

    oxidized:
        depends_on:
            - management
        image: oxidized:latest
        container_name: oxidized
        expose:
            - "8888"
        volumes:
            - /etc/oxidized:/root/.config/oxidized
            - /etc/localtime:/etc/localtime:ro
        restart: always
        command: /root/.config/oxidized/startup.sh

    backupmgmt:
        depends_on:
            - management
        image: gunicorn
        container_name: backupmgmt
        expose:
            - "80"
        volumes:
            - /storage/backupmanagement:/app
            - /storage/backup:/storage/backup
        command: /app/gunicorn.sh

Some Errors

nginx: [emerg] host not found in upstream “host.docker.internal:8888” in /etc/nginx/conf.d/nginx.conf:3

• nginx container is configured as a proxy for a another container named oxidizedcontainer

Configuration of NGINX:

upstream oxidizedcontainer{
	server host.docker.internal:8888;
}

server {
	listen 443  ssl;
	server_name	host.domain.com;
	ssl_certificate /etc/nginx/conf.d/bundle.crt;
	ssl_certificate_key /etc/nginx/conf.d/private.key;
	location / {
        	proxy_pass http://oxidizedcontainer/;
		auth_basic "Oxidized";
		auth_basic_user_file /etc/nginx/conf.d/.htpasswd;
		proxy_set_header Host $http_host;
        	}
		access_log /etc/nginx/conf.d/access.log main;
	}

• Reason: docker can’t find host defined in upstream

Solution 1: Using extra_hosts: host.docker.internal

• Nginx uses host IP to access upstream. This requires -p : on upstream containers

• External users can access upstream container directly if -p listen on 0.0.0.0 or external IP

version: '3'

services:
    management:
        image: nginx
        container_name: management
        ports:
            - 10.10.10.1:80:80
            - 10.10.10.1:443:443
        volumes:
            - /etc/nginx:/etc/nginx/conf.d/
            - /storage:/storage
            - /etc/localtime:/etc/localtime:ro
        restart: always
        extra_hosts:
        - "host.docker.internal:host-gateway"

Solution 2

• Using docker-compose to run both proxy and oxidizedcontainer

• Using this, oxidized container doesn’t need to be published, just need to be exposed. This is because by default Compose sets up a single network for your app. Each container for a service joins the default network and is both reachable by other containers on that network, and discoverable by them at a hostname identical to the container name.

Configuration of docker-compose.yml

version: '3'

services:
    proxy:
        image: tiangolo/uwsgi-nginx-flask:latest
        container_name: management
        ports:
            - 10.10.10.1:80:80
            - 10.10.10.1:443:443
        volumes:
            - /etc/nginx:/etc/nginx/conf.d/
            - /etc/www:/app
            - /storage:/storage
        restart: always

    oxidized:
        depends_on:
            - management
        image: oxidized:latest
        container_name: oxidized
        expose:
            - "8888"
        volumes:
            - /etc/oxidized:/root/.config/oxidized
            - /etc/localtime:/etc/localtime:ro
        restart: always

Configuration of nginx.conf

• Note: indentation is important

upstream oxidizedcontainer{
	server oxidized:8888;
}

server {
	listen 80;
	server_name	host.domain.com;
	location / {
        	proxy_pass http://oxidizedcontainer;
		auth_basic "Oxidized";
		auth_basic_user_file /etc/nginx/conf.d/.htpasswd;
        	}
		access_log /etc/nginx/conf.d/access.log main;
	}