Additional info on how to get started with compose

general/docker-compose.md

@@ -1,24 +1,88 @@
 # Docker Compose
+## Intro
+Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration. You can follow these instructions to install docker-compose: https://docs.docker.com/compose/install/
 
-Compose is a tool for defining and running multi-container Docker applications. With Compose, you use a YAML file to configure your application’s services. Then, with a single command, you create and start all the services from your configuration.
-
+## Single service
 Here's a basic example for deploying a Linuxserver container with docker-compose:
 
 ```yaml
-version: "2"
+version: "2.1"
 services:
   heimdall:
     image: linuxserver/heimdall
     container_name: heimdall
-    mem_limit: 256m
     volumes:
-      - /opt/appdata/heimdall:/config
+      - /home/user/appdata/heimdall:/config
     environment:
-      - PUID: 1050
-      - PGID: 1050
+      - PUID: 1000
+      - PGID: 1000
+      - TZ=Europe/London
+    ports:
+      - 80:80
+      - 443:443
     restart: unless-stopped
 ```
 
+If you save the above snippet in a file named `docker-compose.yml`, you can simply run `docker-compose up -d` from within the same folder and the heimdall image will be automatically pulled, and a container will be created and started. `up` means bring the services up, and `-d` means do it in the background.
+
+If you want to do it from a different folder or if you named the yaml file differently, ie. `heimdall.yml`, then you can define it in the command with `-f`: `docker-compose up -d -f /path/to/heimdall.yml`
+
+To bring down the services, simply do `docker-compose down` or `docker-compose down -f /path/to/heimdall.yml` and all containers defined by the yml will be stopped and destroyed.
+
+## Multiple Services
+You can have multiple services managed by a single compose yaml. Copy the contents below the `services:` line in any of our readme yaml samples into the same yaml file and the `docker-compose up/down` commands will apply to all services at once.
+
+Let's say you have the following in a yaml file named `docker-compose.yml`:
+```yaml
+version: "2.1"
+services:
+  heimdall:
+    image: linuxserver/heimdall
+    container_name: heimdall
+    volumes:
+      - /home/user/appdata/heimdall:/config
+    environment:
+      - PUID: 1000
+      - PGID: 1000
+      - TZ=Europe/London
+    ports:
+      - 80:80
+      - 443:443
+    restart: unless-stopped
+  nginx:
+    image: linuxserver/nginx
+    container_name: nginx
+    environment:
+      - PUID=1000
+      - PGID=1000
+      - TZ=Europe/London
+    volumes:
+      - /home/user/appdata/nginx:/config
+    ports:
+      - 81:80
+      - 444:443
+    restart: unless-stopped
+  mariadb:
+    image: linuxserver/mariadb
+    container_name: mariadb
+    environment:
+      - PUID=1000
+      - PGID=1000
+      - MYSQL_ROOT_PASSWORD=ROOT_ACCESS_PASSWORD
+      - TZ=Europe/London
+    volumes:
+      - /home/user/appdata/mariadb:/config
+    ports:
+      - 3306:3306
+    restart: unless-stopped
+```
+You now have 3 services defined in there: `heimdall`, `nginx` and `mariadb`. When you do a `docker-compose up -d`, it will first download the images for all three if they don't exist (if they exist, they are not updated) and it will create all three containers and start them. `docker-compose down` will bring all three services down and destroy the containers (persistent data will remain). 
+
+## Updates
+If you want to update the images and recreate the containers with the same vars, it's extremely easy with docker-compose. First we tell it to update all images via `docker-compose pull`. Then we issue `docker-compose up -d` and it will automatically recreate the containers (as necessary) based on the updated images. If a container's image is already the latest and there was no update, it remains untouched.
+
+Similarly, if you edit the contents of the yaml file and re-issue `docker-compose up -d`, only the containers affected by the changes to the yaml file will be recreated, others will be untouched.
+
 Defining the containers running on your server as code is a core tenet of a "Devops" approach to the world. Constructing elaborate `docker run` commands and then forgetting which variables you passed is a thing of the past when using `docker-compose`.
 
 ## Tips & Tricks
@@ -29,7 +93,7 @@ Create the file `~/.bash_aliases` and populate with the following content:
 
 ```bash
 alias dcp='docker-compose -f /opt/docker-compose.yml '
-alias dcpull='docker-compose -f /opt/docker-compose.yml pull --parallel'
+alias dcpull='docker-compose -f /opt/docker-compose.yml pull'
 alias dclogs='docker-compose -f /opt/docker-compose.yml logs -tf --tail="50" '
 alias dtail='docker logs -tf --tail="50" "$@"'
 ```