Add a Docker Compose tutorial

Adds a Docker Compose tutorial to the website that shows how to start a
Wordpress site and includes information about how to get DNS working.

Fixes #115

PiperOrigin-RevId: 330652842

1 files changed, 100 insertions, 0 deletions

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+# Wordpress with Docker Compose
+
+This page shows you how to deploy a sample [WordPress][wordpress] site using
+[Docker Compose][docker-compose].
+
+### Before you begin
+
+[Follow these instructions][docker-install] to install runsc with Docker. This
+document assumes that Docker and Docker Compose are installed and the runtime
+name chosen for gVisor is `runsc`.
+
+### Configuration
+
+We'll start by creating the `docker-compose.yaml` file to specify our services.
+We will specify two services, a `wordpress` service for the Wordpress Apache
+server, and a `db` service for MySQL. We will configure Wordpress to connect to
+MySQL via the `db` service host name.
+
+> **Note:** Docker Compose uses it's own network by default and allows services
+> to communicate using their service name. Docker Compose does this by setting
+> up a DNS server at IP address 127.0.0.11 and configuring containers to use it
+> via [resolv.conf][resolv.conf]. This IP is not addressable inside a gVisor
+> sandbox so it's important that we set the DNS IP address to the alternative
+> `8.8.8.8` and use a network that allows routing to it. See
+> [Networking in Compose][compose-networking] for more details.
+
+> **Note:** The `runtime` field was removed from services in the 3.x version of
+> the API in versions of docker-compose < 1.27.0. You will need to write your
+> `docker-compose.yaml` file using the 2.x format or use docker-compose >=
+> 1.27.0. See this [issue](https://github.com/docker/compose/issues/6239) for
+> more details.
+
+```yaml
+version: '2.3'
+
+services:
+   db:
+     image: mysql:5.7
+     volumes:
+       - db_data:/var/lib/mysql
+     restart: always
+     environment:
+       MYSQL_ROOT_PASSWORD: somewordpress
+       MYSQL_DATABASE: wordpress
+       MYSQL_USER: wordpress
+       MYSQL_PASSWORD: wordpress
+     # All services must be on the same network to communicate.
+     network_mode: "bridge"
+
+   wordpress:
+     depends_on:
+       - db
+     # When using the "bridge" network specify links.
+     links:
+       - db
+     image: wordpress:latest
+     ports:
+       - "8080:80"
+     restart: always
+     environment:
+       WORDPRESS_DB_HOST: db:3306
+       WORDPRESS_DB_USER: wordpress
+       WORDPRESS_DB_PASSWORD: wordpress
+       WORDPRESS_DB_NAME: wordpress
+     # Specify the dns address if needed.
+     dns:
+       - 8.8.8.8
+     # All services must be on the same network to communicate.
+     network_mode: "bridge"
+     # Specify the runtime used by Docker. Must be set up in
+     #  /etc/docker/daemon.json.
+     runtime: "runsc"
+
+volumes:
+    db_data: {}
+```
+
+Once you have a `docker-compose.yaml` in the current directory you can start the
+containers:
+
+```bash
+docker-compose up
+```
+
+Once the containers have started you can access wordpress at
+http://localhost:8080.
+
+Congrats! You now how a working wordpress site up and running using Docker
+Compose.
+
+### What's next
+
+Learn how to deploy [WordPress with Kubernetes][wordpress-k8s].
+
+[docker-compose]: https://docs.docker.com/compose/
+[docker-install]: ../quick_start/docker.md
+[wordpress]: https://wordpress.com/
+[resolv.conf]: https://man7.org/linux/man-pages/man5/resolv.conf.5.html
+[wordpress-k8s]: kubernetes.md
+[compose-networking]: https://docs.docker.com/compose/networking/