zrok/docs/guides/docker-share/_reserved_public_share.mdx

## Goal

Proxy a reserved public subdomain to a backend target with Docker.

## How it Works

The Docker Compose project uses your zrok account token to reserve a public subdomain and keep sharing the backend
target.

When the project runs it will:

1. enable a zrok environment unless `/mnt/.zrok/environment.json` exists in the `zrok_env` volume
1. reserve a public subdomain for the service unless `/mnt/.zrok/reserved.json` exists
1. start sharing the target specified in the `.env` configuration file

## Create the Docker Project

1. Make a folder on your computer to use as a Docker Compose project for your zrok public share with a reserved subdomain and switch to the new directory in your terminal.
1. Download [the reserved public share `compose.yml` project file](pathname:///zrok-public-reserved/compose.yml) into the same directory.
1. Copy your zrok account's enable token from the zrok web console to your clipboard and paste it in a file named `.env` in the same folder like this:

  ```bash title=".env"
  ZROK_ENABLE_TOKEN="8UL9-48rN0ua"
  ```

1. Run the Compose project to start sharing the built-in demo web server.

  ```bash
  docker compose up --detach
  ```

1. Get the public share URL from the output of the `zrok-share` service or by peeking in the zrok console where the share will appear in the graph.

  ```bash
  docker compose logs zrok-share
  ```

  ```buttonless title="Output"
  zrok-public-share-1  |  https://w6r1vesearkj.in.zrok.io/
  ```

This concludes the minimum steps to begin sharing the demo web server. Read on to learn how to pivot to sharing any website or web service by leveraging additional zrok backend modes.

## Proxy Any Web Server

The simplest way to share your existing HTTP server is to set `ZROK_TARGET` (e.g. `https://example.com`) in the environment of the `docker compose up` command. When you restart the share will auto-configure for that URL.

```bash title=".env"
ZROK_TARGET="http://example.com:8080"
```

```bash
docker compose down && docker compose up
```

## Require Authentication

You can require a password or an OAuth login with certain email addresses.

## OAuth Email

You can allow specific email addresses or an email domain by setting `ZROK_OAUTH_PROVIDER` to `github` or `google` and `ZROK_SHARE_OPTS` to specify additional command-line options to `zrok reserve public`. Read more about the OAuth features in [this blog post](https://blog.openziti.io/the-zrok-oauth-public-frontend).

```bash title=".env"
ZROK_OAUTH_PROVIDER="github"
ZROK_SHARE_OPTS="--oauth-email-domains @example.com"
```

## Share Something Different

The reserved public share project uses zrok's `caddy` mode. Caddy accepts configuration as a Caddyfile that is mounted into the container ([zrok Caddyfile examples](https://github.com/openziti/zrok/tree/main/etc/caddy)).

1. Create a Caddyfile. This example demonstrates proxying two HTTP servers with a weighted round-robin load balancer.

  ```console title="Caddyfile"
  http:// {
    # zrok requires this bind address template
    bind {{ .ZrokBindAddress }}
    reverse_proxy /* {
      to http://httpbin1:8080 http://httpbin2:8080
      lb_policy weighted_round_robin 3 2
    }
  }
  ```

1. Create a file `compose.override.yml`. This example adds two `httpbin` containers for Caddy load balance, and masks the default Caddyfile with our custom one.

  ```yaml title="compose.override.yml"
  services:
    httpbin1:
      image: mccutchen/go-httpbin  # 8080/tcp
    httpbin2:
      image: mccutchen/go-httpbin  # 8080/tcp
    zrok-share:
      volumes:
        - ./Caddyfile:/mnt/.zrok/Caddyfile
  ```

1. Re-run the project to load the new configuration.

  ```bash
  docker compose up --force-recreate --detach
  ```

1. Recall the reserved share URL from the log.

  ```bash
  docker compose logs zrok-share
  ```

  ```buttonless title="Output"
  INFO: zrok public URL: https://88s803f2qvao.in.zrok.io/
  ```