add FAQ: Running an offline coop-cloud server

docs/operators/handbook.md

@@ -228,3 +228,23 @@ If you want to teach `abra` how to support your favourite server hosting provide
 `abra` supports creating, listing and removing DNS entries if the 3rd party integration supports it.
 
 If you want to teach `abra` how to support your favourite server hosting provider, we'd glady accept patches.
+
+## Running an offline coop-cloud server 
+
+You may want to run a coop-cloud directly on your device (or in a VM or machine on your LAN), whether that's for testing a recipe or to run coop-cloud apps outside of the cloud ;-)
+In that case you might simply add some names to `/etc/hosts` (e.g `127.0.0.1 myapp.localhost`), or configure them on a local DNS server - which means `traefik` won't be able to use `letsencrypt` to generate and verify SSL certificates. Here's what you can do instead:
+1. In your traefik .env file, edit/uncomment the following lines:
+```
+LETS_ENCRYPT_ENV=staging
+WILDCARDS_ENABLED=1
+SECRET_WILDCARD_CERT_VERSION=v1
+SECRET_WILDCARD_KEY_VERSION=v1
+COMPOSE_FILE="$COMPOSE_FILE:compose.wildcard.yml"
+```
+2. Generate a self-signed certificate using the [command listed here](https://letsencrypt.org/docs/certificates-for-localhost/#making-and-trusting-your-own-certificates). Unless using `localhost` you may want to edit that where it appears in the command, and/or add multiple (sub)domains to the certificate e.g: `subjectAltName=DNS:localhost,DNS:myapp.localhost`
+3. Run these commands:
+```
+abra app secret insert localhost ssl_cert v1 "$(cat localhost.crt)"
+abra app secret insert localhost ssl_key v1 "$(cat localhost.key)"
+```
+4. Re-deploy `traefik` with `--force` and voila!