Merge pull request #199 from wabuMike/master

Added a basic guide on migrating to another server

docs/installing.md

@@ -39,3 +39,4 @@ Now that the services are running, you might want to:
 - or [set up the Dimension Integrations Manager](configuring-playbook-dimension.md)
 - or [check if services work](maintenance-checking-services.md)
 - or learn how to [upgrade your services when new versions are released](maintenance-upgrading-services.md)
+- or learn how to [migrate to another server](maintenance-migrating.md)

docs/maintenance-migrating.md

@@ -0,0 +1,8 @@
+# Migrating to new server
+
+1. Prepare by lowering DNS TTL for your domains (`matrix.DOMAIN`, etc.), so that DNS record changes (step 4 below) would happen faster, leading ot less downtime
+2. Stop all services on the old server and make sure they won't be starting again. Execute this on the old server: `systemctl disable --now matrix*` 
+3. Copy directory `/matrix` from the old server to the new server. Make sure to preserve ownership and permissions (use `cp -p` or `rsync -ar`)!
+4. Make sure your DNS records are adjusted to point to the new server's IP address
+5. Remove old server from the `inventory/hosts` file and add new server.
+6. Run `ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start`. This will create the matrix user and group and start all services on the new server