Initial work on using externally defined roles

docs/installing.md

@@ -2,6 +2,9 @@
 
 If you've [configured your DNS](configuring-dns.md) and have [configured the playbook](configuring-playbook.md), you can start the installation procedure.
 
+**Before installing** and each time you update the playbook in the future, you will need to update the Ansible roles in this playbook by running `make roles`.
+
+
 ## Playbook tags introduction
 
 The Ansible playbook's tasks are tagged, so that certain parts of the Ansible playbook can be run without running all other tasks.

docs/maintenance-upgrading-services.md

@@ -10,8 +10,8 @@ To upgrade services:
 
 - take a look at [the changelog](../CHANGELOG.md) to see if there have been any backward-incompatible changes that you need to take care of
 
-- re-run the [playbook setup](installing.md): `ansible-playbook -i inventory/hosts setup.yml --tags=setup-all`
+- download the upstream Ansible roles used by the playbook by running `make roles`
 
-- restart the services: `ansible-playbook -i inventory/hosts setup.yml --tags=start`
+- re-run the [playbook setup](installing.md) and restart all serivces: `ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,ensure-matrix-users-created,start`
 
 **Note**: major version upgrades to the internal PostgreSQL database are not done automatically. To upgrade it, refer to the [upgrading PostgreSQL guide](maintenance-postgres.md#upgrading-postgresql).