This playbook can install and configure [Matrix Authentication Service](https://github.com/element-hq/matrix-authentication-service/) (MAS) - a service operating alongside your existing [Synapse](./configuring-playbook-synapse.md) homeserver and providing [better authentication, session management and permissions in Matrix](https://matrix.org/blog/2023/09/better-auth/).
Matrix Authentication Service is an implementation of [MSC3861: Next-generation auth for Matrix, based on OAuth 2.0/OIDC](https://github.com/matrix-org/matrix-spec-proposals/pull/3861) and still work in progress, tracked at the [areweoidcyet.com](https://areweoidcyet.com/) website.
**Before going through with starting to use Matrix Authentication Service**, make sure to read:
- the [Reasons to use Matrix Authentication Service](#reasons-to-use-matrix-authentication-service) section below
- the [Expectations](#expectations) section below
- the [FAQ section on areweoidcyet.com](https://areweoidcyet.com/#faqs)
**If you've already been using Synapse** and have user accounts in its database, you can [migrate to Matrix Authentication Service](#migrating-an-existing-homeserver-to-matrix-authentication-service).
## Reasons to use Matrix Authentication Service
You may be wondering whether you should make the switch to Matrix Authentication Service (MAS) or keep using your existing authentication flow via Synapse (password-based or [OIDC](./configuring-playbook-synapse.md#synapse--openid-connect-for-single-sign-on)-enabled).
Matrix Authentication Service is **still an experimental service** and **not a default** for this Ansible playbook.
The [Expectations](#expectations) section contains a list of what works and what doesn't (**some services don't work with MAS yet**), as well as the **relative irreversability** of the migration process.
Below, we'll try to **highlight some potential reasons for switching** to Matrix Authentication Service:
- To use SSO in [Element X](https://element.io/blog/element-x-ignition/). The old [Synapse OIDC](./configuring-playbook-synapse.md#synapse--openid-connect-for-single-sign-on) login flow is only supported in old Element clients and will not be supported in Element X. Element X will only support the new SSO-based login flow provided by MAS, so if you want to use SSO with Element X, you will need to switch to MAS.
- To help drive adoption of the "Next-generation auth for Matrix" by switching to what's ultimately coming anyway
- To help discover (and potentially fix) MAS integration issues with this Ansible playbook
- To help discover (and potentially fix) MAS integration issues with various other Matrix components (bridges, bots, clients, etc.)
- To reap some of the security benefits that Matrix Authentication Service offers, as outlined in the [Better authentication, session management and permissions in Matrix](https://matrix.org/blog/2023/09/better-auth/) article.
## Prerequisites
- ⚠ the [Synapse](configuring-playbook-synapse.md) homeserver implementation (which is the default for this playbook). Other homeserver implementations ([Dendrite](./configuring-playbook-dendrite.md), [Conduit](./configuring-playbook-conduit.md), etc.) do not support integrating wtih Matrix Authentication Service yet.
- ⚠ **email sending** configured (see [Adjusting email-sending settings](./configuring-playbook-email.md)), because **Matrix Authentication Service [still insists](https://github.com/element-hq/matrix-authentication-service/issues/1505) on having a verified email address for each user** going through the new SSO-based login flow. It's also possible to [work around email deliverability issues](#working-around-email-deliverability-issues) if your email configuration is not working.
- ❌ **disabling all password providers** for Synapse (things like [shared-secret-auth](./configuring-playbook-shared-secret-auth.md), [rest-auth](./configuring-playbook-rest-auth.md), [LDAP auth](./configuring-playbook-ldap-auth.md), etc.) More details about this are available in the [Expectations](#expectations) section below.
## Expectations
This section details what you can expect when switching to the Matrix Authentication Service (MAS).
- ❌ **Synapse password providers will need to be disabled**. You can no longer use [shared-secret-auth](./configuring-playbook-shared-secret-auth.md), [rest-auth](./configuring-playbook-rest-auth.md), [LDAP auth](./configuring-playbook-ldap-auth.md), etc. When the authentication flow is handled by MAS (not by Synapse anymore), it doesn't make sense to extend the Synapse authentication flow with additional modules. Many bridges used to rely on shared-secret-auth for doing double-puppeting (impersonating other users), but most (at least the mautrix bridges) nowadays use [Appservice Double Puppet](./configuring-playbook-appservice-double-puppet.md) as a better alternative. Older/maintained bridges may still rely on shared-secret-auth, as do other services like [matrix-corporal](./configuring-playbook-matrix-corporal.md).
- ❌ Certain **tools like [synapse-admin](./configuring-playbook-synapse-admin.md) do not have full compatibility with MAS yet**. synapse-admin already supports [login with access token](https://github.com/etkecc/synapse-admin/pull/58), browsing users (which Synapse will internally fetch from MAS) and updating user avatars. However, editing users (passwords, etc.) now needs to happen directly against MAS using the [MAS Admin API](https://element-hq.github.io/matrix-authentication-service/api/index.html), which synapse-admin cannot interact with yet.
- ❌ **Some services** (e.g. [Postmoogle](./configuring-playbook-bot-postmoogle.md), but possibly others - the list is yet to be determined) appear to **experience issues when authenticating via MAS**. We're still investigating what breaks and why.
- ⚠ **You will need to have email sending configured** (see [Adjusting email-sending settings](./configuring-playbook-email.md)), because **Matrix Authentication Service [still insists](https://github.com/element-hq/matrix-authentication-service/issues/1505) on having a verified email address for each user** going through the new SSO-based login flow. It's also possible to [work around email deliverability issues](#working-around-email-deliverability-issues) if your email configuration is not working.
- ⚠ **Migrating an existing homeserver to MAS is possible**, but requires **some playbook-assisted manual work** as described in the [Migrating an existing homeserver to Matrix Authentication Service](#migrating-an-existing-homeserver-to-matrix-authentication-service) section below. **Migration is reversible with no or minor issues if done quickly enough**, but as users start logging in (creating new login sessions) via the new MAS setup, disabling MAS and reverting back to the Synapse user database will cause these new sessions to break.
- ⚠ Delegating user authentication to MAS causes **your Synapse server to be completely dependant on one more service** for its operations. MAS is quick & lightweight and should be stable enough already, but this is something to keep in mind when making the switch.
- ⚠ If you've got [OIDC configured in Synapse](./configuring-playbook-synapse.md#synapse--openid-connect-for-single-sign-on), you will need to migrate your OIDC configuration to MAS by adding an [Upstream OAuth2 configuration](#upstream-oauth2-configuration).
- ⚠ A [compatibility layer](https://element-hq.github.io/matrix-authentication-service/setup/homeserver.html#set-up-the-compatibility-layer) is installed - all `/_matrix/client/*/login` (etc.) requests will be routed to MAS instead of going to the homeserver. This is done both publicly (e.g. `https://matrix.example.com/_matrix/client/*/login`) and on the internal Traefik entrypoint (e.g. `https://matrix-traefik:8008/_matrix/client/*/login`) which helps addon services reach the homeserver's Client-Server API. You typically don't need to do anything to make this work, but it's good to be aware of it, especially if you have a [custom webserver setup](./configuring-playbook-own-webserver.md).
- ✅ Your **existing login sessions will continue to work** (you won't get logged out). Migration will require a bit of manual work and minutes of downtime, but it's not too bad.
- ✅ Various clients ([Cinny](./configuring-playbook-client-cinny.md), [Element-web](./configuring-playbook-client-element.md), Element X, FluffyChat) will be able to use the **new SSO-based login flow** provided by Matrix Authentication Service
- ✅ The **old login flow** (called `m.login.password`) **will still continue to work**, so clients (old Element, etc.) and bridges/bots that don't support the new OIDC-based login flow will still work. Going through the old login flow does not require users to have a verified email address, as [is the case](https://github.com/element-hq/matrix-authentication-service/issues/1505) for the new SSO-based login flow.
- ✅ [Registering users](./registering-users.md) via **the playbook's `register-user` tag remains unchanged**. The playbook automatically does the right thing regardless of homeserver implementation (Synapse, Dendrite, etc.) and whether MAS is enabled or not. When MAS is enabled, the playbook will forward user-registration requests to MAS. Registering users via the command-line is no longer done via the `/matrix/synapse/bin/register` script, but via `/matrix/matrix-authentication-service/bin/register-user`.
- ✅ Users that are prepared by the playbook (for bots, bridges, etc.) will continue to be registered automatically as expected. The playbook automatically does the right thing regardless of homeserver implementation (Synapse, Dendrite, etc.) and whether MAS is enabled or not. When MAS is enabled, the playbook will forward user-registration requests to MAS.
## Installation flows
### New homeserver
For new homeservers (which don't have any users in their Synapse database yet), follow the [Adjusting the playbook configuration](#adjusting-the-playbook-configuration) instructions and then proceed with [Installing](#installing).
### Existing homeserver
Other homeserver implementations ([Dendrite](./configuring-playbook-dendrite.md), [Conduit](./configuring-playbook-conduit.md), etc.) do not support integrating wtih Matrix Authentication Service yet.
For existing Synapse homeservers:
- when following the [Adjusting the playbook configuration](#adjusting-the-playbook-configuration) instructions, make sure to **disable the integration between Synapse and MAS** by **uncommenting** the `matrix_authentication_service_migration_in_progress: true` line as described in the [Marking an existing homeserver for migration](#marking-an-existing-homeserver-for-migration) section below.
- then follow the [Migrating an existing homeserver to Matrix Authentication Service](#migrating-an-existing-homeserver-to-matrix-authentication-service) instructions to perform the installation and migration
In the sub-sections that follow, we'll cover some additional configuration options that you may wish to adjust.
There are many other configuration options available. Consult the [`defaults/main.yml` file](../roles/custom/matrix-authentication-service/defaults/main.yml) in the [matrix-authentication-service role](../roles/custom/matrix-authentication-service/) to discover them.
### Adjusting the Matrix Authentication Service URL
By default, this playbook installs the Matrix Authentication Service on the `matrix.` subdomain, at the `/auth` path (https://matrix.example.com/auth). This makes it easy to install it, because it **doesn't require additional DNS records to be set up**. If that's okay, you can skip this section.
By tweaking the `matrix_authentication_service_hostname` and `matrix_authentication_service_path_prefix` variables, you can easily make the service available at a **different hostname and/or path** than the default one.
Example additional configuration for your `inventory/host_vars/matrix.example.com/vars.yml` file:
The [configuration above](#adjusting-the-playbook-configuration) instructs existing users wishing to migrate to add `matrix_authentication_service_migration_in_progress: true` to their configuration.
This is done temporarily. The migration steps are described in more detail in the [Migrating an existing homeserver to Matrix Authentication Service](#migrating-an-existing-homeserver-to-matrix-authentication-service) section below.
### Upstream OAuth2 configuration
To make Matrix Authentication Service delegate to an existing upstream OAuth 2.0/OIDC provider, you can use its [`upstream_oauth2.providers` setting](https://element-hq.github.io/matrix-authentication-service/reference/configuration.html#upstream_oauth2providers).
The playbook exposes a `matrix_authentication_service_config_upstream_oauth2_providers` variable for controlling this setting.
<details>
<summary>Click to expand the example configuration:</summary>
Example additional configuration for your `inventory/host_vars/matrix.example.com/vars.yml` file:
# Whether the email address must be marked as verified.
# Possible values are:
# - `import`: mark the email address as verified if the upstream provider
# has marked it as verified, using the `email_verified` claim.
# This is the default.
# - `always`: mark the email address as verified
# - `never`: mark the email address as not verified
#set_email_verification: import
```
</details>
💡 Refer to the [`upstream_oauth2.providers` setting](https://element-hq.github.io/matrix-authentication-service/reference/configuration.html#upstream_oauth2providers) for the most up-to-date schema and example for providers. The value shown above here may be out of date.
⚠ The syntax for existing [OIDC providers configured in Synapse](./configuring-playbook-synapse.md#synapse--openid-connect-for-single-sign-on) is slightly different, so you will need to adjust your configuration when switching from Synapse OIDC to MAS upstream OAuth2.
If you've changed the default hostname, **you may need to adjust your DNS** records to point the Matrix Authentication Service domain to the Matrix server.
See [Configuring DNS](configuring-dns.md) for details about DNS changes.
If you've decided to use the default hostname, you won't need to do any extra DNS configuration.
Now that you've [adjusted the playbook configuration](#adjusting-the-playbook-configuration) and [your DNS records](#adjusting-dns-records), you can run the [installation](installing.md) command: `just install-all`
If you're in the process of migrating an existing Synapse homeserver to MAS, you should now follow the rest of the steps in the [Migrating an existing homeserver to Matrix Authentication Service](#migrating-an-existing-homeserver-to-matrix-authentication-service) guide.
💡 After installation, you should [verify that Matrix Authentication Service is installed correctly](#verify-that-matrix-authentication-service-is-installed-correctly).
## Migrating an existing Synapse homeserver to Matrix Authentication Service
Our migration guide is loosely based on the upstream [Migrating an existing homeserver](https://element-hq.github.io/matrix-authentication-service/setup/migration.html) guide.
Migration is done via a tool called `syn2mas`, which the playbook could run for you (in a container).
The installation + migration steps are like this:
1. [Adjust your configuration](#adjusting-the-playbook-configuration) to **disable the integration between the homeserver and MAS**. This is done by **uncommenting** the `matrix_authentication_service_migration_in_progress: true` line.
2. Perform the initial [installation](#installing). At this point:
- Matrix Authentication Service will be installed. Its database will be empty, so it cannot validate existing access tokens or authentication users yet.
- The homeserver will still continue to use its local database for validating existing access tokens.
- Various [compatibility layer URLs](https://element-hq.github.io/matrix-authentication-service/setup/homeserver.html#set-up-the-compatibility-layer) are not yet installed. New login sessions will still be forwarded to the homeserver, which is capable of completing them.
- The `matrix-user-creator` role would be suppressed, so that it doesn't automatically attempt to create users (for bots, etc.) in the MAS database. These user accounts likely already exist in Synapse's user database and could be migrated over (via syn2mas, as per the steps below), so creating them in the MAS database would have been unnecessary and potentially problematic (conflicts during the syn2mas migration).
3. Consider taking a full [backup of your Postgres database](./maintenance-postgres.md#backing-up-postgresql). This is done just in case. The **syn2mas migration tool does not delete any data**, so it should be possible to revert to your previous setup by merely disabling MAS and re-running the playbook (no need to restore a Postgres backup). However, do note that as users start logging in (creating new login sessions) via the new MAS setup, disabling MAS and reverting back to the Synapse user database will cause these new sessions to break.
4. [Migrate your data from Synapse to Matrix Authentication Service using syn2mas](#migrate-your-data-from-synapse-to-matrix-authentication-service-using-syn2mas)
5. [Adjust your configuration](#adjusting-the-playbook-configuration) again, removing the `matrix_authentication_service_migration_in_progress: false` line
5. Perform the [installation](#installing) again. At this point:
- The homeserver will start delegating authentication to MAS.
- The compatibility layer URLs will be installed. New login sessions will be completed by MAS.
6. [Verify that Matrix Authentication Service is installed correctly](#verify-that-matrix-authentication-service-is-installed-correctly)
### Migrate your data from Synapse to Matrix Authentication Service using syn2mas
We **don't** ask you to [run the `syn2mas` migration advisor command](https://element-hq.github.io/matrix-authentication-service/setup/migration.html#run-the-migration-advisor), because it only gives you the green light if your Synapse configuration (`homeserver.yaml`) is configured in a way that's compatible with MAS (delegating authentication to MAS; disabling Synapse's password config; etc.). Until we migrate your data with the `syn2mas` tool, we intentionally avoid doing these changes to allow existing user sessions to work.
You can invoke the `syn2mas` tool via the playbook by running the playbook's `matrix-authentication-service-syn2mas` tag. We recommend first doing a [dry-run](#performing-a-syn2mas-dry-run) and then a [real migration](#performing-a-real-syn2mas-migration).
#### Performing a syn2mas dry-run
We recommend doing a [dry-run](https://en.wikipedia.org/wiki/Dry_run_(testing)) first to verify that everything will work out as expected.
A dry-run would not cause downtime, because it avoids stopping Synapse.
To perform a dry-run, run:
```sh
just run-tags matrix-authentication-service-syn2mas -e matrix_authentication_service_syn2mas_dry_run=true
```
Observe the command output (especially the last line of the the syn2mas output). If you are confident that the migration will work out as expected, you can proceed with a [real migration](#performing-a-real-syn2mas-migration).
#### Performing a real syn2mas migration
Before performing a real migration:
- make sure you've familiarized yourself with the [expectations](#expectations)
- make sure you've performed a Postgres backup, just in case
- make sure you're aware of the irreversibility of the migration process without disruption after users have created new login sessions via the new MAS setup
To perform a real migration, run the `matrix-authentication-service-syn2mas` tag **without** the `matrix_authentication_service_syn2mas_dry_run` variable:
```sh
just run-tags matrix-authentication-service-syn2mas
```
Having performed a `syn2mas` migration once, trying to do it again will report errors for users that were already migrated (e.g. "Error: Unknown upstream provider oauth-delegated").
## Verify that Matrix Authentication Service is installed correctly
After [installation](#installing), run the `doctor` subcommand of the [`mas-cli` command-line tool](https://element-hq.github.io/matrix-authentication-service/reference/cli/index.html) to verify that MAS is installed correctly.
You can do it:
- either via the Ansible playbook's `matrix-authentication-service-mas-cli-doctor` tag: `just run-tags matrix-authentication-service-mas-cli-doctor`
- or by running the `mas-cli` script on the server (which invokes the `mas-cli` tool inside a container): `/matrix/matrix-authentication-service/bin/mas-cli doctor`
If successful, you should see some output that looks like this:
```
💡 Running diagnostics, make sure that both MAS and Synapse are running, and that MAS is using the same configuration files as this tool.
✅ Matrix client well-known at "https://example.com/.well-known/matrix/client" is valid
✅ Homeserver is reachable at "http://matrix-synapse:8008/_matrix/client/versions"
✅ Homeserver at "http://matrix-synapse:8008/_matrix/client/v3/account/whoami" is reachable, and it correctly rejected an invalid token.
✅ The Synapse admin API is reachable at "http://matrix-synapse:8008/_synapse/admin/v1/server_version".
✅ The Synapse admin API is reachable with authentication at "http://matrix-synapse:8008/_synapse/admin/v1/background_updates/status".
✅ The legacy login API at "https://matrix.example.com/_matrix/client/v3/login" is reachable and is handled by MAS.
```
## Management
You can use the [`mas-cli` command-line tool](https://element-hq.github.io/matrix-authentication-service/reference/cli/index.html) (exposed via the `/matrix/matrix-authentication-service/bin/mas-cli` script) to perform administrative tasks against MAS.
This documentation page already mentions:
- the `mas-cli doctor` sub-command in the [Verify that Matrix Authentication Service is installed correctly](#verify-that-matrix-authentication-service-is-installed-correctly) section, which you can run via the CLI and via the Ansible playbook's `matrix-authentication-service-mas-cli-doctor` tag
- the `mas-cli manage register-user` sub-command in the [Registering users](./registering-users.md) documentation
There are other sub-commands available. Run `/matrix/matrix-authentication-service/bin/mas-cli` to get an overview.
## User registration
After Matrix Authentication Service is [installed](#installing), users need to be managed there (unless you're managing them in an [upstream OAuth2 provider](#upstream-oauth2-configuration)).
You can register users new users as described in the [Registering users](./registering-users.md) documentation (via `mas-cli manage register-user` or the Ansible playbook's `register-user` tag).
## Working around email deliverability issues
Because Matrix Authentication Service [still insists](https://github.com/element-hq/matrix-authentication-service/issues/1505) on having a verified email address for each user, you may need to work around email deliverability issues if [your email-sending configuration](./configuring-playbook-email.md) is not working.
Matrix Authentication Service attempts to verify email addresses by sending a verification email to the address specified by the user whenever they log in to an account without a verified email address.
If email delivery is not working, **you can retrieve the email configuration code from the Matrix Authentication Service's logs** (`journalctl -fu matrix-authentication-service`).
Alternatively, you can use the [`mas-cli` management tool](#management) to manually verify email addresses for users. Example: `/matrix/matrix-authentication-service/bin/mas-cli manage verify-email some.username email@example.com`
