Make systemd-with-workers doc official (#7234)

Simplify and update this documentation, and make it part of the core dist.

6 files changed, 160 insertions, 15 deletions

diff --git a/docs/systemd-with-workers/README.md b/docs/systemd-with-workers/README.md
new file mode 100644
index 0000000000..257c09446f
--- /dev/null
+++ b/docs/systemd-with-workers/README.md
@@ -0,0 +1,67 @@
+# Setting up Synapse with Workers and Systemd
+
+This is a setup for managing synapse with systemd, including support for
+managing workers. It provides a `matrix-synapse` service for the master, as
+well as a `matrix-synapse-worker@` service template for any workers you
+require. Additionally, to group the required services, it sets up a
+`matrix-synapse.target`.
+
+See the folder [system](system) for the systemd unit files.
+
+The folder [workers](workers) contains an example configuration for the
+`federation_reader` worker.
+
+## Synapse configuration files
+
+See [workers.md](../workers.md) for information on how to set up the
+configuration files and reverse-proxy correctly. You can find an example worker
+config in the [workers](workers) folder.
+
+Systemd manages daemonization itself, so ensure that none of the configuration
+files set either `daemonize` or `worker_daemonize`.
+
+The config files of all workers are expected to be located in
+`/etc/matrix-synapse/workers`. If you want to use a different location, edit
+the provided `*.service` files accordingly.
+
+There is no need for a separate configuration file for the master process.
+
+## Set up
+
+1. Adjust synapse configuration files as above.
+1. Copy the `*.service` and `*.target` files in [system](system) to
+`/etc/systemd/system`.
+1. Run `systemctl deamon-reload` to tell systemd to load the new unit files.
+1. Run `systemctl enable matrix-synapse.service`. This will configure the
+synapse master process to be started as part of the `matrix-synapse.target`
+target.
+1. For each worker process to be enabled, run `systemctl enable
+matrix-synapse-worker@<worker_name>.service`. For each `<worker_name>`, there
+should be a corresponding configuration file
+`/etc/matrix-synapse/workers/<worker_name>.yaml`.
+1. Start all the synapse processes with `systemctl start matrix-synapse.target`.
+1. Tell systemd to start synapse on boot with `systemctl enable matrix-synapse.target`/
+
+## Usage
+
+Once the services are correctly set up, you can use the following commands
+to manage your synapse installation:
+
+```sh
+# Restart Synapse master and all workers
+systemctl restart matrix-synapse.target
+
+# Stop Synapse and all workers
+systemctl stop matrix-synapse.target
+
+# Restart the master alone
+systemctl start matrix-synapse.service
+
+# Restart a specific worker (eg. federation_reader); the master is
+# unaffected by this.
+systemctl restart matrix-synapse-worker@federation_reader.service
+
+# Add a new worker (assuming all configs are set up already)
+systemctl enable matrix-synapse-worker@federation_writer.service
+systemctl restart matrix-synapse.target
+```
diff --git a/docs/systemd-with-workers/system/matrix-synapse-worker@.service b/docs/systemd-with-workers/system/matrix-synapse-worker@.service
new file mode 100644
index 0000000000..70589a7a51
--- /dev/null
+++ b/docs/systemd-with-workers/system/matrix-synapse-worker@.service
@@ -0,0 +1,20 @@
+[Unit]
+Description=Synapse %i
+
+# This service should be restarted when the synapse target is restarted.
+PartOf=matrix-synapse.target
+
+[Service]
+Type=notify
+NotifyAccess=main
+User=matrix-synapse
+WorkingDirectory=/var/lib/matrix-synapse
+EnvironmentFile=/etc/default/matrix-synapse
+ExecStart=/opt/venvs/matrix-synapse/bin/python -m synapse.app.generic_worker --config-path=/etc/matrix-synapse/homeserver.yaml --config-path=/etc/matrix-synapse/conf.d/ --config-path=/etc/matrix-synapse/workers/%i.yaml
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=always
+RestartSec=3
+SyslogIdentifier=matrix-synapse-%i
+
+[Install]
+WantedBy=matrix-synapse.target
diff --git a/docs/systemd-with-workers/system/matrix-synapse.service b/docs/systemd-with-workers/system/matrix-synapse.service
new file mode 100644
index 0000000000..c7b5ddfa49
--- /dev/null
+++ b/docs/systemd-with-workers/system/matrix-synapse.service
@@ -0,0 +1,21 @@
+[Unit]
+Description=Synapse master
+
+# This service should be restarted when the synapse target is restarted.
+PartOf=matrix-synapse.target
+
+[Service]
+Type=notify
+NotifyAccess=main
+User=matrix-synapse
+WorkingDirectory=/var/lib/matrix-synapse
+EnvironmentFile=/etc/default/matrix-synapse
+ExecStartPre=/opt/venvs/matrix-synapse/bin/python -m synapse.app.homeserver --config-path=/etc/matrix-synapse/homeserver.yaml --config-path=/etc/matrix-synapse/conf.d/ --generate-keys
+ExecStart=/opt/venvs/matrix-synapse/bin/python -m synapse.app.homeserver --config-path=/etc/matrix-synapse/homeserver.yaml --config-path=/etc/matrix-synapse/conf.d/
+ExecReload=/bin/kill -HUP $MAINPID
+Restart=always
+RestartSec=3
+SyslogIdentifier=matrix-synapse
+
+[Install]
+WantedBy=matrix-synapse.target
diff --git a/docs/systemd-with-workers/system/matrix-synapse.target b/docs/systemd-with-workers/system/matrix-synapse.target
new file mode 100644
index 0000000000..e0eba1b342
--- /dev/null
+++ b/docs/systemd-with-workers/system/matrix-synapse.target
@@ -0,0 +1,6 @@
+[Unit]
+Description=Synapse parent target
+After=network.target
+
+[Install]
+WantedBy=multi-user.target
diff --git a/docs/systemd-with-workers/workers/federation_reader.yaml b/docs/systemd-with-workers/workers/federation_reader.yaml
new file mode 100644
index 0000000000..5b65c7040d
--- /dev/null
+++ b/docs/systemd-with-workers/workers/federation_reader.yaml
@@ -0,0 +1,13 @@
+worker_app: synapse.app.federation_reader
+
+worker_replication_host: 127.0.0.1
+worker_replication_port: 9092
+worker_replication_http_port: 9093
+
+worker_listeners:
+    - type: http
+      port: 8011
+      resources:
+          - names: [federation]
+
+worker_log_config: /etc/matrix-synapse/federation-reader-log.yaml
diff --git a/docs/workers.md b/docs/workers.md
index cf460283d5..2ce2259b22 100644
--- a/docs/workers.md
+++ b/docs/workers.md
@@ -52,24 +52,20 @@ synapse process.)
 
 You then create a set of configs for the various worker processes.  These
 should be worker configuration files, and should be stored in a dedicated
-subdirectory, to allow synctl to manipulate them. An additional configuration
-for the master synapse process will need to be created because the process will
-not be started automatically. That configuration should look like this:
-
-    worker_app: synapse.app.homeserver
-    daemonize: true
+subdirectory, to allow synctl to manipulate them.
 
 Each worker configuration file inherits the configuration of the main homeserver
 configuration file.  You can then override configuration specific to that worker,
 e.g. the HTTP listener that it provides (if any); logging configuration; etc.
 You should minimise the number of overrides though to maintain a usable config.
 
-You must specify the type of worker application (`worker_app`). The currently
-available worker applications are listed below. You must also specify the
-replication endpoints that it's talking to on the main synapse process.
-`worker_replication_host` should specify the host of the main synapse,
-`worker_replication_port` should point to the TCP replication listener port and
-`worker_replication_http_port` should point to the HTTP replication port.
+In the config file for each worker, you must specify the type of worker
+application (`worker_app`). The currently available worker applications are
+listed below. You must also specify the replication endpoints that it's talking
+to on the main synapse process.  `worker_replication_host` should specify the
+host of the main synapse, `worker_replication_port` should point to the TCP
+replication listener port and `worker_replication_http_port` should point to
+the HTTP replication port.
 
 Currently, the `event_creator` and `federation_reader` workers require specifying
 `worker_replication_http_port`.
@@ -90,8 +86,6 @@ For instance:
          - names:
            - client
 
-    worker_daemonize: True
-    worker_pid_file: /home/matrix/synapse/synchrotron.pid
     worker_log_config: /home/matrix/synapse/config/synchrotron_log_config.yaml
 
 ...is a full configuration for a synchrotron worker instance, which will expose a
@@ -101,7 +95,31 @@ by the main synapse.
 Obviously you should configure your reverse-proxy to route the relevant
 endpoints to the worker (`localhost:8083` in the above example).
 
-Finally, to actually run your worker-based synapse, you must pass synctl the -a
+Finally, you need to start your worker processes. This can be done with either
+`synctl` or your distribution's preferred service manager such as `systemd`. We
+recommend the use of `systemd` where available: for information on setting up
+`systemd` to start synapse workers, see
+[systemd-with-workers](systemd-with-workers). To use `synctl`, see below.
+
+### Using synctl
+
+If you want to use `synctl` to manage your synapse processes, you will need to
+create an an additional configuration file for the master synapse process. That
+configuration should look like this:
+
+```yaml
+worker_app: synapse.app.homeserver
+```
+
+Additionally, each worker app must be configured with the name of a "pid file",
+to which it will write its process ID when it starts. For example, for a
+synchrotron, you might write:
+
+```yaml
+worker_pid_file: /home/matrix/synapse/synchrotron.pid
+```
+
+Finally, to actually run your worker-based synapse, you must pass synctl the `-a`
 commandline option to tell it to operate on all the worker configurations found
 in the given directory, e.g.: