From 079bc3c8e35599722630e616115fedd3c29af808 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Thu, 6 Aug 2020 10:35:59 +0100 Subject: [PATCH] Fixup worker doc (again) (#8000) --- changelog.d/8000.doc | 1 + .../workers/federation_reader.yaml | 2 +- docs/workers.md | 54 ++++++++++++++----- 3 files changed, 43 insertions(+), 14 deletions(-) create mode 100644 changelog.d/8000.doc diff --git a/changelog.d/8000.doc b/changelog.d/8000.doc new file mode 100644 index 0000000000..8d8fd926e9 --- /dev/null +++ b/changelog.d/8000.doc @@ -0,0 +1 @@ +Improve workers docs. diff --git a/docs/systemd-with-workers/workers/federation_reader.yaml b/docs/systemd-with-workers/workers/federation_reader.yaml index 5b65c7040d..13e69e62c9 100644 --- a/docs/systemd-with-workers/workers/federation_reader.yaml +++ b/docs/systemd-with-workers/workers/federation_reader.yaml @@ -1,7 +1,7 @@ worker_app: synapse.app.federation_reader +worker_name: federation_reader1 worker_replication_host: 127.0.0.1 -worker_replication_port: 9092 worker_replication_http_port: 9093 worker_listeners: diff --git a/docs/workers.md b/docs/workers.md index 80b65a0cec..bfec745897 100644 --- a/docs/workers.md +++ b/docs/workers.md @@ -23,7 +23,7 @@ The processes communicate with each other via a Synapse-specific protocol called feeds streams of newly written data between processes so they can be kept in sync with the database state. -When configured to do so, Synapse uses a +When configured to do so, Synapse uses a [Redis pub/sub channel](https://redis.io/topics/pubsub) to send the replication stream between all configured Synapse processes. Additionally, processes may make HTTP requests to each other, primarily for operations which need to wait @@ -66,23 +66,31 @@ https://hub.docker.com/r/matrixdotorg/synapse/. To make effective use of the workers, you will need to configure an HTTP reverse-proxy such as nginx or haproxy, which will direct incoming requests to -the correct worker, or to the main synapse instance. See +the correct worker, or to the main synapse instance. See [reverse_proxy.md](reverse_proxy.md) for information on setting up a reverse proxy. -To enable workers you should create a configuration file for each worker -process. Each worker configuration file inherits the configuration of the shared -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. +When using workers, each worker process has its own configuration file which +contains settings specific to that worker, such as the HTTP listener that it +provides (if any), logging configuration, etc. + +Normally, the worker processes are configured to read from a shared +configuration file as well as the worker-specific configuration files. This +makes it easier to keep common configuration settings synchronised across all +the processes. + +The main process is somewhat special in this respect: it does not normally +need its own configuration file and can take all of its configuration from the +shared configuration file. -### Shared Configuration +### Shared configuration + +Normally, only a couple of changes are needed to make an existing configuration +file suitable for use with workers. First, you need to enable an "HTTP replication +listener" for the main process; and secondly, you need to enable redis-based +replication. For example: -Next you need to add both a HTTP replication listener, used for HTTP requests -between processes, and redis config to the shared Synapse configuration file -(`homeserver.yaml`). For example: ```yaml # extend the existing `listeners` section. This defines the ports that the @@ -105,7 +113,7 @@ Under **no circumstances** should the replication listener be exposed to the public internet; it has no authentication and is unencrypted. -### Worker Configuration +### Worker configuration In the config file for each worker, you must specify the type of worker application (`worker_app`), and you should specify a unqiue name for the worker @@ -145,6 +153,9 @@ plain HTTP endpoint on port 8083 separately serving various endpoints, e.g. Obviously you should configure your reverse-proxy to route the relevant endpoints to the worker (`localhost:8083` in the above example). + +### Running Synapse with workers + 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 @@ -407,6 +418,23 @@ all these to be folded into the `generic_worker` app and to use config to define which processes handle the various proccessing such as push notifications. +## Migration from old config + +There are two main independent changes that have been made: introducing Redis +support and merging apps into `synapse.app.generic_worker`. Both these changes +are backwards compatible and so no changes to the config are required, however +server admins are encouraged to plan to migrate to Redis as the old style direct +TCP replication config is deprecated. + +To migrate to Redis add the `redis` config as above, and optionally remove the +TCP `replication` listener from master and `worker_replication_port` from worker +config. + +To migrate apps to use `synapse.app.generic_worker` simply update the +`worker_app` option in the worker configs, and where worker are started (e.g. +in systemd service files, but not required for synctl). + + ## Architectural diagram The following shows an example setup using Redis and a reverse proxy: