- cherry-pick "Ensure worker config exists in systemd service (#7528)" from synapse d74cdc1a42e8b487d74c214b1d0ca575429d546a: "check that the worker config file exists instead of silently failing."
· needs documentation; no checks yet for port clashes or typos in worker name · according to https://github.com/matrix-org/synapse/wiki/Workers-setup-with-nginx#results about 90% of requests go to the synchrotron endpoint · thus, the synchrotron worker is especially suited to be load-balanced · most of the other workers are documented to support only a single instance · https://github.com/matrix-org/synapse/blob/master/docs/workers.md