synapse/debian/matrix-synapse.service

[Unit]
Description=Synapse Matrix homeserver

[Service]
Type=simple
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/
Restart=always
RestartSec=3

[Install]
WantedBy=multi-user.target