Service is unable to (re)start: failed to setup mmm: database at ./data is already in use by another instance

[Sebastix]

This issue has been addressed already in several chats and it's getting back at us, so let's summarize it in a issue here.

My pyramid instance has been unable to restart for multiple times for the same reason:

FTL couldn't initialize error="failed to setup mmm: database at ./data is already in use by another instance"

and it seems to happen when my machine has booted (due some power outages, it's turned off suddenly multiple times but it's always booting when the power is back on). It might have something to do when the service is unexpectely stopped.

For now I have always deleted the ./data/mmmm.lock file to get my pyramid instance running again.

[xdamman]

Same issue here.

[fiatjaf]

That file is there only to ensure that multiple instances don't try to access the same database at the same time, which would cause problems. The server deletes that file when it's shut down. But when the server crashes it doesn't delete, so you have to delete it manually.

It's ok to just delete it if you know no pyramid instance is running.

If someone knows a better way to prevent the database from being accessed by two instances simultaneously that doesn't suffer from such problems please let me know.

[pcwd]

You could add:

ExecStartPre=/usr/bin/rm -f /home/user/pyramid/data/mmmm.lock

to the pyramid.service file.

If the program crashes, systemd will automatically delete the lock file before restarting it.

Replace 'user' with the directory name you've installed pyramid into.

[Sebastix]

@pcwd 👍

This is my current systemd file for the pyramid relay service

[Unit]
Description=inner-relay
After=network-online.target

[Service]
Type=simple
WorkingDirectory=/var/www/<pyramid_dir>
User=<your_username>
ExecStartPre=/usr/bin/rm -f /var/www/<pyramid_dir>/data/mmmm.lock
ExecStart=/var/www/<pyramid_dir>/pyramid
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target

And I haven't had the issue since this change.