Description

Update-engine sends empty requests to an empty URL when the update-engine service is restarted before a pending reboot. This can only be resolved by rebooting or by resetting the update-engine state.

Impact

The instance does not communicate with the update server anymore.

Environment and steps to reproduce

1. Set-up: Run an old Flatcar version with standard settings, but mask locksmith
2. Task: Trigger an update (update_engine_client -update), then restart update-engine.service
3. Action(s): Restart update-engine after the update is written to the partition and update-engine waits for the reboot
4. Error: in the journal one can see that all ping's are now done with empty values

journalctl --no-pager -u update-engine | grep -i "Posting an Omaha request to"
May 25 08:05:54 localhost update_engine[859]: I0525 08:05:54.272867   859 omaha_request_action.cc:268] Posting an Omaha request to https://public.update.flatcar-linux.net/v1/update/
May 25 08:06:01 localhost update_engine[859]: I0525 08:06:01.907414   859 omaha_request_action.cc:268] Posting an Omaha request to https://public.update.flatcar-linux.net/v1/update/
May 25 08:10:33 localhost update_engine[1011]: I0525 08:10:33.162166  1011 omaha_request_action.cc:268] Posting an Omaha request to

Expected behavior
Without restarting the service the pings have the regular values as before the update (except for the update check entry). This is also expected after restarting the service but doesn't work currently.

Additional information
When resetting the update-engine state there may be a crash of the service but it recovers