Our RACHEL Pi custom designed servers described by my friend above are used in remote village schools in Uganda which are mostly powered by 12 volt solar panels; power shutdowns and voltage brownouts can occur randomly. The inexpensive supercaps we use in our design are able to hold power for up to 30 seconds until the Pi completes its shutdown sequence.
The 90 second power shutdown delay that has shown up in the latest images of RACHEL with Kolibri now creates a real problem for future deployments. Our Python script uses a “os.system(sudo shutdown -h now)” command line to shut down the Pi after detecting the push button off signal on a GPIO pin. Before installing Kolibri shutdown always occurred immediately. Shutdown also occurs immediately now when we add the “sudo systemctl stop kolibri” and “sudo systemctl disable kolibri” terminal commands you suggested trying.
After we installed Kolibri we set up the facility first and then imported several Gbs of Khan Academy lessons. Everything runs fine and we are assuming that we set up the facility correctly. However, one or both of the following two messages always comes up and persists for 1 min. 30 secs before shutdown: “A stop job is running for session C1 of LSB Kolibri daemon” or a “A stop job is running for session C1 of user pi”. This continues to show up even after many successive boots and shutdowns. Unfortunately this does not seem to match what you are seeing on your end!
The “systemctl stop kolibri” command line that we have added to our Python script before the “sudo shutdown -h now” line adds about 20 seconds to the power down process. It’s a hack, but we don’t seem to have a better alternative yet. Any suggestions will be appreciated!