After a deeper look, it seems related to the condor.service on ubuntu:
######################################################################
[Unit]
Description=Condor Distributed High-Throughput-Computing
After=syslog.target network-online.target nslcd.service ypbind.service autofs.service
Wants=network-online.target
# Disabled until HTCondor security fixed.
# Requires=condor.socket
[Service]
Environment=CONDOR_CONFIG=/condor/install_centos/etc/condor_config
ExecStart=/condor/install_ubuntu/sbin/condor_master -f
ExecStop=/condor/install_ubuntu/sbin/condor_off -master
ExecReload=/bin/kill -HUP $MAINPID
Restart=always
RestartSec=1minute
WatchdogSec=20minutes
TimeoutStopSec=90seconds
StandardOutput=syslog
NotifyAccess=main
KillSignal=SIGKILL
LimitNOFILE=16384
[Install]
WantedBy=multi-user.target
######################################################################
The WatchdogSec is set to 20 minutes and it seems there is no keep-alive ping during this interval forcing the service to restart. I'm not familiar with systemd but my first idea is to remove the WatchdogSec. I took the condor.service file in
the example directory of the depot but maybe is not the right one.
My manager central manager is on Centos with the same condor.service and do not have this problem of restarting every 20 mins.