What does this error means -- holdoff time over, scheduling restart

What does this error means

[root@COMPUTE-NODE1 ~]# systemctl status openstack-nova-compute.service -l
● openstack-nova-compute.service - OpenStack Nova Compute Server
Loaded: loaded (/usr/lib/systemd/system/openstack-nova-compute.service; disabled; vendor preset: disabled)
Active: activating (start) since Fri 2017-02-24 09:45:36 EST; 1s ago
Main PID: 10280 (nova-compute)
CGroup: /system.slice/openstack-nova-compute.service
└─10280 /usr/bin/python2 /usr/bin/nova-compute

Feb 24 09:45:36 COMPUTE-NODE1 systemd[1]: openstack-nova-compute.service holdoff time over, scheduling restart.
Feb 24 09:45:36 COMPUTE-NODE1 systemd[1]: Starting OpenStack Nova Compute Server...