Reboot Strategies¶

rebootmgr supports different strategies, when a reboot should be done:

instantly

maint-window

etcd-lock

best-effort

off

The reboot strategy can be configured via rebootmgr.conf(5) and adjusted at runtime via rebootmgrctl(1). This changes will be written to the configuration file and survive the next reboot.

Locking via etcd¶

To make sure that not all machines reboot at the same time, the machines can be sorted into groups and the number of machines of a group which are allowed to reboot at the same time can be configured and controlled via etcd. So you can create a group etcd_server, which contains all machines running etcd, and specify that only one etcd server is allowed to reboot at one time. And a second group worker, in which a higher number of machines are allowed to reboot at the same time.

The etcd path to the directory containing data for a group is: /opensuse.org/rebootmgr/locks/<group>/. This directory contains two variables: mutex, which is by default 0 and can be set via atomic_compare_and_swap to 1 to make sure that only one machine has write access, and a variable data containing the following json structure:

	{
	  "max":1,
	  "holders":[]
	}


      

holders will contain a unique ID of the machines holding a lock. As unique ID the machine ID from /etc/machine-id is used.

So a record containing two locks out of 10 possible would look like:

	{
	  "max":10,
	  "holders":[
	    "3cb8c701b4d3474d99a7e88b31dd3439",
	    "71c8efe539b280af2fe09b3b5771345e"
	  ]
	}


      

A typical work-flow of a client which tries to reboot would look like: