diff --git a/ha-manager.adoc b/ha-manager.adoc index 54db2a5..038193f 100644 --- a/ha-manager.adoc +++ b/ha-manager.adoc @@ -933,6 +933,51 @@ NOTE: Please do not 'kill' services like `pve-ha-crm`, `pve-ha-lrm` or immediate node reboot or even reset. +Scheduler Mode +-------------- + +The scheduler mode controls how HA selects nodes for the recovery of a service +as well as for migrations that are triggered by a shutdown policy. The default +mode is `basic`, you can change it in `datacenter.cfg`: + +---- +crs: ha=static +---- + +The change will be in effect when a new master takes over. This can be triggered +by executing the following on the current master's node: + +---- +systemctl reload-or-restart pve-ha-crm.service +---- + +For each service that needs to be recovered or migrated, the scheduler +iteratively chooses the best node among the nodes with the highest priority in +the service's group. + +NOTE: There are plans to add modes for (static and dynamic) load-balancing in +the future. + +Basic +^^^^^ + +The number of active HA serivces on each node is used to choose a recovery node. + +Static +^^^^^^ + +Static usage information from HA serivces on each node is used to choose a +recovery node. + +For this selection, each node in turn is considered as if the service was +already running on it, using CPU and memory usage from the associated guest +configuration. Then for each such alternative, CPU and memory usage of all nodes +are considered, with memory being weighted much more, because it's a truly +limited resource. For both, CPU and memory, highest usage among nodes (weighted +more, as ideally no node should be overcommitted) and average usage of all nodes +(to still be able to distinguish in case there already is a more highly +committed node) are considered. + ifdef::manvolnum[] include::pve-copyright.adoc[] endif::manvolnum[]