mirror of
https://github.com/openshift/openshift-docs.git
synced 2026-02-05 12:46:18 +01:00
31 lines
1.4 KiB
Plaintext
31 lines
1.4 KiB
Plaintext
// Module included in the following assemblies:
|
|
//
|
|
// * nodes/nodes-scheduler-default.adoc
|
|
|
|
:_mod-docs-content-type: CONCEPT
|
|
[id="nodes-scheduler-default-about_{context}"]
|
|
= Understanding default scheduling
|
|
|
|
The existing generic scheduler is the default platform-provided scheduler
|
|
_engine_ that selects a node to host the pod in a three-step operation:
|
|
|
|
Filters the nodes::
|
|
The available nodes are filtered based on the constraints or requirements
|
|
specified. This is done by running each node through the list of filter
|
|
functions called _predicates_, or _filters_.
|
|
|
|
Prioritizes the filtered list of nodes::
|
|
This is achieved by passing each node through a series of _priority_, or _scoring_, functions
|
|
that assign it a score between 0 - 10, with 0 indicating a bad fit and 10
|
|
indicating a good fit to host the pod. The scheduler configuration can also take
|
|
in a simple _weight_ (positive numeric value) for each scoring function. The
|
|
node score provided by each scoring function is multiplied by the weight
|
|
(default weight for most scores is 1) and then combined by adding the scores for each node
|
|
provided by all the scores. This weight attribute can be used by
|
|
administrators to give higher importance to some scores.
|
|
|
|
Selects the best fit node::
|
|
The nodes are sorted based on their scores and the node with the highest score
|
|
is selected to host the pod. If multiple nodes have the same high score, then
|
|
one of them is selected at random.
|