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This commit is contained in:
David Oppenheimer
2015-07-20 00:25:07 -07:00
parent d414e29643
commit 50e95a031b
27 changed files with 86 additions and 86 deletions
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docs/devel/scheduler.md
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@@ -53,30 +53,30 @@ divided by the node's capacity).
Finally, the node with the highest priority is chosen
(or, if there are multiple such nodes, then one of them is chosen at random). The code
for this main scheduling loop is in the function `Schedule()` in
[plugin/pkg/scheduler/generic_scheduler.go](../../plugin/pkg/scheduler/generic_scheduler.go)
[plugin/pkg/scheduler/generic_scheduler.go](http://releases.k8s.io/HEAD/plugin/pkg/scheduler/generic_scheduler.go)
## Scheduler extensibility
The scheduler is extensible: the cluster administrator can choose which of the pre-defined
scheduling policies to apply, and can add new ones. The built-in predicates and priorities are
defined in [plugin/pkg/scheduler/algorithm/predicates/predicates.go](../../plugin/pkg/scheduler/algorithm/predicates/predicates.go) and
[plugin/pkg/scheduler/algorithm/priorities/priorities.go](../../plugin/pkg/scheduler/algorithm/priorities/priorities.go), respectively.
defined in [plugin/pkg/scheduler/algorithm/predicates/predicates.go](http://releases.k8s.io/HEAD/plugin/pkg/scheduler/algorithm/predicates/predicates.go) and
[plugin/pkg/scheduler/algorithm/priorities/priorities.go](http://releases.k8s.io/HEAD/plugin/pkg/scheduler/algorithm/priorities/priorities.go), respectively.
The policies that are applied when scheduling can be chosen in one of two ways. Normally,
the policies used are selected by the functions `defaultPredicates()` and `defaultPriorities()` in
[plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go](../../plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go).
[plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go](http://releases.k8s.io/HEAD/plugin/pkg/scheduler/algorithmprovider/defaults/defaults.go).
However, the choice of policies
can be overridden by passing the command-line flag `--policy-config-file` to the scheduler, pointing to a JSON
file specifying which scheduling policies to use. See
[examples/scheduler-policy-config.json](../../examples/scheduler-policy-config.json) for an example
config file. (Note that the config file format is versioned; the API is defined in
[plugin/pkg/scheduler/api](../../plugin/pkg/scheduler/api/)).
[plugin/pkg/scheduler/api](http://releases.k8s.io/HEAD/plugin/pkg/scheduler/api/)).
Thus to add a new scheduling policy, you should modify predicates.go or priorities.go,
and either register the policy in `defaultPredicates()` or `defaultPriorities()`, or use a policy config file.
## Exploring the code
If you want to get a global picture of how the scheduler works, you can start in
[plugin/cmd/kube-scheduler/app/server.go](../../plugin/cmd/kube-scheduler/app/server.go)
[plugin/cmd/kube-scheduler/app/server.go](http://releases.k8s.io/HEAD/plugin/cmd/kube-scheduler/app/server.go)
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