YuniKorn Concepts: Difference between revisions

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* [[YuniKorn#Subjects| YuniKorn]]
* [[YuniKorn#Subjects| YuniKorn]]


=Application=
=YuniKorn Core=
==Application ID==
{{Internal|YuniKorn Core Concepts|YuniKorn Core Concepts}}


=Plugin Mode=
=Kuberentes Implementation=
 
* A namespace can have a "queue" if annotated with "yunikorn.apache.org/queue". A namespace can have a "parent queue" is annotated with "yunikorn.apache.org/parentqueue".
=Resource Manager (RM)=
* An allocation can be in one of two states ("Pending" and "In-Progress"). A pending allocation is one which has been decided upon by YuniKorn but has not yet been communicated to the default scheduler via PreFilter()/Filter(). Once PreFilter()/Filter() pass, the allocation transitions to "In-Progress" to signify that the default scheduler is responsible for fulfilling the allocation. Once PostBind() is called in the plugin to signify completion of the allocation, it is removed.
 
* When a new pod annotated with <code>schedulerName: yunikorn</code> needs scheduling, the API server (admission controller (?)) calls the "admission-webhook.yunikorn.mutate-pods" webhook with a POST https://yunikorn-admission-controller-service.yunikorn.svc:443/mutate?timeout=10s. Service "yunikorn-admission-controller-service". When running locally, the service does not get deployed, yet the pods get scheduled. This is how: there's a Kubernetes mechanism involving "informers" that periodically updates the state of the resources is interested in. There are "update", "add" and "delete" notifications. When a new pod shows up, <code>general.Manager.AddPod()</code> is invoked, which creates and Application and Task using the pod metadata → <code>PodEventHandler.addPod()</code> → <code>cache.Context.AddApplication()</code>. At the same time, there's the main KubernetesShim scheduling loop that finds the new application and so the scheduling process begins.
YuniKorn communicates with various implementation of resource management systems (Kubernetes, YARN) via a standard interface defined in the <code>[[YuniKorn_Development#yunikorn-scheduler-interface|yunikorn-scheduler-interface]]</code> package.
 
=Allocation=

Latest revision as of 22:06, 18 January 2024

Internal

YuniKorn Core

YuniKorn Core Concepts

Kuberentes Implementation

  • A namespace can have a "queue" if annotated with "yunikorn.apache.org/queue". A namespace can have a "parent queue" is annotated with "yunikorn.apache.org/parentqueue".
  • An allocation can be in one of two states ("Pending" and "In-Progress"). A pending allocation is one which has been decided upon by YuniKorn but has not yet been communicated to the default scheduler via PreFilter()/Filter(). Once PreFilter()/Filter() pass, the allocation transitions to "In-Progress" to signify that the default scheduler is responsible for fulfilling the allocation. Once PostBind() is called in the plugin to signify completion of the allocation, it is removed.
  • When a new pod annotated with schedulerName: yunikorn needs scheduling, the API server (admission controller (?)) calls the "admission-webhook.yunikorn.mutate-pods" webhook with a POST https://yunikorn-admission-controller-service.yunikorn.svc:443/mutate?timeout=10s. Service "yunikorn-admission-controller-service". When running locally, the service does not get deployed, yet the pods get scheduled. This is how: there's a Kubernetes mechanism involving "informers" that periodically updates the state of the resources is interested in. There are "update", "add" and "delete" notifications. When a new pod shows up, general.Manager.AddPod() is invoked, which creates and Application and Task using the pod metadata → PodEventHandler.addPod()cache.Context.AddApplication(). At the same time, there's the main KubernetesShim scheduling loop that finds the new application and so the scheduling process begins.