The differences of PriorityClass between volcano and default scheduler?

[zhucan]

Please provide an in-depth description of the question you have:

for k8s default scheduler: An example use case is for data science workloads. A user may submit a job that they want to be prioritized above other workloads, but do not wish to discard existing work by preempting running pods. The high priority job with preemptionPolicy: Never will be scheduled ahead of other queued pods, as soon as sufficient cluster resources "naturally" become free.

but I don't know clear about the volcano.

What do you think about this question?: if the preemptionPolicy is Never, the high priority jobs will be scheduler always before the low priority jobs or normal jobs?

Environment:

• Volcano Version:
• Kubernetes version (use kubectl version):
• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

[Monokaix]

The priorityClass in volcano also play a role in scheduling and preemption，and job with higher priority can preempt lower job，and also schedule first before lower priority job，but a little difference is that volcano will also consider job's queue priority.

[zhucan]

so, The high priority job with "preemptionPolicy: Never" will not be scheduled ahead of other queued pods? @Monokaix

[Monokaix]

so, The high priority job with "preemptionPolicy: Never" will not be scheduled ahead of other queued pods? @Monokaix

It depends, queue's order is determined by share value, if a queue has a lower share value, jobs in this queue will schedule first. Refer to https://volcano.sh/zh/docs/v1-8-2/plugins/#drf for more detail.

[JesseStutler]

@zhucan Right now volcano hasn't support preemptionPolicy yet, we prepare to implement it, see this: #3642

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