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https://issues.apache.org/jira/browse/MESOS-5377?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15283837#comment-15283837
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Qian Zhang commented on MESOS-5377:
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Can we introduce weight for each resource allocated by Mesos master?
{{Each resource's weight = the number of agents have this resource / the number
of total agents}}
And then when we calculate the resource share for each role/framework in DRF
sorter, we can take this weight into account: {{resource share = resource
weight * (allocation / total)}}. So for the example in the description of this
ticket, the weight of GPU will be 0.001, and the GPU share of the role which
consumes the only 1 GPU will be 0.001 rather than 1. This can be the default
behavior and we may consider to introduce a flag to Mesos master with which
operator can explicitly set weight for each resource to override the default
way to calculate the resource's weight.
> Improve DRF behavior with scarce resources.
> -------------------------------------------
>
> Key: MESOS-5377
> URL: https://issues.apache.org/jira/browse/MESOS-5377
> Project: Mesos
> Issue Type: Epic
> Components: allocation
> Reporter: Benjamin Mahler
>
> The allocator currently uses the notion of Weighted [Dominant Resource
> Fairness|https://www.cs.berkeley.edu/~alig/papers/drf.pdf] (WDRF) to
> establish a linear notion of fairness across allocation roles.
> DRF behaves well for resources that are present within each machine in a
> cluster (e.g. CPUs, memory, disk). However, some resources (e.g. GPUs) are
> only present on a subset of machines in the cluster.
> Consider the behavior when there are the following agents in a cluster:
> 1000 agents with (cpus:4,mem:1024,disk:1024)
> 1 agent with (gpus:1,cpus:4,mem:1024,disk:1024)
> If a role wishes to use both GPU and non-GPU resources for tasks, consuming 1
> GPU will lead DRF to consider the role to have a 100% share of the cluster,
> since it consumes 100% of the GPUs in the cluster. This framework will then
> not receive any other offers.
> Among possible improvements, fairness can have understanding of resource
> packages. In a sense there is 1 GPU package that is competed on and 1000
> non-GPU packages competed on, and ideally a role's consumption of the single
> GPU package does not have a large effect on the role's access to the other
> 1000 non-GPU packages.
> In the interim, we should consider having a recommended way to deal with
> scarce resources in the current model.
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