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https://issues.apache.org/jira/browse/MESOS-8626?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Benjamin Bannier reassigned MESOS-8626:
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Assignee: Benjamin Bannier
> The 'allocatable' check in the allocator is problematic with multi-role
> frameworks
> ----------------------------------------------------------------------------------
>
> Key: MESOS-8626
> URL: https://issues.apache.org/jira/browse/MESOS-8626
> Project: Mesos
> Issue Type: Bug
> Components: allocation
> Affects Versions: 1.3.2, 1.4.1, 1.5.0
> Reporter: Jie Yu
> Assignee: Benjamin Bannier
> Priority: Major
> Labels: mesosphere, multitenancy
>
> The
> [allocatable|https://github.com/apache/mesos/blob/1.5.x/src/master/allocator/mesos/hierarchical.cpp#L2471-L2479]
> check in the allocator (shown below) was originally introduced to help
> alleviate the situation where a framework receives only disk, but not
> cpu/memory, thus cannot launch a task.
> {code}
> bool HierarchicalAllocatorProcess::allocatable(
> const Resources& resources)
> {
> Option<double> cpus = resources.cpus();
> Option<Bytes> mem = resources.mem();
> return (cpus.isSome() && cpus.get() >= MIN_CPUS) ||
> (mem.isSome() && mem.get() >= MIN_MEM);
> }
> {code}
> When we introduce multi-role capability to the frameworks, this check makes
> less sense now. For instance, consider the following case:
> 1) There is a single agent and a single framework in the cluster
> 2) The agent has cpu/memory reserved to role A, and disk reserved to B
> 3) The framework subscribes to both role A and role B
> 4) The framework expects that it'll receive an offer containing the resources
> on the agent
> 5) However, the framework receives no disk resources due to the following
> [code|https://github.com/apache/mesos/blob/1.5.x/src/master/allocator/mesos/hierarchical.cpp#L2078-L2100].
> This is counter intuitive.
> {code}
> void HierarchicalAllocatorProcess::__allocate()
> {
> ...
> Resources resources = available.allocatableTo(role);
> if (!allocatable(resources)) {
> break;
> }
> ...
> }
> bool Resources::isAllocatableTo(
> const Resource& resource,
> const std::string& role)
> {
> CHECK(!resource.has_role()) << resource;
> CHECK(!resource.has_reservation()) << resource;
> return isUnreserved(resource) ||
> role == reservationRole(resource) ||
> roles::isStrictSubroleOf(role, reservationRole(resource));
> }
> {code}
> Two comments:
> 1) If `allocatable` check is still necessary (see MESOS-7398)?
> 2) If we want to keep `allocatable` check for the original purpose, we should
> do that based on framework not role, given that a framework can subscribe to
> multiple roles now?
> Some related JIRAs:
> MESOS-1688
> MESOS-7398
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