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Bharath Ravi Kumar commented on MESOS-1607: ------------------------------------------- Is there a particular milestone that this feature is being targeted for (tentatively)? Would be useful to know that. Thanks. > Introduce optimistic offers. > ---------------------------- > > Key: MESOS-1607 > URL: https://issues.apache.org/jira/browse/MESOS-1607 > Project: Mesos > Issue Type: Epic > Components: allocation, framework, master > Reporter: Benjamin Hindman > Assignee: Artem Harutyunyan > Labels: mesosphere > Attachments: optimisitic-offers.pdf > > > *Background* > The current implementation of resource offers only enable a single framework > scheduler to make scheduling decisions for some available resources at a > time. In some circumstances, this is good, i.e., when we don't want other > framework schedulers to have access to some resources. However, in other > circumstances, there are advantages to letting multiple framework schedulers > attempt to make scheduling decisions for the _same_ allocation of resources > in parallel. > If you think about this from a "concurrency control" perspective, the current > implementation of resource offers is _pessimistic_, the resources contained > within an offer are _locked_ until the framework scheduler that they were > offered to launches tasks with them or declines them. In addition to making > pessimistic offers we'd like to give out _optimistic_ offers, where the same > resources are offered to multiple framework schedulers at the same time, and > framework schedulers "compete" for those resources on a > first-come-first-serve basis (i.e., the first to launch a task "wins"). We've > always reserved the right to rescind resource offers using the 'rescind' > primitive in the API, and a framework scheduler should be prepared to launch > a task and have those tasks go lost because another framework already started > to use those resources. > *Feature* > We plan to take a step towards optimistic offers, by introducing primitives > that allow resources to be offered to multiple frameworks at once. At first, > we will use these primitives to optimistically allocate resources that are > reserved for a particular framework/role but have not been allocated by that > framework/role. > The work with optimistic offers will closely resemble the existing > oversubscription feature. Optimistically offered resources are likely to be > considered "revocable resources" (the concept that using resources not > reserved for you means you might get those resources revoked). In effect, we > can may create something like a "spot" market for unused resources, driving > up utilization by letting frameworks that are willing to use revocable > resources run tasks. > *Future Work* > This ticket tracks the introduction of some aspects of optimistic offers. > Taken to the limit, one could imagine always making optimistic resource > offers. This bears a striking resemblance with the Google Omega model (an > isomorphism even). However, being able to configure what resources should be > allocated optimistically and what resources should be allocated > pessimistically gives even more control to a datacenter/cluster operator that > might want to, for example, never let multiple frameworks (roles) compete for > some set of resources. -- This message was sent by Atlassian JIRA (v6.3.4#6332)