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Ship it! Ship It! - Guangya Liu On 九月 4, 2015, 11:19 p.m., Michael Park wrote: > > ----------------------------------------------------------- > This is an automatically generated e-mail. To reply, visit: > https://reviews.apache.org/r/35702/ > ----------------------------------------------------------- > > (Updated 九月 4, 2015, 11:19 p.m.) > > > Review request for mesos, Adam B, Benjamin Hindman, Ben Mahler, Jie Yu, Joris > Van Remoortere, and Vinod Kone. > > > Bugs: MESOS-2600 > https://issues.apache.org/jira/browse/MESOS-2600 > > > Repository: mesos > > > Description > ------- > > This involved a lot more challenges than I anticipated, I've captured the > various approaches and limitations and deal-breakers of those approaches > here: [Master Endpoint Implementation > Challenges](https://docs.google.com/document/d/1cwVz4aKiCYP9Y4MOwHYZkyaiuEv7fArCye-vPvB2lAI/edit#) > > Key points: > > * This is a stop-gap solution until we shift the offer creation/management > logic from the master to the allocator. > * `updateAvailable` and `updateSlave` are kept separate because > (1) `updateAvailable` is allowed to fail whereas `updateSlave` must not. > (2) `updateAvailable` returns a `Future` whereas `updateSlave` does not. > (3) `updateAvailable` never leaves the allocator in an over-allocated state > and must not, whereas `updateSlave` does, and can. > * The algorithm: > * Initially, the master pessimistically assume that what seems like > "available" resources will be gone. > This is due to the race between the allocator scheduling an `allocate` > call to itself vs master's > `allocator->updateAvailable` invocation. > As such, we first try to satisfy the request only with the offered > resources. > * We greedily rescind one offer at a time until we've rescinded > sufficiently many offers. > IMPORTANT: We perform `recoverResources(..., Filters())` which has a > default `refuse_sec` of 5 seconds, > rather than `recoverResources(..., None())` so that we can virtually > always win the race against `allocate`. > In the rare case that we do lose, no disaster occurs. We simply fail to > satisfy the request. > * If we still don't have enough resources after resciding all offers, be > semi-optimistic and forward the > request to the allocator since there may be available resources to > satisfy the request. > * If the allocator returns a failure, report the error to the user with > `Conflict`. > > This approach is clearly not ideal, since we would prefer to rescind as > little offers as possible. > > > Diffs > ----- > > src/master/http.cpp 94e97a2898106579434e8cdec04b7b0e130a810e > src/master/master.hpp e1331851c19e3372a4a525dcfd7ba2a01c3e97a6 > src/master/master.cpp 5589eca4317b597de509f3387cfc349083b361ac > src/master/validation.hpp 43b8d84556e7f0a891dddf6185bbce7ca50b360a > src/master/validation.cpp ffb7bf07b8a40d6e14f922eabcf46045462498b5 > > Diff: https://reviews.apache.org/r/35702/diff/ > > > Testing > ------- > > `make check` > > > Thanks, > > Michael Park > >
