Hi Li, (1) I have the impression that Mesos supports sending the same offer to > multiple frameworks at the same time but couldn't find the code does that. > Is this supported now or will it be supported in the future? >
Yes, the semantics include the ability to send the same offer to multiple frameworks! This is currently not implemented, but you should assume this can/will happen in the future. For those of you that have read the the Omega paper, you'll notice that the current offer implementation is why Mesos was described as "pessimistic concurrency". That being said, once we starting sending "overlapping" offers we'll move more into the "optimistic concurrency" space. In fact, the Mesos allocator has the ability to travel the spectrum of pessimistic to optimistic very easily! In the extreme, we can send all available resources as offers to all frameworks, thus being completely optimistic! > (2) I've noticed if a framework gets a resource offer but doesn't reply, > the same resource will not be offered to other frameworks ever. What's the > suggested way of dealing with the situation where a framework holds a offer > and doesn't do anything? > Restarting a master will "kill" all old offers. Ideally the framework will decline offers that it's not using. It's very straightforward to put timeouts on offers that the allocator sends out too, see https://issues.apache.org/jira/browse/MESOS-186 (and we'd love some contributions if you're looking for something to work on!). Ben. > > Thanks, > Li >
