For (3), actually the answer is yes. The API exposes a mechanism for schedulers to explicitly request resources. However, it's not implemented in the allocator as all schedulers have just relied on the master sending offers periodically, for now.
On Sat, Mar 14, 2015 at 6:36 AM, Jörg Schad <[email protected]> wrote: > Hi, > I tried to answer your questions inline below: > Overall I would recommend you to have a look at the following paper > explaining some of the background of scheduling and architecture : > http://mesos.berkeley.edu/mesos_tech_report.pdf and > https://www.cs.berkeley.edu/~alig/papers/drf.pdf. > > Regards, > Joerg > > On Sat, Mar 14, 2015 at 2:15 PM, Kenneth Hui <[email protected]> wrote: > >> All, >> >> I am new to the Mesos project and have been reading up on the technology >> and have questions for which I have not been able to find answers. I would >> appreciate any answers to the questions below or links to where I can find >> the answers myself. >> >> 1. How does the Master determine the order in which it offers >> resources? Is it a simple round-robin, taking into account filters, or is >> there a algorithm that is followed? >> >> This is determined by the allocator where the standard is the Dominant > Resource Fairness explained in the second paper above. > For more details see here > http://mesos.apache.org/documentation/latest/allocation-module/ > > > >> >> 1. Are there any mechanisms where a framework can initiate an offer >> request so that it receives the next resource offer or do frameworks >> always >> have to wait for the Master to decide the order of resource offers? >> >> Framework (Scheduler) have to wait for the Master to offer them > ressources. See links in above answer for more details. > > >> >> 1. When a task is executed across a cluster, does the Master always >> try to distribute the task across all slave nodes with sufficient >> available >> resources or would it ever run all task on a single node in the cluster if >> it has sufficient resources? >> >> The nodes announces free resources which the master then offers to the > registered framework. So it depends on how many offers the framework(s) > accept. > > > >> >> 1. How does Mesos respond if all its slave nodes run out of physical >> resources and are unable to offer sufficient resources for an extended >> period of time? >> >> As long as the slave (process) is reachable from the master this is ok as > the node is participating in the cluster (with 'old' jobs). > > > >> >> Thank you for your help. >> >> >> -- >> Ken >> >> >> >
