I have a simple setup where a framework runs with a role, and some
resources are reserved in cluster for that role.
The resource offers arrive at the framework as a list of two resource
sets: one general (cpus(*)), etc) and one specific for the role
(cpus("role1"), etc).
So far so good. If two tasks are launched, each with one of the two
resources, things work.
But problems start when I need to launch multiple smaller tasks (with a
total resource consumption equal to the offered). I run this by creating
resource objects, and attaching them to tasks, using calls from the
standard Mesos samples (python):
task = mesos_pb2.TaskInfo()
cpus = task.resources.add()
cpus.name = "cpus"
cpus.scalar.value = TASK_CPUS
checking that total doesnt surpass the offered resources. This starts
fine, but soon I get TASK_ERROR messages, due to Master validator finding
that more resources are requested by tasks than available in the offer.
This obviously happens because all tasks resources, as defined above, come
with (*) role, while the offer resources are split between "*" and "role1"
! Ok, then I assign a role to task resources, by adding
cpus.role = "role1"
But this fails again, and for the same reason..
Shouldn't this work differently? When a resource offer is received
framework with a "role1", why should it care which part is 'unreserved'
and which part is reserved to "role1"? When a task launch request is
received by the master, from a framework with a role, why can't it check
only the total resource amount, instead of treating unreserved and
reserved resources separately? They are reserved for this role anyway.. Or
I'm missing something?
Regards,
Gidon
