The conditional around some of the rescheduling tests was backwards, where we
were waiting for allocations to be rescheduled but testing for a count of
0. The test was passing but flaky because if the check happened quickly enough
before the scheduler rescheduled the allocations, it would pass.
The CLI helpers in the rescheduling test were intended for shared use, but
until some other tests were written we didn't want to waste time making them
generic. This changeset refactors them and adds some new helpers associated
with the node drain tests (under separate PR).
The rescheduling test workloads were created before we had Windows targets in
the E2E nightly run. When these were recently ported to the e2e framework they
were missing the constraint to Linux machines.
Also added a little extra time to polling to avoid some flakiness on the first
run, and a minor readability adjustment to the job names.
Ports the rescheduling tests (which aren't running in CI) into the current
test framework so that they're run on nightly, and exercises the new CLI
helpers.
Remove the NOMAD_TEST_RKT flag as a guard for rkt tests. Still require
Linux, root, and rkt to be installed. Only check for rkt installation
once in hopes of speeding up rkt tests a bit.
