slurm cannot oversubscribe CPUs

limit cluster tests to 2, since that's what we get on github actions

Author: minrk

ci/slurm/slurm.conf

@@ -47,5 +47,7 @@ SlurmdLogFile=/var/log/slurm-llnl/slurmd.log
 #
 #
 # COMPUTE NODES
-NodeName=localhost NodeHostName=localhost NodeAddr=127.0.0.1 CPUs=3 State=UNKNOWN
+# Note: CPUs apparently cannot be oversubscribed
+# this can only run where at least 2 CPUs are available
+NodeName=localhost NodeHostName=localhost NodeAddr=127.0.0.1 CPUs=2 State=UNKNOWN
 PartitionName=part Nodes=localhost Default=YES MaxTime=INFINITE State=UP OverSubscribe=YES

ipyparallel/tests/test_cluster.py

@@ -1,6 +1,5 @@
 import asyncio
 import os
-import shutil
 import signal
 import sys
 import time
@@ -84,7 +83,7 @@ async def test_start_stop_engines(Cluster, engine_launcher_class):
     cluster = Cluster(engine_launcher_class=engine_launcher_class)
     await cluster.start_controller()
 
-    n = 3
+    n = 2
     engine_set_id = await cluster.start_engines(n)
     assert engine_set_id in cluster._engine_sets
     engine_set = cluster._engine_sets[engine_set_id]
@@ -123,10 +122,10 @@ async def test_start_stop_cluster(Cluster, engine_launcher_class):
 async def test_signal_engines(request, Cluster, engine_launcher_class):
     cluster = Cluster(engine_launcher_class=engine_launcher_class)
     await cluster.start_controller()
-    engine_set_id = await cluster.start_engines(n=3)
+    engine_set_id = await cluster.start_engines(n=2)
     rc = await cluster.connect_client()
     request.addfinalizer(rc.close)
-    rc.wait_for_engines(3)
+    rc.wait_for_engines(2)
     # seems to be a problem if we start too soon...
     await asyncio.sleep(1)
     # ensure responsive
@@ -153,7 +152,7 @@ async def test_signal_engines(request, Cluster, engine_launcher_class):
 
 
 async def test_restart_engines(Cluster, engine_launcher_class):
-    n = 3
+    n = 2
     async with Cluster(engine_launcher_class=engine_launcher_class, n=n) as rc:
         cluster = rc.cluster
         engine_set_id = next(iter(cluster._engine_sets))