PP-1281: New decorator in PTL using which user can provide cluster information required for a test.

Description:
There is a need to have a decorator through which user can specify cluster information like number of servers, moms, comms and clients etc. required for a particular test to run.

Forum: http://community.pbspro.org/t/pp-1281-new-decorator-in-ptl-using-which-user-can-provide-cluster-information-required-for-a-test/1050

Ticket: https://openpbs.atlassian.net/browse/PP-1281

Interface: @requirements(num_servers=<number_of_servers>,num_moms=<number_of_moms>,num_comms=<number_of_comms>,num_clients=<number_of_clients>,no_mom_on_server=<Boolean>,no_comm_on_server=<Boolean>, no_comm_on_mom=<Boolean>)
Visibility: Public
Change Control: Stable
Synopsis: New interface to provide the cluster information required for particular testcase/testsuite.
Details:

• @requirements decorator is used to specify the cluster requirements for a given test case to run. It can be specified at test case or test suite level. This decorator function is called before the test setup of the test case runs. 

• This requirements decorator data is validated against the data passed to the param list (-p and --param-file) of pbs_benchpress

• In case where the requirements do not match with the data passed to param list of pbs_benchpress, the test execution is skipped using SkipTest().

• In case where the requirements match with the data passed to param list of pbs_benchpress, the test execution is continued.

• Keys and default values for decorator parameters are: 

  • num_servers=1

  • num_moms=1

  • num_comms=1

  • num_clients=1

  • no_mom_on_server=False (Which will imply that Server host should have a mom on it )

  • no_comm_on_server=False (Which will imply that Server host should have a comm on it)

  • no_comm_on_mom=True (Which will imply that comm should be on different host than mom i.e. a mom on non-server host)

This means with default configuration, test will intend to run on a single node.

• The test case level values of requirements decorator override the test suite level requirements values

• Currently this data including the flags no_mom_on_server, no_comm_on_server & no_comm_on_mom are applicable to all the servers in case of multiple server setup

Examples: 

• Case 1- Default requirements : Test needs a single Node with all daemons on same host.

• Case 2- Test requires 4 moms and 2 comms.

  • With 1 mom and 1 comm on server node: @requirements(num_moms=4, num_comms=2)

    • By default 'no_mom_on_server' and 'no_comm_on_server' are False and no_comm_on_mom is true, so cluster will consist of total 5 nodes which will look like:

      • Node1: Server, Sched, Mom, Comm

      • Node2: Mom

      • Node3: Mom

      • Node4: Mom

      • Node5: Comm

  • With no mom and comm on server node: @requirements(num_moms=4, num_comms=2, no_mom_on_server=True, no_comm_on_server=True)

    • By default no_comm_on_mom is true, so cluster will consist of total 7 nodes which will look like:

      • Node1: Server, Sched

      • Node2: Mom

      • Node3: Mom

      • Node4: Mom

      • Node5: Mom

      • Node6: Comm

      • Node7: Comm

  • With no mom and comm on server node and comm on mom node: @requirements(num_moms=4, num_comms=2, no_mom_on_server=True, no_comm_on_server=True, no_comm_on_mom=False)

    • Cluster will consist of total 5 nodes which will look like:

      • Node1: Server, Sched

      • Node2: Mom, Comm

      • Node3: Mom, Comm

      • Node4: Mom

      • Node5: Mom

• Case 3 - Test requires 3 moms without comms on the mom nodes:

  • With 1 mom and 1 comm on server node: @requirements(num_moms=3)

    • Cluster will consist of total 3 nodes

      • Node 1: server,sched,mom1 & comm

      • Node 2: mom2

      • Node 3: mom3

Note: Currently PTL supports specification of a single host for "client" parameter in pbs_benchpress command, i.e. name of the host on which the PBS client commands are to be run from. Hence, the specification of requirement of multiple clients for a given test case can be completely functional only after implementation of ticket PP-1327. As of now test execution of any test case that specifies num_clients as greater than one will be skipped.

Interface: PTLTestInfo._gen_ts_tree()
Visibility: Public
Change Control: Stable
Synopsis: Updating existing interface to add requirements information to testsuite's json tree, provided by @requirements decorator. Tools which run PTL, can make use of this information to form a multinode cluster.
Details:

• json test suite tree generated with info option of pbs_benchpress along with --gen-ts-tree (using PTLTestInfo._gen_ts_tree() method) will now include the requirements data mentioned for each test case

• this data is populated as value for a new key called 'requirements' under test case name hierarchy in the generated json tree

• for test cases without requirements decorator, default values of requirements are specified

Example: json tree of a test case with @requirements(num_moms=4) inside a test suite with @requirements(num_comms=2) at test suite level will look as below: