pmda/rds: Introduce new PMDA for RDS

[Hannibal404]

This change adds a new PMDA (Performance Metrics Domain Agent) for Reliable Datagram Sockets (RDS). It exports key metrics including connection information, socket and connection statistics, and details of send, receive, and retransmit queues for performance analysis using Performance Co-Pilot (PCP).

This PMDA is intended to aid in diagnosing network-related issues on systems using RDS over Infiniband or TCP.

Replaces #2230

[natoscott]

Install fails for me after building rpm packages with:

[pcpqa@fedora rds]$ sudo ./Install 
Traceback (most recent call last):
  File "/var/lib/pcp/pmdas/rds/pmdards.python", line 25, in <module>
    from modules.rds_ping import rds_ping_all_avlbl_dest
ModuleNotFoundError: No module named 'modules.rds_ping'

I expect it relates to the .python file extensions, and the more dynamic import mechanism used by pmdabcc might be more what you're after here.

Unrelated to this, the new QA test .out file contains several errors as well that shouldn't be there (relating to 'unknown metric name') - but, it fails with the Install for me so I've not been able to observe that second issue locally to advise further (its definitely wrong, I just don't know why).

[Hannibal404]

Added simlinks for the modules files to fix the errors.

The QA output had unknown metrics errors due to IB specific metrics on a machine without infiniband. Updated.

[natoscott]

@Hannibal404 thanks for the updates, I'm still seeing issues though. The test fails because rds Install fails similarly to previously...

[pcpqa@fedora rds]$ sudo ./Install 
Traceback (most recent call last):
  File "/var/lib/pcp/pmdas/rds/pmdards.python", line 50, in <module>
    from modules.rds_ping import rds_ping_all_avlbl_dest
ModuleNotFoundError: No module named 'modules.rds_ping'
Arrgh! failed to create /var/lib/pcp/pmdas/rds/domain.h.python from /var/lib/pcp/pmdas/rds/pmdards.python

I think you may need something more like this code from pmdabcc:

    def init_modules(self):
        """ Initialize modules """
        self.log("Initializing modules:")

        # For packaging, allow both .python and .py suffixed files
        cwd = os.getcwd()
        pmdadir = PCP.pmGetConfig('PCP_PMDASADM_DIR') + '/' + self.read_name()
        for root, _, filenames in os.walk(pmdadir):
            os.chdir(root)
            for filename in fnmatch.filter(filenames, '*.python'):
                if filename in ('pmdabcc.python', 'domain.h.python', 'pmns.python'):
                    continue
                pyf = filename[:-4]
                if not os.path.exists(pyf):
                    os.symlink(filename, pyf)
            os.chdir(pmdadir)
        os.chdir(cwd)

        import pmdautil # pylint: disable=import-outside-toplevel
        self.proc_helper = pmdautil.ProcMon(self.log, self.err)
        for module in self.modules:
            self.log(module)
            try:
                mod = importlib.import_module('modules.%s' % self.modules[module][MODULE])