Add config modules for controlling IBM PowerVM RMC. (#584)

Reliable Scalable Cluster Technology (RSCT) is a set of software
components that together provide a comprehensive clustering
environment(RAS features) for IBM PowerVM based virtual machines. RSCT
includes the Resource Monitoring and Control (RMC) subsystem. RMC is a
generalized framework used for managing, monitoring, and manipulating
resources. RMC runs as a daemon process on individual machines and needs
creation of unique node id and restarts during VM boot.

LP: #1895979

Co-authored-by: Scott Moser <smoser@brickies.net>

1 files changed, 143 insertions, 0 deletions

diff --git a/cloudinit/config/cc_reset_rmc.py b/cloudinit/config/cc_reset_rmc.py
new file mode 100644
index 00000000..1cd72774
--- /dev/null
+++ b/cloudinit/config/cc_reset_rmc.py
@@ -0,0 +1,143 @@
+# (c) Copyright IBM Corp. 2020 All Rights Reserved
+#
+# Author: Aman Kumar Sinha <amansi26@in.ibm.com>
+#
+# This file is part of cloud-init. See LICENSE file for license information.
+
+
+"""
+Reset RMC
+------------
+**Summary:** reset rsct node id
+
+Reset RMC module is IBM PowerVM Hypervisor specific
+
+Reliable Scalable Cluster Technology (RSCT) is a set of software components,
+that  together provide a comprehensive clustering environment (RAS features)
+for IBM PowerVM based virtual machines. RSCT includes the Resource monitoring
+and control (RMC) subsystem. RMC is a generalized framework used for managing,
+monitoring, and manipulating resources. RMC runs as a daemon process on
+individual machines and needs creation of unique node id and restarts
+during VM boot.
+More details refer
+https://www.ibm.com/support/knowledgecenter/en/SGVKBA_3.2/admin/bl503_ovrv.htm
+
+This module handles
+- creation of the unique RSCT node id to every instance/virtual machine
+  and ensure once set, it isn't changed subsequently by cloud-init.
+  In order to do so, it restarts RSCT service.
+
+Prerequisite of using this module is to install RSCT packages.
+
+**Internal name:** ``cc_reset_rmc``
+
+**Module frequency:** per instance
+
+**Supported distros:** rhel, sles and ubuntu
+
+"""
+import os
+
+from cloudinit import log as logging
+from cloudinit.settings import PER_INSTANCE
+from cloudinit import util
+from cloudinit import subp
+
+frequency = PER_INSTANCE
+
+# RMCCTRL is expected to be in system PATH (/opt/rsct/bin)
+# The symlink for RMCCTRL and RECFGCT are
+# /usr/sbin/rsct/bin/rmcctrl and
+# /usr/sbin/rsct/install/bin/recfgct respectively.
+RSCT_PATH = '/opt/rsct/install/bin'
+RMCCTRL = 'rmcctrl'
+RECFGCT = 'recfgct'
+
+LOG = logging.getLogger(__name__)
+
+NODE_ID_FILE = '/etc/ct_node_id'
+
+
+def handle(name, _cfg, cloud, _log, _args):
+    # Ensuring node id has to be generated only once during first boot
+    if cloud.datasource.platform_type == 'none':
+        LOG.debug('Skipping creation of new ct_node_id node')
+        return
+
+    if not os.path.isdir(RSCT_PATH):
+        LOG.debug("module disabled, RSCT_PATH not present")
+        return
+
+    orig_path = os.environ.get('PATH')
+    try:
+        add_path(orig_path)
+        reset_rmc()
+    finally:
+        if orig_path:
+            os.environ['PATH'] = orig_path
+        else:
+            del os.environ['PATH']
+
+
+def reconfigure_rsct_subsystems():
+    # Reconfigure the RSCT subsystems, which includes removing all RSCT data
+    # under the /var/ct directory, generating a new node ID, and making it
+    # appear as if the RSCT components were just installed
+    try:
+        out = subp.subp([RECFGCT])[0]
+        LOG.debug(out.strip())
+        return out
+    except subp.ProcessExecutionError:
+        util.logexc(LOG, 'Failed to reconfigure the RSCT subsystems.')
+        raise
+
+
+def get_node_id():
+    try:
+        fp = util.load_file(NODE_ID_FILE)
+        node_id = fp.split('\n')[0]
+        return node_id
+    except Exception:
+        util.logexc(LOG, 'Failed to get node ID from file %s.' % NODE_ID_FILE)
+        raise
+
+
+def add_path(orig_path):
+    # Adding the RSCT_PATH to env standard path
+    # So thet cloud init automatically find and
+    # run RECFGCT to create new node_id.
+    suff = ":" + orig_path if orig_path else ""
+    os.environ['PATH'] = RSCT_PATH + suff
+    return os.environ['PATH']
+
+
+def rmcctrl():
+    # Stop the RMC subsystem and all resource managers so that we can make
+    # some changes to it
+    try:
+        return subp.subp([RMCCTRL, '-z'])
+    except Exception:
+        util.logexc(LOG, 'Failed to stop the RMC subsystem.')
+        raise
+
+
+def reset_rmc():
+    LOG.debug('Attempting to reset RMC.')
+
+    node_id_before = get_node_id()
+    LOG.debug('Node ID at beginning of module: %s', node_id_before)
+
+    # Stop the RMC subsystem and all resource managers so that we can make
+    # some changes to it
+    rmcctrl()
+    reconfigure_rsct_subsystems()
+
+    node_id_after = get_node_id()
+    LOG.debug('Node ID at end of module: %s', node_id_after)
+
+    # Check if new node ID is generated or not
+    # by comparing old and new node ID
+    if node_id_after == node_id_before:
+        msg = 'New node ID did not get generated.'
+        LOG.error(msg)
+        raise Exception(msg)