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, 159 insertions, 0 deletions

diff --git a/cloudinit/config/cc_refresh_rmc_and_interface.py b/cloudinit/config/cc_refresh_rmc_and_interface.py
new file mode 100644
index 00000000..146758ad
--- /dev/null
+++ b/cloudinit/config/cc_refresh_rmc_and_interface.py
@@ -0,0 +1,159 @@
+# (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.
+
+"""
+Refresh IPv6 interface and RMC
+------------------------------
+**Summary:** Ensure Network Manager is not managing IPv6 interface
+
+This 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
+- Refreshing RMC
+- Disabling NetworkManager from handling IPv6 interface, as IPv6 interface
+  is used for communication between RMC daemon and PowerVM hypervisor.
+
+**Internal name:** ``cc_refresh_rmc_and_interface``
+
+**Module frequency:** per always
+
+**Supported distros:** RHEL
+
+"""
+
+from cloudinit import log as logging
+from cloudinit.settings import PER_ALWAYS
+from cloudinit import util
+from cloudinit import subp
+from cloudinit import netinfo
+
+import errno
+
+frequency = PER_ALWAYS
+
+LOG = logging.getLogger(__name__)
+# Ensure that /opt/rsct/bin has been added to standard PATH of the
+# distro. The symlink to rmcctrl is /usr/sbin/rsct/bin/rmcctrl .
+RMCCTRL = 'rmcctrl'
+
+
+def handle(name, _cfg, _cloud, _log, _args):
+    if not subp.which(RMCCTRL):
+        LOG.debug("No '%s' in path, disabled", RMCCTRL)
+        return
+
+    LOG.debug(
+        'Making the IPv6 up explicitly. '
+        'Ensuring IPv6 interface is not being handled by NetworkManager '
+        'and it is  restarted to re-establish the communication with '
+        'the hypervisor')
+
+    ifaces = find_ipv6_ifaces()
+
+    # Setting NM_CONTROLLED=no for IPv6 interface
+    # making it down and up
+
+    if len(ifaces) == 0:
+        LOG.debug("Did not find any interfaces with ipv6 addresses.")
+    else:
+        for iface in ifaces:
+            refresh_ipv6(iface)
+            disable_ipv6(sysconfig_path(iface))
+        restart_network_manager()
+
+
+def find_ipv6_ifaces():
+    info = netinfo.netdev_info()
+    ifaces = []
+    for iface, data in info.items():
+        if iface == "lo":
+            LOG.debug('Skipping localhost interface')
+        if len(data.get("ipv4", [])) != 0:
+            # skip this interface, as it has ipv4 addrs
+            continue
+        ifaces.append(iface)
+    return ifaces
+
+
+def refresh_ipv6(interface):
+    # IPv6 interface is explicitly brought up, subsequent to which the
+    # RMC services are restarted to re-establish the communication with
+    # the hypervisor.
+    subp.subp(['ip', 'link', 'set', interface, 'down'])
+    subp.subp(['ip', 'link', 'set', interface, 'up'])
+
+
+def sysconfig_path(iface):
+    return '/etc/sysconfig/network-scripts/ifcfg-' + iface
+
+
+def restart_network_manager():
+    subp.subp(['systemctl', 'restart', 'NetworkManager'])
+
+
+def disable_ipv6(iface_file):
+    # Ensuring that the communication b/w the hypervisor and VM is not
+    # interrupted due to NetworkManager. For this purpose, as part of
+    # this function, the NM_CONTROLLED is explicitly set to No for IPV6
+    # interface and NetworkManager is restarted.
+    try:
+        contents = util.load_file(iface_file)
+    except IOError as e:
+        if e.errno == errno.ENOENT:
+            LOG.debug("IPv6 interface file %s does not exist\n",
+                      iface_file)
+        else:
+            raise e
+
+    if 'IPV6INIT' not in contents:
+        LOG.debug("Interface file %s did not have IPV6INIT", iface_file)
+        return
+
+    LOG.debug("Editing interface file %s ", iface_file)
+
+    # Dropping any NM_CONTROLLED or IPV6 lines from IPv6 interface file.
+    lines = contents.splitlines()
+    lines = [line for line in lines if not search(line)]
+    lines.append("NM_CONTROLLED=no")
+
+    with open(iface_file, "w") as fp:
+        fp.write("\n".join(lines) + "\n")
+
+
+def search(contents):
+    # Search for any NM_CONTROLLED or IPV6 lines in IPv6 interface file.
+    return(
+        contents.startswith("IPV6ADDR") or
+        contents.startswith("IPADDR6") or
+        contents.startswith("IPV6INIT") or
+        contents.startswith("NM_CONTROLLED"))
+
+
+def refresh_rmc():
+    # To make a healthy connection between RMC daemon and hypervisor we
+    # refresh RMC. With refreshing RMC we are ensuring that making IPv6
+    # down and up shouldn't impact communication between RMC daemon and
+    # hypervisor.
+    # -z : stop Resource Monitoring & Control subsystem and all resource
+    # managers, but the command does not return control to the user
+    # until the subsystem and all resource managers are stopped.
+    # -s : start Resource Monitoring & Control subsystem.
+    try:
+        subp.subp([RMCCTRL, '-z'])
+        subp.subp([RMCCTRL, '-s'])
+    except Exception:
+        util.logexc(LOG, 'Failed to refresh the RMC subsystem.')
+        raise