1 files changed, 113 insertions, 0 deletions
diff --git a/agents/crosslink/fence_crosslink.py b/agents/crosslink/fence_crosslink.py
new file mode 100755
index 0000000..7cfc90c
--- /dev/null
+++ b/agents/crosslink/fence_crosslink.py
@@ -0,0 +1,113 @@
+#!@PYTHON@ -tt
+
+# Copyright (c) 2020 Red Hat
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+import atexit
+import logging
+import sys
+sys.path.append("@FENCEAGENTSLIBDIR@")
+from fencing import (all_opt, atexit_handler, check_input,  # noqa: E402
+                     fence_action, process_input, run_command, run_delay,
+                     show_docs)
+
+logger = logging.getLogger(__name__)
+logger.setLevel("WARNING")
+
+
+def get_power_status(conn, options):
+    logger.debug("get_power_status(): %s" % options)
+    ip = options['--crosscableip']
+    timeout = options['--timeout']
+    # This returns 'off' if not a single ICMP packet gets answered during the
+    # whole timeout window. (the ping executable will return 1 in such case and
+    # 0 if even a single packet gets replied to)
+    (status, stdout, stderr) = run_command(options, "ping -w%s -n %s" %
+                                           (timeout, ip))
+    logger.debug("get_power_status(): %s - Stdout: %s - Stderr: %s" %
+                 (status, stdout, stderr))
+    if status == 0:
+        return "on"
+    else:
+        return "off"
+
+
+def set_power_status(conn, options):
+    logger.debug("set_power_status(): %s" % options)
+    # If we got here it means the previous call to get_power_status() returned
+    # on At this point we've been invoked but the node is still reachable over
+    # the cross connect, so we can just error out.
+    ip = options['--crosscableip']
+    if options['--action'] == 'off':
+        logger.error("We've been asked to turn off the node at %s but the "
+                     "cross-cable link is up so erroring out" % ip)
+        sys.exit(1)
+    elif options['--action'] == 'on':
+        logger.error("We've been asked to turn on the node at %s but the "
+                     "cross-cable link is off so erroring out" % ip)
+        sys.exit(1)
+    else:
+        logger.error("set_power_status() was called with action %s which "
+                     "is not supported" % options['--action'])
+        sys.exit(1)
+
+
+def define_new_opts():
+    all_opt["crosscableip"] = {
+        "getopt": "a:",
+        "longopt": "crosscableip",
+        "help": "-a, --crosscableip=[IP]      IP over the cross-cable link",
+        "required": "1",
+        "shortdesc": "Cross-cable IP",
+        "order": 1
+    }
+    all_opt["timeout"] = {
+        "getopt": "T:",
+        "longopt": "timeout",
+        "help": "-T, --timeout=[seconds]      timeout in seconds",
+        "required": "0",
+        "shortdesc": "No ICMP reply in 5 seconds -> Node is considered dead",
+        "default": "5",
+        "order": 1
+    }
+
+
+def main():
+    atexit.register(atexit_handler)
+
+    device_opt = ["crosscableip", "timeout", "no_password", "no_login", "port"]
+    define_new_opts()
+
+    options = check_input(device_opt, process_input(device_opt))
+
+    docs = {}
+    docs["shortdesc"] = "Fence agent for cross-link two-node clusters"
+    docs["longdesc"] = "This agent helps two-node clusters to tackle the " \
+                       "situation where one node lost power, cannot be " \
+                       "fenced by telling pacemaker that if the node is not " \
+                       "reachable over the crosslink cable, we can assume " \
+                       "it is dead"
+    docs["vendorurl"] = ""
+    show_docs(options, docs)
+
+    run_delay(options)
+
+    result = fence_action(None, options, set_power_status, get_power_status)
+    sys.exit(result)
+
+
+if __name__ == "__main__":
+    main()