Add checks for openvswitch and helper function to enable the checks

charmhelpers/contrib/charmsupport/nrpe.py

@@ -29,6 +29,7 @@
 import yaml
 
 from charmhelpers.core.hookenv import (
+    DEBUG,
     config,
     hook_name,
     local_unit,
@@ -509,6 +510,37 @@ def add_haproxy_checks(nrpe, unit_name):
         check_cmd='check_haproxy_queue_depth.sh')
 
 
+def add_openvswitch_checks(nrpe, unit_name):
+    """
+    Add checks for openvswitch
+
+    :param NRPE nrpe: NRPE object to add check to
+    :param str unit_name: Unit name to use in check description
+    """
+    enable_sudo_for_openvswitch_checks()
+    nrpe.add_check(
+        shortname='openvswitch',
+        description='Check Open vSwitch {%s}' % unit_name,
+        check_cmd='check_openvswitch.py')
+
+
+def enable_sudo_for_openvswitch_checks():
+    sudoers_dir = "/etc/sudoers.d"
+    sudoers_mode = 0o100440
+    ovs_sudoers_file = "99-check_openvswitch"
+    ovs_sudoers_entry = "nagios ALL=(root) NOPASSWD: /usr/bin/ovs-vsctl show"
+    dest = os.path.join(sudoers_dir, ovs_sudoers_file)
+    try:
+        with open(dest, "w") as sudoer_file:
+            sudoer_file.write(ovs_sudoers_entry)
+        os.chmod(dest, sudoers_mode)
+        os.chown(dest, uid=0, gid=0)
+    except (OSError, IOError) as e:
+        log("Failed to setup sudoers file for check_openvswitch: {}".format(e))
+    else:
+        log("Sudoers file for check_openvswitch installed: {}".format(dest), DEBUG)
+
+
 def remove_deprecated_check(nrpe, deprecated_services):
     """
     Remove checks fro deprecated services in list

charmhelpers/contrib/openstack/files/check_openvswitch.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+# -*- coding: us-ascii -*-
+"""Check for issues with NVME hardware devices."""
+
+import argparse
+import re
+import subprocess
+import sys
+
+from nagios_plugin3 import CriticalError, UnknownError, try_check
+
+
+def parse_ovs_status():
+    """Check for errors in 'ovs-vsctl show' output."""
+    try:
+        cmd = ["/usr/bin/sudo", "/usr/bin/ovs-vsctl", "show"]
+        ovs_output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+    except subprocess.CalledProcessError as e:
+        raise UnknownError(
+            "UNKNOWN: Failed to query ovs: {}".format(
+                e.output.decode(errors="ignore").rstrip()
+            )
+        )
+
+    ovs_vsctl_show_errors = []
+    ovs_error_re = re.compile(r"^.*error: (?P<message>.+)$", re.I)
+    for line in ovs_output.decode(errors="ignore").splitlines():
+        m = ovs_error_re.match(line)
+        if m:
+            ovs_vsctl_show_errors.append(m.group("message"))
+
+    if ovs_vsctl_show_errors:
+        numerrs = len(ovs_vsctl_show_errors)
+        raise CriticalError(
+            "CRITICAL: Found {} error(s) in ovs-vsctl show: "
+            "{}".format(numerrs, ", ".join(ovs_vsctl_show_errors))
+        )
+
+    print("OK: no errors found in openvswitch")
+
+
+def parse_args(argv=None):
+    """Process CLI arguments."""
+    parser = argparse.ArgumentParser(
+        prog="check_openvswitch",
+        description=(
+            "this program checks openvswitch status and outputs an "
+            "appropriate Nagios status line"
+        ),
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+    return parser.parse_args(argv)
+
+
+def main(argv):
+    """Define main subroutine."""
+    parse_args(argv)
+    try_check(parse_ovs_status)
+
+
+if __name__ == "__main__":
+    main(sys.argv[1:])