# Copyright 2014-2015 Canonical Limited.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Compatibility with the nrpe-external-master charm"""
# Copyright 2012 Canonical Ltd.
#
# Authors:
# Matthew Wedgwood <matthew.wedgwood@canonical.com>
import subprocess
import pwd
import grp
import os
import glob
import shutil
import re
import shlex
import yaml
from charmhelpers.core.hookenv import (
config,
hook_name,
local_unit,
log,
relation_ids,
relation_set,
relations_of_type,
)
from charmhelpers.core.host import service
from charmhelpers.core import host
# This module adds compatibility with the nrpe-external-master and plain nrpe
# subordinate charms. To use it in your charm:
#
# 1. Update metadata.yaml
#
# provides:
# (...)
# nrpe-external-master:
# interface: nrpe-external-master
# scope: container
#
# and/or
#
# provides:
# (...)
# local-monitors:
# interface: local-monitors
# scope: container
#
# 2. Add the following to config.yaml
#
# nagios_context:
# default: "juju"
# type: string
# description: |
# Used by the nrpe subordinate charms.
# A string that will be prepended to instance name to set the host name
# in nagios. So for instance the hostname would be something like:
# juju-myservice-0
# If you're running multiple environments with the same services in them
# this allows you to differentiate between them.
# nagios_servicegroups:
# default: ""
# type: string
# description: |
# A comma-separated list of nagios servicegroups.
# If left empty, the nagios_context will be used as the servicegroup
#
# 3. Add custom checks (Nagios plugins) to files/nrpe-external-master
#
# 4. Update your hooks.py with something like this:
#
# from charmsupport.nrpe import NRPE
# (...)
# def update_nrpe_config():
# nrpe_compat = NRPE()
# nrpe_compat.add_check(
# shortname = "myservice",
# description = "Check MyService",
# check_cmd = "check_http -w 2 -c 10 http://localhost"
# )
# nrpe_compat.add_check(
# "myservice_other",
# "Check for widget failures",
# check_cmd = "/srv/myapp/scripts/widget_check"
# )
# nrpe_compat.write()
#
# def config_changed():
# (...)
# update_nrpe_config()
#
# def nrpe_external_master_relation_changed():
# update_nrpe_config()
#
# def local_monitors_relation_changed():
# update_nrpe_config()
#
# 4.a If your charm is a subordinate charm set primary=False
#
# from charmsupport.nrpe import NRPE
# (...)
# def update_nrpe_config():
# nrpe_compat = NRPE(primary=False)
#
# 5. ln -s hooks.py nrpe-external-master-relation-changed
# ln -s hooks.py local-monitors-relation-changed
class CheckException(Exception):
pass
class Check(object):
shortname_re = '[A-Za-z0-9-_.]+$'
service_template = ("""
#---------------------------------------------------
# This file is Juju managed
#---------------------------------------------------
define service {{
use active-service
host_name {nagios_hostname}
service_description {nagios_hostname}[{shortname}] """
"""{description}
check_command check_nrpe!{command}
servicegroups {nagios_servicegroup}
}}
""")
def __init__(self, shortname, description, check_cmd):
super(Check, self).__init__()
# XXX: could be better to calculate this from the service name
if not re.match(self.shortname_re, shortname):
raise CheckException("shortname must match {}".format(
Check.shortname_re))
self.shortname = shortname
self.command = "check_{}".format(shortname)
# Note: a set of invalid characters is defined by the
# Nagios server config
# The default is: illegal_object_name_chars=`~!$%^&*"|'<>?,()=
self.description = description
self.check_cmd = self._locate_cmd(check_cmd)
def _get_check_filename(self):
return os.path.join(NRPE.nrpe_confdir, '{}.cfg'.format(self.command))
def _get_service_filename(self, hostname):
return os.path.join(NRPE.nagios_exportdir,
'service__{}_{}.cfg'.format(hostname, self.command))
def _locate_cmd(self, check_cmd):
search_path = (
'/usr/lib/nagios/plugins',
'/usr/local/lib/nagios/plugins',
)
parts = shlex.split(check_cmd)
for path in search_path:
if os.path.exists(os.path.join(path, parts[0])):
command = os.path.join(path, parts[0])
if len(parts) > 1:
command += " " + " ".join(parts[1:])
return command
log('Check command not found: {}'.format(parts[0]))
return ''
def _remove_service_files(self):
if not os.path.exists(NRPE.nagios_exportdir):
return
for f in os.listdir(NRPE.nagios_exportdir):
if f.endswith('_{}.cfg'.format(self.command)):
os.remove(os.path.join(NRPE.nagios_exportdir, f))
def remove(self, hostname):
nrpe_check_file = self._get_check_filename()
if os.path.exists(nrpe_check_file):
os.remove(nrpe_check_file)
self._remove_service_files()
def write(self, nagios_context, hostname, nagios_servicegroups):
nrpe_check_file = self._get_check_filename()
with open(nrpe_check_file, 'w') as nrpe_check_config:
nrpe_check_config.write("# check {}\n".format(self.shortname))
if nagios_servicegroups:
nrpe_check_config.write(
"# The following header was added automatically by juju\n")
nrpe_check_config.write(
"# Modifying it will affect nagios monitoring and alerting\n")
nrpe_check_config.write(
"# servicegroups: {}\n".format(nagios_servicegroups))
nrpe_check_config.write("command[{}]={}\n".format(
self.command, self.check_cmd))
if not os.path.exists(NRPE.nagios_exportdir):
log('Not writing service config as {} is not accessible'.format(
NRPE.nagios_exportdir))
else:
self.write_service_config(nagios_context, hostname,
nagios_servicegroups)
def write_service_config(self, nagios_context, hostname,
nagios_servicegroups):
self._remove_service_files()
templ_vars = {
'nagios_hostname': hostname,
'nagios_servicegroup': nagios_servicegroups,
'description': self.description,
'shortname': self.shortname,
'command': self.command,
}
nrpe_service_text = Check.service_template.format(**templ_vars)
nrpe_service_file = self._get_service_filename(hostname)
with open(nrpe_service_file, 'w') as nrpe_service_config:
nrpe_service_config.write(str(nrpe_service_text))
def run(self):
subprocess.call(self.check_cmd)
class NRPE(object):
nagios_logdir = '/var/log/nagios'
nagios_exportdir = '/var/lib/nagios/export'
nrpe_confdir = '/etc/nagios/nrpe.d'
homedir = '/var/lib/nagios' # home dir provided by nagios-nrpe-server
def __init__(self, hostname=None, primary=True):
super(NRPE, self).__init__()
self.config = config()
self.primary = primary
self.nagios_context = self.config['nagios_context']
if 'nagios_servicegroups' in self.config and self.config['nagios_servicegroups']:
self.nagios_servicegroups = self.config['nagios_servicegroups']
else:
self.nagios_servicegroups = self.nagios_context
self.unit_name = local_unit().replace('/', '-')
if hostname:
self.hostname = hostname
else:
nagios_hostname = get_nagios_hostname()
if nagios_hostname:
self.hostname = nagios_hostname
else:
self.hostname = "{}-{}".format(self.nagios_context, self.unit_name)
self.checks = []
# Iff in an nrpe-external-master relation hook, set primary status
relation = relation_ids('nrpe-external-master')
if relation:
log("Setting charm primary status {}".format(primary))
for rid in relation_ids('nrpe-external-master'):
relation_set(relation_id=rid, relation_settings={'primary': self.primary})
def add_check(self, *args, **kwargs):
self.checks.append(Check(*args, **kwargs))
def remove_check(self, *args, **kwargs):
if kwargs.get('shortname') is None:
raise ValueError('shortname of check must be specified')
# Use sensible defaults if they're not specified - these are not
# actually used during removal, but they're required for constructing
# the Check object; check_disk is chosen because it's part of the
# nagios-plugins-basic package.
if kwargs.get('check_cmd') is None:
kwargs['check_cmd'] = 'check_disk'
if kwargs.get('description') is None:
kwargs['description'] = ''
check = Check(*args, **kwargs)
check.remove(self.hostname)
def write(self):
try:
nagios_uid = pwd.getpwnam('nagios').pw_uid
nagios_gid = grp.getgrnam('nagios').gr_gid
except Exception:
log("Nagios user not set up, nrpe checks not updated")
return
if not os.path.exists(NRPE.nagios_logdir):
os.mkdir(NRPE.nagios_logdir)
os.chown(NRPE.nagios_logdir, nagios_uid, nagios_gid)
nrpe_monitors = {}
monitors = {"monitors": {"remote": {"nrpe": nrpe_monitors}}}
for nrpecheck in self.checks:
nrpecheck.write(self.nagios_context, self.hostname,
self.nagios_servicegroups)
nrpe_monitors[nrpecheck.shortname] = {
"command": nrpecheck.command,
}
# update-status hooks are configured to firing every 5 minutes by
# default. When nagios-nrpe-server is restarted, the nagios server
# reports checks failing causing unneccessary alerts. Let's not restart
# on update-status hooks.
if not hook_name() == 'update-status':
service('restart', 'nagios-nrpe-server')
monitor_ids = relation_ids("local-monitors") + \
relation_ids("nrpe-external-master")
for rid in monitor_ids:
relation_set(relation_id=rid, monitors=yaml.dump(monitors))
def get_nagios_hostcontext(relation_name='nrpe-external-master'):
"""
Query relation with nrpe subordinate, return the nagios_host_context
:param str relation_name: Name of relation nrpe sub joined to
"""
for rel in relations_of_type(relation_name):
if 'nagios_host_context' in rel:
return rel['nagios_host_context']
def get_nagios_hostname(relation_name='nrpe-external-master'):
"""
Query relation with nrpe subordinate, return the nagios_hostname
:param str relation_name: Name of relation nrpe sub joined to
"""
for rel in relations_of_type(relation_name):
if 'nagios_hostname' in rel:
return rel['nagios_hostname']
def get_nagios_unit_name(relation_name='nrpe-external-master'):
"""
Return the nagios unit name prepended with host_context if needed
:param str relation_name: Name of relation nrpe sub joined to
"""
host_context = get_nagios_hostcontext(relation_name)
if host_context:
unit = "%s:%s" % (host_context, local_unit())
else:
unit = local_unit()
return unit
def add_init_service_checks(nrpe, services, unit_name, immediate_check=True):
"""
Add checks for each service in list
:param NRPE nrpe: NRPE object to add check to
:param list services: List of services to check
:param str unit_name: Unit name to use in check description
:param bool immediate_check: For sysv init, run the service check immediately
"""
for svc in services:
# Don't add a check for these services from neutron-gateway
if svc in ['ext-port', 'os-charm-phy-nic-mtu']:
next
upstart_init = '/etc/init/%s.conf' % svc
sysv_init = '/etc/init.d/%s' % svc
if host.init_is_systemd():
nrpe.add_check(
shortname=svc,
description='process check {%s}' % unit_name,
check_cmd='check_systemd.py %s' % svc
)
elif os.path.exists(upstart_init):
nrpe.add_check(
shortname=svc,
description='process check {%s}' % unit_name,
check_cmd='check_upstart_job %s' % svc
)
elif os.path.exists(sysv_init):
cronpath = '/etc/cron.d/nagios-service-check-%s' % svc
checkpath = '%s/service-check-%s.txt' % (nrpe.homedir, svc)
croncmd = (
'/usr/local/lib/nagios/plugins/check_exit_status.pl '
'-e -s /etc/init.d/%s status' % svc
)
cron_file = '*/5 * * * * root %s > %s\n' % (croncmd, checkpath)
f = open(cronpath, 'w')
f.write(cron_file)
f.close()
nrpe.add_check(
shortname=svc,
description='service check {%s}' % unit_name,
check_cmd='check_status_file.py -f %s' % checkpath,
)
# if /var/lib/nagios doesn't exist open(checkpath, 'w') will fail
# (LP: #1670223).
if immediate_check and os.path.isdir(nrpe.homedir):
f = open(checkpath, 'w')
subprocess.call(
croncmd.split(),
stdout=f,
stderr=subprocess.STDOUT
)
f.close()
os.chmod(checkpath, 0o644)
def copy_nrpe_checks(nrpe_files_dir=None):
"""
Copy the nrpe checks into place
"""
NAGIOS_PLUGINS = '/usr/local/lib/nagios/plugins'
default_nrpe_files_dir = os.path.join(
os.getenv('CHARM_DIR'),
'hooks',
'charmhelpers',
'contrib',
'openstack',
'files')
if not nrpe_files_dir:
nrpe_files_dir = default_nrpe_files_dir
if not os.path.exists(NAGIOS_PLUGINS):
os.makedirs(NAGIOS_PLUGINS)
for fname in glob.glob(os.path.join(nrpe_files_dir, "check_*")):
if os.path.isfile(fname):
shutil.copy2(fname,
os.path.join(NAGIOS_PLUGINS, os.path.basename(fname)))
def add_haproxy_checks(nrpe, unit_name):
"""
Add checks for each service in list
:param NRPE nrpe: NRPE object to add check to
:param str unit_name: Unit name to use in check description
"""
nrpe.add_check(
shortname='haproxy_servers',
description='Check HAProxy {%s}' % unit_name,
check_cmd='check_haproxy.sh')
nrpe.add_check(
shortname='haproxy_queue',
description='Check HAProxy queue depth {%s}' % unit_name,
check_cmd='check_haproxy_queue_depth.sh')