Merge lp:~clint-fewbar/charms/precise/nagios/add-monitors-2 into lp:charms/nagios

[Clint Byrum]

A significant refactor of the charm's relations.

* Deprecate the 'monitoring' interface - never used in any other charm in the official store.
* Adds the 'monitors' interface to communicate complex monitoring information.
* Reworks to use 'pynag' library (embedded in a deb) for nagios configuration editting.
* Adds 'extraconfig' option for users to add extra config options.
* Enables 'external commands' so that checks can be rescheduled by an administrator.

A significant refactor of the charm's relations.

* Deprecate the 'monitoring' interface - never used in any other charm in the official store.
* Adds the 'monitors' interface to communicate complex monitoring information.
* Reworks to use 'pynag' library (embedded in a deb) for Nagios configuration editing.
* Adds 'extraconfig' option for users to add extra config options.
* Enables 'external commands' so that checks can be rescheduled by an administrator.

[Clint Byrum (clint-fewbar)]

For an example of the changes needed to add remote and local monitors, see

https://code.launchpad.net/~clint-fewbar/charms/precise/mysql/add-monitors/+merge/118000

[Mark Mims (mark-mims)]

Please add default user/pass instructions...
maybe mention how to use `juju ssh nagios/0 sudo cat /var/lib/juju/nagios.passwd`

review: Approve

=== added file '.bzrignore'
--- .bzrignore	1970-01-01 00:00:00 +0000
+++ .bzrignore	2012-08-02 21:28:44 +0000
@@ -0,0 +1,1 @@
+data

=== modified file 'README'
--- README	2012-05-14 07:24:34 +0000
+++ README	2012-08-02 21:28:44 +0000
@@ -10,8 +10,21 @@
 
 This should result in your Nagios monitoring all of the service units.
 
-TODO:
-- Add a nagios-nrpe subordinate charm to make it easier to use local
-  plugins via NRPE
-- Create a proper 'monitoring' interface that charms can use to define
-  what they want monitored remotely.
+monitors interface
+==================
+
+The monitors interface expects three fields:
+
+* monitors - YAML matching the monitors yaml spec. See
+  example.monitors.yaml for more information.
+* target-id - Assign any monitors to this target host definition.
+* target-address - Optional, specifies the host of the target to
+  monitor. This must be specified by at least one unit so that the
+  intended target-id will be monitorable.
+
+nrpe
+====
+
+There is an NRPE subordinate charm which must be used for any local
+monitors.  See the 'nrpe' charm's README for information on how to
+make use of it.

=== added file 'config.yaml'
--- config.yaml	1970-01-01 00:00:00 +0000
+++ config.yaml	2012-08-02 21:28:44 +0000
@@ -0,0 +1,8 @@
+options:
+    extraconfig:
+        type: string
+        default: ""
+        description: |
+            Any additional nagios configuration you would like to
+            add can be set into this element. It will be placed in
+            /etc/nagios3/conf.d/extra.cfg

=== added directory 'debs'
=== added file 'debs/pynag_0.4.2-1_all.deb'
Binary files debs/pynag_0.4.2-1_all.deb	1970-01-01 00:00:00 +0000 and debs/pynag_0.4.2-1_all.deb	2012-08-02 21:28:44 +0000 differ
=== added file 'example.monitors.yaml'
--- example.monitors.yaml	1970-01-01 00:00:00 +0000
+++ example.monitors.yaml	2012-08-02 21:28:44 +0000
@@ -0,0 +1,30 @@
+# Version of the spec, mostly ignored but 0.3 is the current one
+version: '0.3'
+# Dict with just 'local' and 'remote' as parts
+monitors:
+    # local monitors need an agent to be handled. See nrpe charm for
+    # some example implementations
+    local:
+        # procrunning checks for a running process named X (no path)
+        procrunning:
+            # Multiple procrunning can be defined, this is the "name" of it
+            nagios3:
+                min: 1
+                max: 1
+                executable: nagios3
+    # Remote monitors can be polled directly by a remote system
+    remote:
+        # do a request on the HTTP protocol
+        http:
+            nagios:
+                port: 80
+                path: /nagios3/
+                # expected status response (otherwise just look for 200)
+                status: 'HTTP/1.1 401'
+                # Use as the Host: header (the server address will still be used to connect() to)
+                host: www.fewbar.com
+        mysql:
+            # Named basic check
+            basic:
+                username: monitors
+                password: abcdefg123456

=== modified file 'hooks/common.py'
--- hooks/common.py	2012-05-14 23:48:24 +0000
+++ hooks/common.py	2012-08-02 21:28:44 +0000
@@ -2,7 +2,26 @@
 import socket
 import os
 import os.path
-
+import re
+import sqlite3
+import shutil
+import tempfile
+
+from pynag import Model
+
+INPROGRESS_DIR = '/etc/nagios3-inprogress'
+INPROGRESS_CFG = '/etc/nagios3-inprogress/nagios.cfg'
+INPROGRESS_CONF_D = '/etc/nagios3-inprogress/conf.d'
+CHARM_CFG = '/etc/nagios3-inprogress/conf.d/charm.cfg'
+MAIN_NAGIOS_BAK = '/etc/nagios3.bak'
+MAIN_NAGIOS_DIR = '/etc/nagios3'
+MAIN_NAGIOS_CFG = '/etc/nagios3/nagios.cfg'
+PLUGIN_PATH = '/usr/lib/nagios/plugins'
+
+Model.cfg_file = INPROGRESS_CFG
+Model.pynag_directory = INPROGRESS_CONF_D
+
+reduce_RE = re.compile('[\W_]')
 
 def check_ip(n):
     try:
@@ -28,59 +47,208 @@
     if check_ip(hostname):
         # Some providers don't provide hostnames, so use the remote unit name.
         ip_address = hostname
-        hostname = remote_unit.replace('/','-')
     else:
         ip_address = socket.getaddrinfo(hostname, None)[0][4][0]
-    return (ip_address, hostname)
-
-# relationId-hostname-config.cfg
-host_config_path_template = '/etc/nagios3/conf.d/%s-%s-config.cfg'
-
-hostgroup_template = """
-define hostgroup {
-    hostgroup_name  %(name)s
-    alias   %(alias)s
-    members %(members)s
-}
-"""
-hostgroup_path_template = '/etc/nagios3/conf.d/%s-hostgroup.cfg'
-
-
-def remove_hostgroup(relation_id):
-    hostgroup_path = hostgroup_path_template % (relation_id)
-    if os.path.exists(hostgroup_path):
-        os.unlink(hostgroup_path)
-
-
-def handle_hostgroup(relation_id):
-    p = subprocess.Popen(["relation-list","-r",relation_id],
-                         stdout=subprocess.PIPE)
-    services = {}
-    for unit in p.stdout:
-        unit = unit.strip()
-        service_name = unit.strip().split('/')[0]
-        (_, hostname) = get_ip_and_hostname(unit, relation_id)
-        if service_name in services:
-            services[service_name].add(hostname)
+    return (ip_address, remote_unit.replace('/', '-'))
+
+
+def refresh_hostgroups():
+    """ Not the most efficient thing but since we're only
+        parsing what is already on disk here its not too bad """ 
+    hosts = [ x['host_name'] for x in Model.Host.objects.all if x['host_name'] ]
+
+    hgroups = {}
+    for host in hosts:
+        try:
+            (service, unit_id) = host.rsplit('-', 1)
+        except ValueError:
+            continue
+        if service in hgroups:
+            hgroups[service].append(host)
         else:
-            services[service_name] = set([hostname])
-    p.communicate()
-    if p.returncode != 0:
-        raise RuntimeError('relation-list failed with code %d' % p.returncode)
-
-    hostgroup_path = hostgroup_path_template % (relation_id)
-    for service, members in services.iteritems():
-        with open(hostgroup_path, 'w') as outfile:
-            outfile.write(hostgroup_template % {'name': service,
-                'alias': service, 'members': ','.join(members)})
-
-def refresh_hostgroups(relation_name):
-    p = subprocess.Popen(["relation-ids",relation_name],
-        stdout=subprocess.PIPE)
-    relids = [ relation_id.strip() for relation_id in p.stdout ]
-    for relation_id in relids:
-        remove_hostgroup(relation_id)
-        handle_hostgroup(relation_id)
-    p.communicate()
-    if p.returncode != 0:
-        raise RuntimeError('relation-ids failed with code %d' % p.returncode)
+            hgroups[service] = [host]
+
+    # Find existing autogenerated
+    auto_hgroups = Model.Hostgroup.objects.filter(notes__contains='#autogenerated#')
+    auto_hgroups = [ x.get_attribute('hostgroup_name') for x in auto_hgroups ]
+
+    # Delete the ones not in hgroups
+    to_delete = set(auto_hgroups).difference(set(hgroups.keys()))
+    for hgroup_name in to_delete:
+        try:
+            hgroup = Model.Hostgroup.objects.get_by_shortname(hgroup_name)
+            hgroup.delete()
+        except ValueError:
+            pass
+
+    for hgroup_name, members in hgroups.iteritems():
+        try:
+            hgroup = Model.Hostgroup.objects.get_by_shortname(hgroup_name)
+        except ValueError:
+            hgroup = Model.Hostgroup()
+            hgroup.set_filename(CHARM_CFG)
+            hgroup.set_attribute('hostgroup_name', hgroup_name)
+            hgroup.set_attribute('notes', '#autogenerated#')
+
+        hgroup.set_attribute('members', ','.join(members))
+        hgroup.save()
+
+
+def _make_check_command(args):
+    args = [str(arg) for arg in args]
+    # There is some worry of collision, but the uniqueness of the initial
+    # command should be enough.
+    signature = reduce_RE.sub('_', ''.join(
+                [os.path.basename(arg) for arg in args]))
+    Model.Command.objects.reload_cache()
+    try:
+        cmd = Model.Command.objects.get_by_shortname(signature)
+    except ValueError:
+        cmd = Model.Command()
+        cmd.set_attribute('command_name', signature)
+        cmd.set_attribute('command_line', ' '.join(args))
+        cmd.save()
+    return signature
+
+def _extend_args(args, cmd_args, switch, value):
+    args.append(value)
+    cmd_args.extend((switch, '"$ARG%d$"' % len(args)))
+
+def customize_http(service, name, extra):
+    args = []
+    cmd_args = []
+    plugin = os.path.join(PLUGIN_PATH, 'check_http')
+    port = extra.get('port', 80)
+    path = extra.get('path', '/')
+    args = [port, path]
+    cmd_args = [plugin, '-p', '"$ARG1$"', '-u', '"$ARG2$"']
+    if 'status' in extra:
+        _extend_args(args, cmd_args, '-e', extra['status'])
+    if 'host' in extra:
+        _extend_args(args, cmd_args, '-H', extra['host'])
+        cmd_args.extend(('-I', '$HOSTADDRESS$'))
+    else:
+        cmd_args.extend(('-H', '$HOSTADDRESS$'))
+    check_command = _make_check_command(cmd_args)
+    cmd = '%s!%s' % (check_command, '!'.join([str(x) for x in args]))
+    service.set_attribute('check_command', cmd)
+    return True
+
+
+def customize_mysql(service, name, extra):
+    plugin = os.path.join(PLUGIN_PATH, 'check_mysql')
+    args = []
+    cmd_args = [plugin,'-H', '$HOSTADDRESS$']
+    if 'user' in extra:
+        _extend_args(args, cmd_args, '-u', extra['user'])
+    if 'password' in extra:
+        _extend_args(args, cmd_args, '-p', extra['password'])
+    check_command = _make_check_command(cmd_args)
+    cmd = '%s!%s' % (check_command, '!'.join([str(x) for x in args]))
+    service.set_attribute('check_command', cmd)
+    return True
+
+
+def customize_nrpe(service, name, extra):
+    plugin = os.path.join(PLUGIN_PATH, 'check_nrpe')
+    args = []
+    cmd_args = [plugin,'-H', '$HOSTADDRESS$']
+    if name in ('mem','swap'):
+        cmd_args.extend(('-c', 'check_%s' % name))
+    elif 'command' in extra:
+        cmd_args.extend(('-c', extra['command']))
+    else:
+        return False
+    check_command = _make_check_command(cmd_args)
+    cmd = '%s!%s' % (check_command, '!'.join([str(x) for x in args]))
+    service.set_attribute('check_command', cmd)
+    return True
+
+
+def customize_service(service, family, name, extra):
+    customs = { 'http': customize_http,
+                'mysql': customize_mysql,
+                'nrpe': customize_nrpe}
+    if family in customs:
+        return customs[family](service, name, extra)
+    return False
+
+
+def get_pynag_host(target_id, owner_unit=None, owner_relation=None):
+    try:
+        host = Model.Host.objects.get_by_shortname(target_id)
+    except ValueError:
+        host = Model.Host()
+        host.set_filename(CHARM_CFG)
+        host.set_attribute('host_name', target_id)
+        host.set_attribute('use', 'generic-host')
+        host.save()
+        host = Model.Host.objects.get_by_shortname(target_id)
+    apply_host_policy(target_id, owner_unit, owner_relation)
+    return host
+
+
+def get_pynag_service(target_id, service_name):
+    services = Model.Service.objects.filter(host_name=target_id,
+                    service_description=service_name)
+    if len(services) == 0:
+        service = Model.Service()
+        service.set_filename(CHARM_CFG)
+        service.set_attribute('service_description', service_name)
+        service.set_attribute('host_name', target_id)
+        service.set_attribute('use', 'generic-service')
+    else:
+        service = services[0]
+    return service
+
+
+def apply_host_policy(target_id, owner_unit, owner_relation):
+    ssh_service = get_pynag_service(target_id, 'SSH')
+    ssh_service.set_attribute('check_command', 'check_ssh')
+    ssh_service.save()
+
+
+def get_valid_relations():
+    for x in subprocess.Popen(['relation-ids', 'monitors'], 
+        stdout=subprocess.PIPE).stdout:
+        yield x.strip()
+    for x in subprocess.Popen(['relation-ids', 'nagios'], 
+        stdout=subprocess.PIPE).stdout:
+        yield x.strip()
+
+
+def get_valid_units(relation_id):
+    for x in subprocess.Popen(['relation-list', '-r', relation_id], 
+                              stdout=subprocess.PIPE).stdout:
+        yield x.strip()
+
+
+def _replace_in_config(find_me, replacement):
+    with open(INPROGRESS_CFG) as cf:
+        with tempfile.NamedTemporaryFile(dir=INPROGRESS_DIR, delete=False) as new_cf:
+            for line in cf:
+                new_cf.write(line.replace(find_me, replacement))
+            new_cf.flush()
+            os.chmod(new_cf.name, 0644)
+            os.unlink(INPROGRESS_CFG)
+            os.rename(new_cf.name, INPROGRESS_CFG)
+
+
+def initialize_inprogress_config():
+    if os.path.exists(INPROGRESS_DIR):
+        shutil.rmtree(INPROGRESS_DIR)
+    shutil.copytree(MAIN_NAGIOS_DIR, INPROGRESS_DIR)
+    _replace_in_config(MAIN_NAGIOS_DIR, INPROGRESS_DIR)
+    if os.path.exists(CHARM_CFG):
+        os.unlink(CHARM_CFG)
+
+
+def flush_inprogress_config():
+    if not os.path.exists(INPROGRESS_DIR):
+        return
+    _replace_in_config(INPROGRESS_DIR, MAIN_NAGIOS_DIR)
+    if os.path.exists(MAIN_NAGIOS_BAK):
+        shutil.rmtree(MAIN_NAGIOS_BAK)
+    if os.path.exists(MAIN_NAGIOS_DIR):
+        shutil.move(MAIN_NAGIOS_DIR, MAIN_NAGIOS_BAK)
+    shutil.move(INPROGRESS_DIR, MAIN_NAGIOS_DIR)

=== added symlink 'hooks/config-changed'
=== target is u'upgrade-charm'
=== modified file 'hooks/install'
--- hooks/install	2012-05-13 23:04:19 +0000
+++ hooks/install	2012-08-02 21:28:44 +0000
@@ -17,7 +17,22 @@
 echo nagios3-cgi nagios3/adminpassword-repeat password $PASSWORD | debconf-set-selections
 
 DEBIAN_FRONTEND=noninteractive apt-get -qy \
-	install nagios3 nagios-plugins python-cheetah dnsutils debconf-utils
+	install nagios3 nagios-plugins python-cheetah dnsutils debconf-utils nagios-nrpe-plugin
+
+# Ideally these would be moved into the distro ASAP
+if [ -d debs ] ; then
+    dpkg -i debs/*.deb
+fi
+
+# enable external commands per README.Debian file
+if ! grep '^check_external_commands=1$' /etc/nagios3/nagios.cfg ; then
+    echo check_external_commands=1 >> /etc/nagios3/nagios.cfg
+fi
+# || :'s are for idempotency
+service nagios3 stop || :
+dpkg-statoverride --update --add nagios www-data 2710 /var/lib/nagios3/rw || :
+dpkg-statoverride --update --add nagios nagios 751 /var/lib/nagios3 || :
+service nagios3 start
 
 # For the admin interface
 open-port 80

=== removed symlink 'hooks/legacy-relation-changed'
=== target was u'nagios-relation-changed'
=== removed symlink 'hooks/legacy-relation-departed'
=== target was u'nagios-relation-departed'
=== added symlink 'hooks/monitors-relation-broken'
=== target is u'monitors-relation-changed'
=== added file 'hooks/monitors-relation-changed'
--- hooks/monitors-relation-changed	1970-01-01 00:00:00 +0000
+++ hooks/monitors-relation-changed	2012-08-02 21:28:44 +0000
@@ -0,0 +1,125 @@
+#!/usr/bin/python
+# monitors-relation-changed - Process monitors.yaml into remote nagios monitors
+# Copyright Canonical 2012 Canonical Ltd. All Rights Reserved
+# Author: Clint Byrum <[e-mail]>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import sys
+import os
+import subprocess
+import yaml
+import json
+import re
+import string
+
+
+from common import (customize_service, get_pynag_host,
+        get_pynag_service, refresh_hostgroups,
+        get_valid_relations, get_valid_units,
+        initialize_inprogress_config, flush_inprogress_config)
+
+
+def main(argv):
+    # Note that one can pass in args positionally, 'monitors.yaml targetid
+    # and target-address' so the hook can be tested without being in a hook
+    # context.
+    #
+    if len(argv) > 1:
+        relation_settings = {'monitors': open(argv[1]).read(),
+                             'target-id': argv[2]}
+        if len(argv) > 3:
+            relation_settings['target-address'] = argv[3]
+        all_relations = {'monitors:99': {'testing/0': relation_settings}}
+    else:
+        all_relations = {}
+        for relid in get_valid_relations():
+            (relname, relnum) = relid.split(':')
+            for unit in get_valid_units(relid):
+                relation_settings = json.loads(
+                        subprocess.check_output(['relation-get', '--format=json',
+                            '-r', relid,
+                            '-',unit]).strip())
+
+                if relation_settings is None or relation_settings == '':
+                    continue
+
+                if relname == 'monitors':
+                    if ('monitors' not in relation_settings
+                            or 'target-id' not in relation_settings):
+                        continue
+                else:
+                    # Fake it for the more generic 'nagios' relation'
+                    relation_settings['target-id'] = unit.replace('/','-')
+                    relation_settings['target-address'] = relation_settings['private-address']
+                    relation_settings['monitors'] = {'monitors': {'remote': {} } }
+
+                if relid not in all_relations:
+                    all_relations[relid] = {}
+
+                all_relations[relid][unit] = relation_settings
+
+    # Hack to work around http://pad.lv/1025478
+    targets_with_addresses = set()
+    for relid, units in all_relations.iteritems():
+        for unit, relation_settings in units.iteritems():
+            if 'target-address' in relation_settings:
+                targets_with_addresses.add(relation_settings['target-id'])
+    new_all_relations = {}
+    for relid, units in all_relations.iteritems():
+        for unit, relation_settings in units.iteritems():
+            if relation_settings['target-id'] in targets_with_addresses:
+                if relid not in new_all_relations:
+                    new_all_relations[relid] = {}
+                new_all_relations[relid][unit] = relation_settings
+    all_relations = new_all_relations
+
+    initialize_inprogress_config()
+    for relid, units in all_relations.iteritems():
+        apply_relation_config(relid, units)
+    refresh_hostgroups()
+    flush_inprogress_config()
+    os.system('service nagios3 reload')
+
+def apply_relation_config(relid, units):
+    for unit, relation_settings in units.iteritems():
+        monitors = relation_settings['monitors']
+        target_id = relation_settings['target-id']
+        # If not set, we don't mess with it, as multiple services may feed
+        # monitors in for a particular address. Generally a primary will set this
+        # to its own private-address
+        target_address = relation_settings.get('target-address', None)
+
+        if type(monitors) != dict:
+            monitors = yaml.safe_load(monitors)
+
+        # Output nagios config
+        host = get_pynag_host(target_id)
+
+        if target_address is not None:
+            host.set_attribute('address', target_address)
+            host.save()
+
+        for mon_family, mons in monitors['monitors']['remote'].iteritems():
+            for mon_name, mon in mons.iteritems():
+                service_name = '%s-%s' % (target_id, mon_name)
+                service = get_pynag_service(target_id, service_name)
+                if customize_service(service, mon_family, mon_name, mon):
+                    service.save()
+                else:
+                    print('Ignoring %s due to unknown family %s' % (mon_name,
+                                                                    mon_family))
+
+if __name__ == '__main__':
+    main(sys.argv)

=== added symlink 'hooks/monitors-relation-departed'
=== target is u'monitors-relation-changed'
=== added file 'hooks/mymonitors-relation-joined'
--- hooks/mymonitors-relation-joined	1970-01-01 00:00:00 +0000
+++ hooks/mymonitors-relation-joined	2012-08-02 21:28:44 +0000
@@ -0,0 +1,17 @@
+#!/bin/bash
+if [ -n "$JUJU_RELATION_ID" ] ; then
+    # single relation joined
+    rels=$JUJU_RELATION_ID
+else
+    # Refresh from upgrade or some other place
+    rels=`relation-ids mymonitors`
+fi
+
+target_id=${JUJU_UNIT_NAME//\//-}
+
+for rel in $rels ; do
+    relation-set -r $rel \
+        monitors="`cat monitors.yaml`" \
+        target-address=`unit-get private-address` \
+        target-id=$target_id
+done

=== added symlink 'hooks/nagios-relation-broken'
=== target is u'monitors-relation-changed'
=== removed file 'hooks/nagios-relation-broken'
--- hooks/nagios-relation-broken	2012-05-14 07:15:54 +0000
+++ hooks/nagios-relation-broken	1970-01-01 00:00:00 +0000
@@ -1,12 +0,0 @@
-#!/usr/bin/python
-import glob
-import os
-
-import common
-
-common.remove_hostgroup(os.environ['JUJU_RELATION_ID'])
-glob_target = common.host_config_path_template % (os.environ['JUJU_RELATION_ID'], '*')
-print 'Removing relation config files: %s' % (glob_target)
-for oldconfig in glob.glob(glob_target):
-    print 'Removing %s' % (oldconfig)
-    os.unlink(oldconfig)

=== added symlink 'hooks/nagios-relation-changed'
=== target is u'monitors-relation-changed'
=== removed file 'hooks/nagios-relation-changed'
--- hooks/nagios-relation-changed	2012-05-14 07:15:54 +0000
+++ hooks/nagios-relation-changed	1970-01-01 00:00:00 +0000
@@ -1,79 +0,0 @@
-#!/usr/bin/env python
-
-import string
-import sys
-import os
-import os.path
-import yaml
-import subprocess
-from common import *
-
-from Cheetah.Template import Template
-
-def write_service_template(service, host, description, command):
-        service = service.replace("__hostname__", host)
-        service = service.replace("__description__", description)
-        service = service.replace("__command__", command)
-        return service
-
-def write_host_template(host, hostname, ip_address):
-        host = host.replace("__hostname__", hostname)
-        host = host.replace("__alias__", hostname)
-        host = host.replace("__address__", ip_address)
-        return host
-
-
-def main():
-        for var in ['JUJU_REMOTE_UNIT', 'JUJU_RELATION_ID']:
-            if var not in os.environ:
-                print "%s must be set" % (var)
-                return 1
-        relation_id = os.environ["JUJU_RELATION_ID"]
-        relation_name = os.path.basename(sys.argv[0]).split('-')[0]
-        remote_unit = os.environ["JUJU_REMOTE_UNIT"]
-
-        service_name, _ = remote_unit.split("/")
-        (ip_address, hostname) = get_ip_and_hostname(remote_unit)
-
-        nagios_service = ""
-        host_template = """
-        define host {
-                use            generic-host    ; Name of host template to use
-                host_name      __hostname__
-                alias          __alias__
-                address        __address__
-        }
-"""
-        service_template = """
-        define service {
-                use                     generic-service    ; Name of service template to use
-                host_name                               __hostname__
-                service_description             __description__
-                check_command                   __command__
-        }
-"""
-
-        # write a single host
-        host_template = write_host_template(host_template, hostname, ip_address)
-        nagios_service += host_template
-
-        # all hosts should be running SSH
-        nagios_service += write_service_template(service_template, hostname, 'SSH', 'check_ssh')
-
-        namespace = {'hostname': hostname, 'nagios_config':nagios_service}
-        t = Template(open('hooks/templates/nagios.tmpl').read(), searchList=[namespace])
-        config_file = host_config_path_template % (relation_id, hostname)
-        f = open(config_file, 'w')
-        f.write(str(t))
-        f.close()
-
-        refresh_hostgroups(relation_name)
-
-        print "Restarting nagios"
-        subprocess.call(["service", "nagios3", "restart"])
-        return 0
-
-if __name__ == '__main__':
-        sys.exit(main())
-
-

=== added symlink 'hooks/nagios-relation-departed'
=== target is u'monitors-relation-changed'
=== removed file 'hooks/nagios-relation-departed'
--- hooks/nagios-relation-departed	2012-05-14 07:15:54 +0000
+++ hooks/nagios-relation-departed	1970-01-01 00:00:00 +0000
@@ -1,10 +0,0 @@
-#!/usr/bin/python
-
-import common
-import os
-
-relation_id = os.environ['JUJU_RELATION_ID']
-(_,hostname) = common.get_ip_and_hostname(os.environ['JUJU_REMOTE_UNIT'])
-os.unlink(common.host_config_path_template % (relation_id, hostname))
-common.refresh_hostgroups(os.path.basename(sys.argv[0]).split('-')[0])
-subprocess.call(['service','nagios3','restart'])

=== added file 'hooks/test-common.py'
--- hooks/test-common.py	1970-01-01 00:00:00 +0000
+++ hooks/test-common.py	2012-08-02 21:28:44 +0000
@@ -0,0 +1,50 @@
+from common import ObjectTagCollection
+import os
+
+from tempfile import NamedTemporaryFile
+
+""" This is meant to test the ObjectTagCollection bits. It should
+    probably be made into a proper unit test. """
+
+x = ObjectTagCollection('test-units')
+y = ObjectTagCollection('test-relids')
+
+o = NamedTemporaryFile(delete=False)
+o2 = NamedTemporaryFile(delete=False)
+o3 = NamedTemporaryFile(delete=True)
+o.write('some content')
+o.flush()
+
+x.tag_object(o.name, 'box-9')
+x.tag_object(o.name, 'nrpe-1')
+y.tag_object(o.name, 'monitors:2')
+x.tag_object(o2.name, 'box-10')
+x.tag_object(o2.name, 'nrpe-2')
+y.tag_object(o2.name, 'monitors:2')
+x.tag_object(o3.name, 'other-0')
+y.tag_object(o3.name, 'monitors:3')
+x.untag_object(o.name, 'box-9')
+x.cleanup_untagged()
+
+if not os.path.exists(o.name):
+    raise RuntimeError(o.name)
+
+x.kill_tag('nrpe-1')
+x.cleanup_untagged()
+
+if os.path.exists(o.name):
+    raise RuntimeError(o.name)
+
+if not os.path.exists(o2.name):
+    raise RuntimeError(o2.name)
+
+y.kill_tag('monitors:2')
+y.cleanup_untagged(['monitors:1','monitors:3'])
+
+if os.path.exists(o.name):
+    raise RuntimeError(o2.name)
+
+if os.path.exists(o2.name):
+    raise RuntimeError(o2.name)
+
+x.destroy()

=== modified file 'hooks/upgrade-charm'
--- hooks/upgrade-charm	2012-05-14 07:15:54 +0000
+++ hooks/upgrade-charm	2012-08-02 21:28:44 +0000
@@ -1,2 +1,15 @@
 #!/bin/sh
-juju-log -l WARNING 'Relations have been radically changed. Its best to remove any existing relationships and re-establish them.'
+set -e
+legacy_relations="`relation-ids legacy`"
+if [ -n "$legacy_relations" ] ; then
+    juju-log -l WARNING 'Relations have been radically changed. The monitoring interface is not supported anymore.'
+    juju-log -l WARNING 'Please use the generic juju-info or the monitors interface'
+fi
+if [ -n "`config-get extraconfig`" ] ; then
+    config-get extraconfig > /etc/nagios3/conf.d/extra.cfg
+else
+    rm -f /etc/nagios3/conf.d/extra.cfg
+fi
+# Refresh these hooks entirely
+hooks/mymonitors-relation-joined
+hooks/monitors-relation-changed

=== modified file 'metadata.yaml'
--- metadata.yaml	2012-05-22 22:10:53 +0000
+++ metadata.yaml	2012-08-02 21:28:44 +0000
@@ -8,8 +8,12 @@
 provides:
   website:
     interface: http
+  mymonitors:
+    interface: monitors
 requires:
   legacy:
     interface: monitoring
   nagios:
     interface: juju-info
+  monitors:
+    interface: monitors

=== added file 'monitors.yaml'
--- monitors.yaml	1970-01-01 00:00:00 +0000
+++ monitors.yaml	2012-08-02 21:28:44 +0000
@@ -0,0 +1,11 @@
+version: '0.3'
+monitors:
+    local:
+        procrunning:
+            min: 1
+            name: '/usr/sbin/nagios3'
+    remote:
+        http:
+            nagios:
+                path: /nagios3/
+                status: 'HTTP/1.1 401'

=== modified file 'revision'
--- revision	2012-05-14 23:48:24 +0000
+++ revision	2012-08-02 21:28:44 +0000
@@ -1,1 +1,1 @@
-22
+40