build-nagios

   1 #!/usr/bin/ruby
   2
   3 # Copyright (c) 2004, 2005, 2006, 2007, 2008 Peter Palfrader <peter@palfrader.org>
   4
   5 require "yaml"
   6
   7 ORG="dsa"
   8 SHORTORG="dsa"
   9 GENERATED_PREFIX="./generated/"
  10
  11 nagios_filename = {};
  12 %w(hosts hostgroups services dependencies hostextinfo serviceextinfo).each{
  13         |x| nagios_filename[x] = GENERATED_PREFIX+"auto-#{x}.cfg"
  14 }
  15 nagios_filename['nrpe'] = GENERATED_PREFIX+"nrpe_#{ ORG }.cfg"
  16
  17
  18 MAX_CHECK_ATTEMPTS_DEFAULT=6
  19
  20 NRPE_CHECKNAME="#{ ORG }_check_nrpe"           # check that takes one argument:  service name to be checked
  21 NRPE_CHECKNAME_HOST="#{ ORG }_check_nrpe_host" # check that takes two arguments: relay host on which to run check, service name to be checked
  22
  23 HOST_TEMPLATE_NAME='generic-host'          # host templates that all our host definitions use
  24 SERVICE_TEMPLATE_NAME='generic-service'    # host templates that all our host definitions use
  25 HOST_ALIVE_CHECK='check-host-alive'        # host alive check if server is pingable
  26 NRPE_PROCESS_SERVICE='process - nrpe'      # nrpe checks will depend on this one
  27
  28
  29 def warn (msg)
  30         STDERR.puts msg
  31 end
  32 def set_if_unset(hash, key, value)
  33         hash[key] = value unless hash.has_key?(key)
  34 end
  35 def set_complain_if_set(hash, key, value, type, name)
  36         throw "#{type} definition '#{name}' has '#{key}' already defined" if hash.has_key?(key)
  37         hash[key] = value
  38 end
  39
  40 # Make an array out of something.  If there is nothing, create an empty array
  41 # if it is just a string, make a list with just that element, if it already is
  42 # an array keep it.
  43 def ensure_array(something)
  44         if (something == nil)
  45                 result = []
  46         elsif something.kind_of?(String)
  47                 result = [ something ]
  48         elsif something.kind_of?(Array)
  49                 result = something
  50         else
  51                 throw "Do now know how to make an array out of #{something}: " + something.to_yaml
  52         end
  53         return result
  54 end
  55
  56
  57 # This class keeps track of the checks done via NRPE and makes sure
  58 # each gets a unique name.
  59 #
  60 # Unforutunately NRPE limits check names to some 30 characters, so
  61 # we need to mangle service names near the end.
  62 class Nrpe
  63         def initialize
  64                 @checks = {}
  65         end
  66
  67         def make_name( name, check )
  68                 name = name.tr_s("^a-zA-Z", "_").gsub("process", "ps")
  69
  70                 result = "#{ SHORTORG }_" + name[0,19]
  71
  72                 hash = ''
  73                 skew = ''
  74                 while (@checks.has_key?(result + hash))
  75                         # hash it, so that we don't lose uniqeness by cutting it off
  76                         hash = (check+skew).crypt("$1$")
  77                         hash = hash[-5,5]  # 5 chars are enough
  78                         hash.tr!("/", "_")
  79                         skew += ' ' # change it a bit so the hash changes
  80                 end
  81                 result += hash
  82                 return result      # max of 32 or so chars
  83         end
  84
  85         def add( name, check )
  86                 if @checks.has_value? check
  87                         @checks.each_pair{ |key, value|
  88                                 return key if value == check
  89                         }
  90                 end
  91                 key = make_name(name, check)
  92                 @checks[ key ] = check
  93                 return key
  94         end
  95
  96         def checks
  97                 return @checks
  98         end
  99 end
 100 $nrpe = Nrpe.new()
 101
 102
 103 # Prints the keys and values of hash to a file
 104 # This is the function that prints the bodies of most our
 105 # host/service/etc definitions
 106 #
 107 # It skips over such keys as are listed in exclude_keys
 108 # and also skips private keys (those starting with an underscre)
 109 def print_block(fd, kind, hash, exclude_keys)
 110         fd.puts "define #{kind} {"
 111         hash.each_pair{ |key, value|
 112                 next if key[0,1] == '_'
 113                 next if exclude_keys.include? key
 114                 fd.puts "       #{key}          #{value}"
 115         }
 116         fd.puts "}"
 117         fd.puts
 118 end
 119
 120
 121 # Add the service definition service to hosts
 122 # f is the file for service definitions, deps the file for dependencies
 123 def addService(hosts, service, files)
 124
 125         set_if_unset        service, 'use'               , SERVICE_TEMPLATE_NAME
 126         set_complain_if_set service, 'host_name'         , hosts.join(',')      , 'Service', service['service_description']
 127         set_if_unset        service, 'max_check_attempts', MAX_CHECK_ATTEMPTS_DEFAULT
 128
 129         service['max_check_attempts'] = MAX_CHECK_ATTEMPTS_DEFAULT + service['max_check_attempts'] if service['max_check_attempts'] < 0
 130
 131         if service['nrpe']
 132                 throw "We already have a check_command (#{service['check_command']}) but we are in the NRPE block (nrpe: #{service['nrpe']})."+
 133                         "  This should have been caught much earlier" if service.has_key?('check_command');
 134
 135                 check = $nrpe.add(service['service_description'], service['nrpe'])
 136                 service['check_command'] = "#{ NRPE_CHECKNAME }!#{ check }"
 137
 138                 service['depends'] = ensure_array( service['depends'] )
 139                 service['depends'] << NRPE_PROCESS_SERVICE unless service['service_description'] == NRPE_PROCESS_SERVICE  # Depend on NRPE unless we are it
 140         end
 141
 142         print_block files['services'], 'service', service, %w(nrpe runfrom remotecheck
 143                                                               depends
 144                                                               hosts hostgroups excludehosts excludehostgroups)
 145
 146         if service['depends']
 147                 service['depends'].each{ |prerequisite|
 148                         hosts.each{ |host|
 149                                 prerequisite_host = host
 150                                 pre = prerequisite
 151                                 # split off a hostname if there's one
 152                                 bananasplit = prerequisite.split(':')
 153                                 if bananasplit.size == 2
 154                                         prerequisite_host = bananasplit[0]
 155                                         pre = bananasplit[1]
 156                                 elsif bananasplit.size > 2
 157                                         throw "Cannot prase prerequisite #{prerequisite} for service #{service['service_description']} into host:service"
 158                                 end
 159                                 dependency = {
 160                                         'host_name'                     => prerequisite_host,
 161                                         'service_description'           => pre,
 162                                         'dependent_host_name'           => host,
 163                                         'dependent_service_description' => service['service_description'],
 164                                         'execution_failure_criteria'    => 'n',
 165                                         'notification_failure_criteria' => 'w,u,c'
 166                                 };
 167                                 print_block files['dependencies'], 'servicedependency', dependency, %w()
 168                         }
 169                 }
 170         end
 171
 172
 173         set_complain_if_set service['_extinfo'], 'service_description' , service['service_description'], 'serviceextinfo', service['service_description']
 174         set_complain_if_set service['_extinfo'], 'host_name'           , hosts.join(',')               , 'serviceextinfo', service['service_description']
 175
 176         print_block files['serviceextinfo'], 'serviceextinfo', service['_extinfo'], %w()
 177 end
 178
 179 # hostlists in services can be given as both, single hosts and hostgroups
 180 # This functinn merges hostgroups and a simple list of hosts
 181 #
 182 # it also takes a prefix so that it can be used for excludelists as well
 183 def merge_hosts_and_hostgroups(service, servers, hostgroups, prefix)
 184         hosts = []
 185         hosts = service[prefix+'hosts'].split(/,/).map{ |x| x.strip } if service[prefix+'hosts']
 186         hosts.each{ |host|
 187                 throw "host #{host} does not exist - used in service #{service['service_description']}" unless servers[host]
 188         };
 189         if service[prefix+'hostgroups']
 190                 service[prefix+'hostgroups'].split(/,/).map{ |x| x.strip }.each{ |hg|
 191                         throw "hostgroup #{hg} does not exist - used in service #{service['service_description']}" unless hostgroups[hg]
 192                         hosts = hosts.concat hostgroups[hg]['_memberlist']
 193                 }
 194         end
 195
 196         return hosts
 197 end
 198
 199 # Figure out the hosts a given service applies to
 200 #
 201 # For a given service find the list of hosts minus excluded hosts that this service runs on
 202 def find_hosts(service, servers, hostgroups)
 203         hosts        = merge_hosts_and_hostgroups service, servers, hostgroups, ''
 204         excludehosts = merge_hosts_and_hostgroups service, servers, hostgroups, 'exclude'
 205
 206         excludehosts.each{ |host|
 207                 if hosts.delete(host) == nil
 208                         throw "Cannot remove host #{host} from service #{service['service_description']}: it's not included anyway or excluded twice."
 209                 end
 210         }
 211
 212         return hosts
 213 end
 214
 215 # Move all elements that have a key that starts with "extinfo-"
 216 # into the _extinfo subhash
 217 def split_away_extinfo(hash)
 218         hash['_extinfo'] = {}
 219         hash.keys.each{ |key|
 220                 if key[0, 8] == 'extinfo-'
 221                         hash['_extinfo'][ key[8, key.length-8] ] = hash[key]
 222                         hash.delete(key);
 223                 end
 224         }
 225 end
 226
 227
 228 #############################################################################################
 229 #############################################################################################
 230 #############################################################################################
 231
 232 # Load the config
 233 config = YAML::load( File.open( 'nagios-master.cfg' ) )
 234
 235 files = {}
 236 # Remove old created files
 237 nagios_filename.each_pair{ |name, filename|
 238         files[name] = File.new(filename, "w")
 239 }
 240
 241 #################################
 242 # create a few hostgroups
 243 #################################
 244 # create the "all" and "pingable" hostgroups
 245 config['hostgroups']['all'] = {}
 246 config['hostgroups']['all']['alias'] = "all servers"
 247 config['hostgroups']['all']['private'] = true
 248 config['hostgroups']['pingable'] = {}
 249 config['hostgroups']['pingable']['alias'] = "pingable servers"
 250 config['hostgroups']['pingable']['private'] = true
 251
 252 config['hostgroups'].each_pair{ |name, hg|
 253         throw "Empty hostgroup or hostgroup #{name} not a hash" unless hg.kind_of?(Hash)
 254         split_away_extinfo hg
 255
 256         hg['_memberlist'] = []
 257 }
 258
 259 config['servers'].each_pair{ |name, server|
 260         throw "Empty server or server #{name} not a hash" unless server.kind_of?(Hash)
 261
 262         split_away_extinfo server
 263
 264         throw "No hostgroups defined for #{name}" unless server['hostgroups']
 265         server['_hostgroups'] = server['hostgroups'].split(/,/).map{ |x| x.strip };
 266         server['_hostgroups'] << 'all'
 267         server['_hostgroups'] << 'pingable' unless server['pingable'] == false
 268
 269         server['_hostgroups'].each{ |hg|
 270                 throw "Hostgroup #{hg} is not defined" unless config['hostgroups'].has_key?(hg)
 271                 config['hostgroups'][hg]['_memberlist'] << name
 272         };
 273 }
 274
 275 ##############
 276 # HOSTS
 277 ##############
 278 config['servers'].each_pair{ |name, server|
 279         # Formerly we used 'ip' instead of 'address' in our source file
 280         # Handle this change but warn                                   XXX
 281         if server.has_key?('ip')
 282                 STDERR.puts("Host definition for #{name} has an 'ip' field.  Please use 'address' instead");
 283                 server['address'] = server['ip'];
 284                 server.delete('ip');
 285         end
 286
 287         set_complain_if_set server, 'host_name'    , name, 'Host', name
 288         set_if_unset        server, 'alias'        , name
 289         set_if_unset        server, 'use'          , HOST_TEMPLATE_NAME
 290         set_if_unset        server, 'check_command', HOST_ALIVE_CHECK    unless server['pingable'] == false
 291
 292         print_block files['hosts']      , 'host'       , server            , %w(hostgroups pingable)
 293
 294
 295
 296         # Handle hostextinfo
 297         #config['hostgroups'][  server['_hostgroups'].first  ]['_extinfo'].each_pair{ |k, v|
 298         # find the first hostgroup that has extinfo
 299         extinfo = server['_hostgroups'].collect{ |hgname | config['hostgroups'][hgname]['_extinfo'] }.delete_if{ |ei| ei.size == 0 }.first
 300         if extinfo then
 301                 extinfo.each_pair do |k, v|
 302                         # substitute hostname into the notes_url
 303                         v = sprintf(v,name) if k == 'notes_url'
 304
 305                         set_if_unset server['_extinfo'], k ,v
 306                 end
 307         end
 308
 309         set_complain_if_set server['_extinfo'], 'host_name'       , name, 'hostextinfo', name
 310         set_if_unset        server['_extinfo'], 'vrml_image'      , server['_extinfo']['icon_image'] if server['_extinfo'].has_key?('icon_image')
 311         set_if_unset        server['_extinfo'], 'statusmap_image' , server['_extinfo']['icon_image'] if server['_extinfo'].has_key?('icon_image')
 312
 313         print_block files['hostextinfo'], 'hostextinfo', server['_extinfo'], %w()
 314 }
 315
 316
 317
 318 ##############
 319 # HOSTGROUPS
 320 ##############
 321 config['hostgroups'].each_pair{ |name, hg|
 322         next if hg['private']
 323
 324         set_complain_if_set hg, 'hostgroup_name', name                       , 'Hostgroup', name
 325         set_complain_if_set hg, 'members'       , hg['_memberlist'].join(","), 'Hostgroup', name
 326
 327         print_block files['hostgroups'], 'hostgroup', hg, %w()
 328 }
 329
 330
 331 ##############
 332 # SERVICES and DEPENDENCIES
 333 ##############
 334 config['services'].each{ |service|
 335         throw "Empty service or service not a hash" unless service.kind_of?(Hash)
 336
 337         split_away_extinfo service
 338
 339
 340         # Both 'name' and 'service_description' are valid for a service's name
 341         # Internally we only use service_description as that's nagios' official term
 342         if service.has_key?('name')
 343                 throw "Service definition has both a name (#{service['name']})" +
 344                       "and a service_description (#{service['service_description']})" if service.has_key?('service_description')
 345                 #STDERR.puts("Service definition #{service['name']} has a 'name' field.  Please use 'service_description' instead");
 346                 service['service_description'] = service['name'];
 347                 service.delete('name');
 348         end
 349         # Both 'check' and 'check_command' are valid for a service's check command
 350         # Internally we only use check_command as that's nagios' official term
 351         if service.has_key?('check')
 352                 throw "Service definition has both a check (#{service['check']})" +
 353                       "and a check_command (#{service['check_command']})" if service.has_key?('check_command')
 354                 #STDERR.puts("Service definition #{service['service_description']} has a 'check' field.  Please use 'check_command' instead");
 355                 service['check_command'] = service['check'];
 356                 service.delete('check');
 357         end
 358
 359
 360         hosts = find_hosts service, config['servers'], config['hostgroups']
 361         throw "no hosts for service #{service['service_description']}" if hosts.empty?
 362
 363         throw "nrpe, check, and remotecheck are mutually exclusive in service #{service['service_description']}" if
 364                 (service['nrpe'] ? 1 : 0) +
 365                 (service['check_command'] ? 1 : 0) +
 366                 (service['remotecheck'] ? 1 : 0)  >= 2
 367
 368         if service['runfrom'] && service['remotecheck']
 369                 # If the service check is to be run from a remote monitor server ("relay")
 370                 # add that as an NRPE check to be run on the relay and make this
 371                 # service also depend on NRPE on the relay
 372                 relay = service['runfrom']
 373
 374                 hosts.each{ |host|
 375                         # how to recursively copy this thing?
 376                         hostservice = YAML::load( service.to_yaml )
 377                         host_ip = config['servers'][host]['address']
 378                         throw "For some reason I do not have an address for #{host}.  This shouldn't be." unless host_ip
 379
 380                         check = $nrpe.add("#{host}_#{hostservice['service_description']}", hostservice['remotecheck'].gsub(/\$HOSTADDRESS\$/, host_ip))
 381                         hostservice['check_command'] = "#{NRPE_CHECKNAME_HOST}!#{ config['servers'][ relay ]['address'] }!#{ check }"
 382
 383                         # Make sure dependencies are an array.  If there are none, create an empty array
 384                         # if depends is just a string, make a list with just that element
 385                         hostservice['depends'] = ensure_array( hostservice['depends'] )
 386                         # And append this new dependency
 387                         hostservice['depends'] << "#{ relay }:#{ NRPE_PROCESS_SERVICE }";
 388
 389                         addService( [ host ], hostservice, files)
 390                 }
 391         elsif service['runfrom'] || service['remotecheck']
 392                 throw "runfrom and remotecheck must either appear both or not at all in service #{service['service_description']}"
 393                 throw "must not remotecheck without runfrom" if service['remotecheck']
 394         else
 395                 addService(hosts, service, files)
 396         end
 397 }
 398
 399
 400 ##############
 401 # NRPE config file
 402 ##############
 403 $nrpe.checks.each_pair{ |name, check|
 404         files['nrpe'].puts "command[#{ name }]=#{ check }"
 405 }
 406
 407