Installation von des Netzwerküberwachungssystems Nagios 1.1 auf einem Debian-Rechner

Transcription

1 Installation von des Netzwerküberwachungssystems Nagios 1.1 auf einem Debian-Rechner Voraussetzungen: gcc usw. Installiertes SNMP Installiertes Perl apt-get install libgd2 apt-get install libgd2-dev apt-get install libpng2 apt-get install libpng2-dev apt-get install libjpeg62 apt-get install libjpeg62-dev apt-get install zlib1g apt-get install zlib1g-dev Laufender Webserver (Apache) Folgende Pakte von holen: nagios-1.1.tar.gz nagios-plugins tar.gz nrpe-2.0.tar.gz nsclient_201.zip (Grundsystem) (Module zum Überwachen von einzelnen Diensten) (Client und Server zum Abfragen von Servern im Netz) (Client und Server zum Abfragen von Windows-Servern) Zielverzeichnis erstellen: mkdir /usr/local/nagios Gruppe nagios und User nagios erstellen: addgroup nagios addr --home /usr/local/nagios --ingroup nagios nagios Passwort für nagios-user aus /etc/shadow entfernen und /bin/false als Shell eintragen; ggf. / etc/shells entsprechend erweitern chown nagios:nagios /usr/local/nagios Nagios kompilieren und installieren: cd /usr/src tar xvfz nagios-1.1.tar.gz cd nagios-1.1./configure --with-gd-lib=/usr/lib --with-gd-inc=/usr/include make all make make install (make install-init) make install-commandmode make install-config

2 Installieren der Plugins: cd /usr/src tar xvfz nagios-plugins tar.gz cd nagios-plugins /configure make make install Web-Interface konfigurieren: httpd.conf um folgende Einträge ergänzen: ScriptAlias /nagios/cgi-bin/ /usr/local/nagios/sbin/ <Directory "/usr/local/nagios/sbin/"> AllowOverride AuthConfig Options ExecCGI Order allow,deny Allow from all </Directory> Alias /nagios/ /usr/local/nagios/share/ <Directory "/usr/local/nagios/share"> Options None AllowOverride AuthConfig Order allow,deny Allow from all </Directory> Apache neu starten: /etc/init.d/apache restart Datei.htaccess in den Verzeichnissen /usr/local/nagios/share und /usr/local/nagios/sbin mit folgendem Inhalt anlegen: AuthName "Nagios Access" AuthType Basic AuthUserFile /usr/local/nagios/etc/htpasswd.rs require valid-r User anlegen: htpasswd -c /usr/local/nagios/etc/htpasswd.rs nagiosadmin htpasswd /usr/local/nagios/etc/htpasswd.rs <r> Beispiel etc-verzeichnis sichern: Konfiguration von Nagios: cp -a /usr/local/nagios/etc /usr/local/nagios/etc-sic In /usr/local/nagios/etc die Dateien umbenennen (jeweils -sample entfernen): cgi.cfg-sample checkcommands.cfg-sample

3 contactgroups.cfg-sample contacts.cfg-sample dependencies.cfg-sample escalations.cfg-sample hostgroups.cfg-sample hosts.cfg-sample misccommands.cfg-sample nagios.cfg-sample resource.cfg-sample services.cfg-sample timeperiods.cfg-sample cgi.cfg: CGI.CFG - Sample CGI Configuration File for Nagios Last Modified: main_config_file=/usr/local/nagios/etc/nagios.cfg physical_html_path=/usr/local/nagios/share url_html_path=/nagios show_context_help=1 nagios_=/usr/local/nagios/libexec/check_nagios / usr/local/nagios/va r/status.log 5 'nagios' _authentication=1 default_r_name=guest authorized_for_system_information=nagiosadmin,chris authorized_for_configuration_information=nagiosadmin,chris authorized_for_system_commands=nagiosadmin,chris authorized_for_all_services=nagiosadmin,chris authorized_for_all_hosts=nagiosadmin,chris authorized_for_all_service_commands=nagiosadmin,chris authorized_for_all_host_commands=nagiosadmin,chris hostextinfo[es-eds]=/serverinfo/eseds.html;novell40.gif;novell40.jpg;novell40. gd2;intranetware 4.11;100,50;3.5,0.0,-1.5; hostextinfo[rosie]=/serverinfo/rosie.html;win40.gif;win40.jpg;win40.gd2;nt Serv er 4.0;;; serviceextinfo[es-eds;ping] = ;;PING rate serviceextinfo[rosie;security Alerts]=;security.gif;Security alerts statusmap_background_image=smbackground.gd2 default_statusmap_layout=5 default_statuswrl_layout=4 statuswrl_include=myworld.wrl ping_syntax=/bin/ping -n -U -c 5 $HOSTADDRESS$ refresh_rate=90 host_unreachable_sound=hostdown.wav host_down_sound=hostdown.wav service_critical_sound=critical.wav service_warning_sound=warning.wav service_unknown_sound=warning.wav normal_sound=noproblem.wav xeddb_host=somehost xeddb_port=someport xeddb_database=somedatabase xeddb_rname=somer xeddb_password=somepassword

4 xsddb_host=somehost xsddb_port=someport xsddb_database=somedatabase xsddb_rname=somer xsddb_password=somepassword checkcommands.cfg: Sample object config file for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation, so make sure to read the HTML documentation! Last Modified: COMMAND DEFINITIONS SYNTAX: template <templatename> name <objectname> command_name <commandname> command_line <commandline> WHERE: <templatename> = object name of another command definition that should be d as a template for this definition (optional) <objectname> = object name of command definition, referenced by other command definitions that it as a template (optional) <commandname> = name of the command, as recognized/d by Nagios <commandline> = command line SAMPLE SERVICE CHECK COMMANDS These are some example service check commands. They may or may not work on your system, as they must be modified for your plugins. See the HTML documentation on the plugins for examples of how to configure command definiti ons. 'check_tcp' command definition

5 command_name command_line check_tcp $USER1$/check_tcp -H $HOSTADDRESS$ -p $ARG1$ 'check_udp' command definition command_name check_udp command_line $USER1$/check_udp -H $HOSTADDRESS$ -p $ARG1$ 'check_ftp' command definition command_name check_ftp command_line $USER1$/check_ftp -H $HOSTADDRESS$ 'check_pop' command definition command_name check_pop command_line $USER1$/check_pop -H $HOSTADDRESS$ 'check_smtp' command definition command_name check_smtp command_line $USER1$/check_smtp -H $HOSTADDRESS$ 'check_nntp' command definition command_name check_nntp command_line $USER1$/check_nntp -H $HOSTADDRESS$ 'check_http' command definition command_name check_http command_line $USER1$/check_http -H $HOSTADDRESS$ 'check_telnet' command definition command_name check_telnet command_line $USER1$/check_tcp -H $HOSTADDRESS$ -p 23 'check_ping' command definition command_name check_ping command_line $USER1$/check_ping -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$ -p 5 'check_dns' command definition command_name check_dns command_line $USER1$/check_dns -H -s $HOSTADDRESS$

6 'check_hpjd' command definition command_name check_hpjd command_line $USER1$/check_hpjd -H $HOSTADDRESS$ -C public 'check_local_disk' command definition command_name check_local_disk command_line $USER1$/check_disk -w $ARG1$ -c $ARG2$ -p $ARG3$ 'check_local_rs' command definition command_name check_local_rs command_line $USER1$/check_rs -w $ARG1$ -c $ARG2$ 'check_local_procs' command definition command_name check_local_procs command_line $USER1$/check_procs -w $ARG1$ -c $ARG2$ -s $ARG3$ 'check_local_load' command definition command_name check_local_load command_line $USER1$/check_load -w $ARG1$ -c $ARG2$ contactgroups.cfg: Sample object config file for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation, so make sure to read the HTML documentation! Last Modified: CONTACT GROUP DEFINITIONS SYNTAX: 'novell-' contact group definition define contactgroup{ contactgroup_name Die Administratoren members chris

7 contacts.cfg: Sample object config file for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation, so make sure to read the HTML documentation! Last Modified: CONTACT DEFINITIONS SYNTAX: 'nagios' contact definition define contact{ contact_name nagios Nagios Admin service_ host_ service_ w,u,c,r host_ d,u,r service_notification_commands notify-by- ,notify-by-epager host_notification_commands host-notify-by- ,host-notify-byepag er pager 'chris' contact definition define contact{ contact_name service_ host_ service_ host_ service_notification_commands host_notification_commands chris Christian w,u,c,r d,u,r notify-by- host-notify-by- dependencies.cfg: nicht erforderlich escalations.cfg: nicht erforderlich

8 hostgroups.cfg: Sample object config file for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation, so make sure to read the HTML documentation! Last Modified: HOST GROUP DEFINITIONS SYNTAX: 'linux-servers' host group definition define hostgroup{ hostgroup_name linux-servers Linux Servers members linux01 'windows-servers' host group definition define hostgroup{ hostgroup_name windows-servers Windows Servers members hosts.cfg: HOST DEFINITIONS SYNTAX: Generic host definition template define host{ name generic-host notifications_enabled 1 event_handler_enabled 1 flap_detection_enabled 1 process_perf_data 1 retain_status_information 1 retain_nonstatus_information 1 register 0

9 'linux01' host definition define host{ generic-host linux01 Nagios Server itself address check-host-alive max_check_attempts 10 d,u,r '' host definition define host{ generic-host Ein Windows Server address check-host-alive max_check_attempts 10 d,u,r misccommands.cfg: Sample object config file for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation, so make sure to read the HTML documentation! Last Modified: COMMAND DEFINITIONS SYNTAX: template <templatename> name <objectname> command_name <commandname> command_line <commandline> WHERE: <templatename> = object name of another command definition that should be d as a template for this definition (optional) <objectname> = object name of command definition, referenced by other command definitions that it as a template (optional) <commandname> = name of the command, as recognized/d by Nagios <commandline> = command line

10 SAMPLE NOTIFICATION COMMANDS These are some example notification commands. They may or may not work on your system without modification. 'notify-by- ' command definition command_name notify-by- command_line /usr/bin/printf "%b" "***** Nagios *****\n\nnotificatio n Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress : $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $DATETIME$\n\nAdditional In fo:\n\n$output$" /usr/bin/mail -s "** $NOTIFICATIONTYPE$ alert - $HOSTALIAS$/$ SERVICEDESC$ is $SERVICESTATE$ **" $CONTACT $ 'notify-by-epager' command definition command_name notify-by-epager command_line /usr/bin/printf "%b" "Service: $SERVICEDESC$\nHost: $HOS TNAME$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\nInfo: $OUTPUT$\nDate: $DA TETIME$" /usr/bin/mail -s "$NOTIFICATIONTYPE$: $HOSTALIAS$/$SERVICEDESC$ is $S ERVICESTATE$" $CONTACTPAGER$ 'host-notify-by- ' command definition command_name host-notify-by- command_line /usr/bin/printf "%b" "***** Nagios *****\n\nnotificatio n Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOST ADDRESS$\nInfo: $OUTPUT$\n\nDate/Time: $DATETIME$\n" /usr/bin/mail -s "Host $H OSTSTATE$ alert for $HOSTNAME$!" $CONTACT $ 'host-notify-by-epager' command definition command_name host-notify-by-epager command_line /usr/bin/printf "%b" "Host '$HOSTALIAS$' is $HOSTSTATE$\ ninfo: $OUTPUT$\nTime: $DATETIME$" /usr/bin/mail -s "$NOTIFICATIONTYPE$ alert - Host $HOSTNAME$ is $HOSTSTATE$" $CONTACTPAGER$

11 nagios.cfg: NAGIOS.CFG - Sample Main Config File for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation. Last Modified: LOG FILE This is the main log file where service and host events are logged for historical purposes. This should be the first option specified in the config file!!! log_file=/usr/local/nagios/var/nagios.log cfg_file=/usr/local/nagios/etc/contactgroups.cfg cfg_file=/usr/local/nagios/etc/contacts.cfg cfg_file=/usr/local/nagios/etc/dependencies.cfg cfg_file=/usr/local/nagios/etc/escalations.cfg cfg_file=/usr/local/nagios/etc/hostgroups.cfg cfg_file=/usr/local/nagios/etc/hosts.cfg cfg_file=/usr/local/nagios/etc/services.cfg cfg_file=/usr/local/nagios/etc/timeperiods.cfg cfg_file=/usr/local/nagios/etc/checkcommands.cfg cfg_file=/usr/local/nagios/etc/misccommands.cfg cfg_dir=/usr/local/nagios/etc/services resource_file=/usr/local/nagios/etc/resource.cfg status_file=/usr/local/nagios/var/status.log nagios_r=nagios nagios_group=nagios check_external_commands=0 command_file=/usr/local/nagios/var/rw/nagios.cmd comment_file=/usr/local/nagios/var/comment.log downtime_file=/usr/local/nagios/var/downtime.log lock_file=/usr/local/nagios/var/nagios.lock temp_file=/usr/local/nagios/var/nagios.tmp log_rotation_method=d log_archive_path=/usr/local/nagios/var/archives _syslog=1 log_notifications=1 log_service_retries=1 log_host_retries=1 log_event_handlers=1

12 log_initial_states=0 log_external_commands=1 log_passive_service_checks=1 global_host_event_handler=somecommand global_service_event_handler=somecommand inter_check_delay_method=s service_interleave_factor=s max_concurrent_checks=0 service_reaper_frequency=10 sleep_time=1 service_check_timeout=60 host_check_timeout=30 event_handler_timeout=30 notification_timeout=30 ocsp_timeout=5 perfdata_timeout=5 retain_state_information=1 state_retention_file=/usr/local/nagios/var/status.sav retention_update_interval=60 _retained_program_state=0 interval_length=60 _agressive_host_checking=0 execute_service_checks=1 accept_passive_service_checks=1 enable_notifications=1 enable_event_handlers=1 process_performance_data=0 host_perfdata_command=process-host-perfdata service_perfdata_command=process-service-perfdata obsess_over_services=0 ocsp_command=somecommand check_for_orphaned_services=0 check_service_freshness=1 freshness_check_interval=60 aggregate_status_updates=1 status_update_interval=15 enable_flap_detection=0

13 low_service_flap_threshold=5.0 high_service_flap_threshold=20.0 low_host_flap_threshold=5.0 high_host_flap_threshold=20.0 date_format=iso8601 illegal_object_name_chars=`~!$%^&* '"<>?,()= illegal_macro_output_chars=`~$& '"<> admin_ =nagios admin_pager=pagenagios EOF (End of file) resource.cfg: nicht erforderlich services.cfg: Sample object config file for Nagios Read the documentation for more information on this configuration file. I've provided some comments here, but things may not be so clear without further explanation, so make sure to read the HTML documentation! Last Modified: SERVICE DEFINITIONS SYNTAX: Generic service definition template name active_checks_enabled 1 passive_checks_enabled 1 parallelize_check 1 obsess_over_service 1 check_freshness 0 notifications_enabled 1 event_handler_enabled 1 flap_detection_enabled 1 process_perf_data 1 retain_status_information 1 retain_nonstatus_information 1 register 0

14 /usr/local/nagios/etc/services/linux01.cfg: linux01 - Der Nagiosserver selbst linux01 PING w,u,c,r check_ping!100.0,20%!500.0,60% linux01 HTTP c,r check_http linux01 Current Users retry_check_interval 2 notification_interval 240 w,u,c,r check_local_rs!75!150 linux01 Total Processes

15 linux01 Current Users retry_check_interval 2 notification_interval 240 w,u,c,r check_local_rs!75!150 linux01 Total Processes retry_check_interval 2 linux- notification_interval 240 w,u,c,r check_local_procs!150!200!rszdt linux01 /dev/hda1 Free Space linux- w,u,c,r check_local_disk!20%!10%!/dev/hda1 timeperiods.cfg: TIMEPERIOD DEFINITIONS SYNTAX: '' timeperiod definition define timeperiod{ timeperiod_name

16 24 Hours A Day, 7 Days A Week sunday 00:00-24:00 monday 00:00-24:00 tuesday 00:00-24:00 wednesday 00:00-24:00 thursday 00:00-24:00 friday 00:00-24:00 saturday 00:00-24:00 'workhours' timeperiod definition define timeperiod{ timeperiod_name workhours "Normal" Working Hours monday 09:00-17:00 tuesday 09:00-17:00 wednesday 09:00-17:00 thursday 09:00-17:00 friday 09:00-17:00 'nonworkhours' timeperiod definition define timeperiod{ timeperiod_name nonworkhours Non-Work Hours sunday 00:00-24:00 monday 00:00-09:00,17:00-24:00 tuesday 00:00-09:00,17:00-24:00 wednesday 00:00-09:00,17:00-24:00 thursday 00:00-09:00,17:00-24:00 friday 00:00-09:00,17:00-24:00 saturday 00:00-24:00 'none' timeperiod definition define timeperiod{ timeperiod_name none No Time Is A Good Time Konfiguration überprüfen mit /usr/local/nagios/bin/nagios -v -c /usr/local/nagios/etc/nagios.cfg anschließend nagios mit /etc/init.d/nagios start starten. Linux-Rechner über das Netz überwachen: Es wird das Plugin nrpe verwendet. Dieses ist aber nur erforderlich um z.b. die lokale Plattenausnutzung, lokale Prozesse etc. zu überwachen. Für Netz-Dienste (z.b. http, ftp etc.) ist KEIN Plugin erforderlich. auf dem Nagios-Server (nur einmal erforderlich): cd /usr/src tar xvfz nrpe-2.0.tar.gz cd nrpe-2.0./configure disable-ssl

17 make all cd src cp check_nrpe /usr/local/nagios/libexec Die Datei /usr/local/nagios/etc/checkcommands.cfg um folgenden Eintrag ergänzen: REMOTE HOST CHECK COMMANDS command_name command_line -c $ARG1$ check_nrpe /usr/local/nagios/libexec/check_nrpe -H $HOSTADDRESS$ auf (jedem) zu überwachenden Linux-Client: Auf dem Client müssen sowohl die nagios-plugins unter /usr/local/nagios/libexec als auch der nrpe-daemon installiert sein: cd /usr/src tar xvfz nagios-plugins tar.gu cd nagios-plugins /configure make make install cd /usr/src tar xvfz nrpe-2.0.tar.gz cd nrpe-2.0./configure disable-ssl make all cp src/nrpe /usr/local/nagios/ cp nrpe.cfg /usr/local/nagios User und Gruppe nagios hinzufügen: addgroup nagios ; addr --ingroup nagios --disabled-password nagios /usr/local/nagios/nrpe.cfg editieren: server_port=5666 allowed_hosts=<ip des abfragenden Servers> nrpe_r=nagios nrpe_group=nagios dont_blame_nrpe=0 debug=0 command_timeout=60 Beispiele: command[check_rs]=/usr/local/nagios/libexec/check_rs -w 5 -c 10 command[check_load]=/usr/local/nagios/libexec/check_load -w 15,10,5 -c 30,25,20 command[check_disk1]=/usr/local/nagios/libexec/check_disk -w 20 -c 10 -p /dev/sda2 command[check_zombie_procs]=/usr/local/nagios/libexec/check_procs -w 5 -c 10 -s Z command[check_total_procs]=/usr/local/nagios/libexec/check_procs -w 150 -c 200

18 nrpe Daemon starten: /usr/local/nagios /usr/local/nagios/nrpe -c /usr/local/nagios/nrpe.cfg -d Für den zu überwachenden Linux-Rechner müssen jetzt noch auf dem Nagios-Server folgende Dateien ergänzt bzw. erstellt werden: /usr/local/nagios/etc/hosts.cfg um folgenden Eintrag ergänzen: 'linux02' host definition define host{ generic-host linux02 Ein Linux-Rechner im Netz address check-host-alive max_check_attempts 10 d,u,r /usr/local/nagios/etc/hostgroups.cfg um folgenden Eintrag ergänzen: 'linux-servers' host group definition define hostgroup{ hostgroup_name linux-servers Linux Servers members linux01,linux02 /usr/local/nagios/etc/services/linux02.cfg erstellen: linux02 - Ein Linux-Rechner im Netz linux02 CHECK_USERS w,u,c,r check_nrpe!check_rs linux02 CHECK_LOAD

19 c,r check_nrpe!check_load linux02 CHECK_DISK_1 retry_check_interval 2 notification_interval 240 w,u,c,r check_nrpe!check_disk1 linux02 CHECK_ZOMBIE_PROCS retry_check_interval 2 notification_interval 240 w,u,c,r check_nrpe!check_zombie_procs linux02 CHECK_TOTAL_PROCS w,u,c,r check_nrpe!check_total_procs

20 Windows-Rechner über das Netz überwachen Es wird das Plugin NSClient-2.01 verwendet. Dieses ist aber nur erforderlich um z.b. die lokale Plattenausnutzung, lokale Prozesse etc. zu überwachen. Für Netz-Dienste (z.b. http, ftp etc.) ist KEIN Plugin erforderlich. Überwacht werden können z.b.: - Verbrauchter Plattenplatz - CPU-Load - Uptime - Clientversion - "Procstate": Gestartete Programme - "Servicestate": Gestartete Dienste - Verbrauchter Arbeitsspeicher auf dem Nagios-Server (nur einmal erforderlich): cd /usr/src mkdir nsclient_201 mv NSClient_2.01.zip nsclient_201 cd nsclient_201 unzip NSClient_2.01.zip cp LinuxBin/check_nt /usr/local/nagios/libexec Die Datei /usr/local/nagios/etc/checkcommands.cfg um folgende Einträge ergänzen: command_name check_nt_disk command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v USEDDISKSPACE -l $ARG1$ -w $ARG2$ -c $ARG3$ command_name check_nt_cpuload command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v CPULOAD -l $ARG1$ command_name check_nt_uptime command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v UPTIME command_name check_nt_clientversion command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v CLIENTVERSION command_name check_nt_process command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v PROCSTATE -d SHOWALL -l $ARG1$ command_name check_nt_service command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v SERVICESTATE -d SHOWALL -l $ARG1$

21 command_name check_nt_mem command_line /usr/local/nagios/libexec/check_nt -H $HOSTADDRESS$ -v MEMUSE -w $ARG1$ -c $ARG2$ /usr/local/nagios/etc/hosts.cfg um folgenden Eintrag ergänzen: '' host definition define host{ generic-host Ein Windows-Rechner im Netz address check-host-alive max_check_attempts 10 d,u,r /usr/local/nagios/etc/hostgroups.cfg um folgenden Eintrag ergänzen: 'windows-servers' host group definition define hostgroup{ hostgroup_name windows-servers Windows Servers members /usr/local/nagios/etc/services/linux02.cfg erstellen: - Ein Windows-Rechner im Netz PING w,u,c,r check_ping!100.0,20%!500.0,60% DISK C

22 c,r check_nt_disk!c!70!80 DISK D c,r check_nt_disk!d!70!80 CPULOAD c,r check_nt_cpuload!60,70,80 UPTIME c,r check_nt_uptime CLIENTVERSION

23 c,r check_nt_clientversion CHECK_PROCESSES c,r check_nt_process!explorer.exe CHECK_SERVICES c,r check_nt_service!mssqlserver,eventlog CHECK_MEMUSE c,r check_nt_mem!60,70 Mit /usr/local/nagios/bin/nagios -v -c /usr/local/nagios/etc/nagios.cfg überprüfen, ob Fehler auftreten; diese ggf. korrigieren und Nagios anschließend mit /etc/init.d/nagios restart neu starten.