M. Bechtel, S. Blümel, A. Quignon1 Linux Network Server Group: Nagios Marc Bechtel Sebastian Blümel Alexandre Quignon

M. Bechtel, S. Blümel, A. Quignon2 Table of Contents 1. Overview 2. Requirements (MYSQL, APACHE, CONFIGS…) 3. A short introduction to Nagios 4. Nagios-Configuration with Fruity 5. Installation and Configuration Problems 6. Nagios in Action 7. Nagios with SNMP and Cisco

M. Bechtel, S. Blümel, A. Quignon3 Requirements YUM-Installation Manager  MySQL  Apache  PHP  Postfix Self installed  Nagios 2.5  Fruity 1 RC 1./chkconfig --add httpd./chkconfig --level 235 httpd on./chkconfig –add mysql./chkconfig --level 235 mysql on./chkconfig –add nagios./chkconfig --level 235 nagios on 6 different runlevels 0 - Halt the system 1 - Single-user mode 2 - Multi-user mode (without NFS) 3 - Multi-user mode 5 - Multi-user mode, graphical login 6 - Reboot the system

M. Bechtel, S. Blümel, A. Quignon4 Table of Contents 1. Overview 2. Requirements (MYSQL, APACHE, CONFIGS…) 3. A short introduction to Nagios 4. Nagios-Configuration with Fruity 5. Installation and Configuration Problems 6. Nagios in Action 7. Nagios with SNMP and Cisco

M. Bechtel, S. Blümel, A. Quignon5 What is Nagios? Nagios is System and network monitoring application  Developed by Ethan Galstad  Formerly know as Netsaint (2002)  Nagios is open source Software (General Public License)  current verion is 2.5 „Nagios is quite powerful and flexible, but unfortunately its not very friendly to newbies. Why? Because it takes a lot of work to get it installed and configured properly. That being said, if you stick with it and manage to get it up and running, you’ll never want to be without it. :-)“

M. Bechtel, S. Blümel, A. Quignon6 Monitoring of… Nagios can supervise:  Hosts (Windows, Linux, …) and host resources (Disk Usage, Load)  Services (FTP, Mail, HTTP, …)  SNMP Traps  other hardware devices (like temperature sensors, filling level indicator,…) In case of emergency send notifications :  , pager, SMS  any user-defined method through plug-in system

M. Bechtel, S. Blümel, A. Quignon7 Plug-in concept How is this achieved?  build in check services (DNS, SNMP, SMTP, ICMP,…)  by simple plug-in design that allows users to easily develop their own service checks Upside: You can monitor just about anything you can think of! Downside: Nagios cannot produce graphs of collected data because it has no further information about what you are monitoring!

M. Bechtel, S. Blümel, A. Quignon8 Configuring Nagios As all Linux Software Nagios heavily relies on config files! We will have a (short) look at:  httpd.conf  nagios.cfg  hosts.cfg & hostgroup.cfg  contacts.cfg & contactsgroup.cfg  services.cfg and commands.cfg Do I have to configure all by hand?

M. Bechtel, S. Blümel, A. Quignon9 Configuration-Files

M. Bechtel, S. Blümel, A. Quignon10 Apache: httpd.conf ScriptAlias /nagios/cgi-bin /usr/local/nagios/sbin Options ExecCgi AllowOverride AuthConfig Order allow, deny Allow from all Alias /nagios /usr/local/nagios/share Options ExecCgi AllowOverride AuthConfig Order allow, deny Allow from all Configure Script Alias For The CGIs: default installation expects to find them accessible at Configure Alias For The HTML Files: to make the HTML files accessible via the web server

M. Bechtel, S. Blümel, A. Quignon11 Main Configuration File: nagios.cfg Location: /usr/local/nagios/etc/nagios.cfg Refers to all other config files First file read by the Nagios process Extract: log_file=/var/log/nagios/nagios.log cfg_file=/usr/local/nagios/etc/hosts.cfg cfg_file=/usr/local/nagios/etc/commands.cfg

M. Bechtel, S. Blümel, A. Quignon12 host.cfg and hostgroup.cfg define host { host_name FTP alias FTP Server address check_command Ping check_period 24x7 contact_groups LNS } define hostgroup{ hostgroup_name AllServers alias all Server members FTP } Description : A host definition is used to define a physical server, workstation, device, etc. that resides on your network. Description : A host group definition is used to group one or more hosts together for display purposes in the CGIs.

M. Bechtel, S. Blümel, A. Quignon13 contactgroups.cfg and contacts.cfg define contactgroup{ contactgroup_name LNS alias ThisIsATestGroup members Marc } define contact{ contact_name Marc alias Marc Bechtel host_notification_period 24x7 host_notification_commands send_notification_mail_host } Description : A contact group definition is used to group one or more contacts together for the purpose of sending out alert/recovery notifications. Description : A contact definition is used to identify someone who should be contacted in the event of a problem on your network.

M. Bechtel, S. Blümel, A. Quignon14 Configuration-Files

M. Bechtel, S. Blümel, A. Quignon15 services.cfg and commands.cfg define service { service_description Ping check_command Ping max_check_attempts 2 contact_groups LNS } define command{ command_name Ping command_line /usr/local/nagios/libexec/ch eck_icmp $HOSTADDRESS$ -c 500,10% } Description : A service definition is used to identify a "service" that runs on a host. Description : How to perform a service check.

M. Bechtel, S. Blümel, A. Quignon16 Verifying Your Nagios Configuration: Pre-Flight Check with the –v option /usr/local/nagios/bin/nagios -v Nagios verifies that you have defined the necessary data relationships for monitoring. 1. Verify that all contacts are a member of at least one contact group. 2. Verify that all contacts specified in each contact group are valid. 3. Verify that all hosts are a member of at least one host group. 4. Verify that all hosts specified in each host group are valid. 5. Verify that all hosts have at least one service associated with them. …

M. Bechtel, S. Blümel, A. Quignon17 Table of Contents Overview Requirements (MYSQL, APACHE, CONFIGS…) A short introduction to Nagios Nagios-Configuration with Fruity Installation and Configuration Problems Nagios in Action Nagios with SNMP and Cisco

M. Bechtel, S. Blümel, A. Quignon18 Fruity What is Fruity?  PHP based web-frontend  Open Source project Why are we using Fruity?  Simplicity  Easy to make changes  No manual *.cfg file handling Demonstation of Fruity

M. Bechtel, S. Blümel, A. Quignon19 Table of Contents Overview Requirements (MYSQL, APACHE, CONFIGS…) A short introduction to Nagios Nagios-Configuration with Fruity Installation and Configuration Problems Nagios in Action Nagios with SNMP and Cisco

M. Bechtel, S. Blümel, A. Quignon20 Fruity Configuration Problems SELinux blocking write access for Fruity File missing:  /usr/local/nagios/objectconf/oconf.cfg Two processes at shutdown

M. Bechtel, S. Blümel, A. Quignon21 Table of Contents Overview Requirements (MYSQL, APACHE, CONFIGS…) A short introduction to Nagios Nagios-Configuration with Fruity Installation and Configuration Problems Nagios in Action Nagios with SNMP and Cisco

M. Bechtel, S. Blümel, A. Quignon22 Monitoring What is offered by Nagios ?  Host Monitoring  Service Monitoring  Status Map  3D Map

M. Bechtel, S. Blümel, A. Quignon23 Reporting Nagios Standard  Trends  Availability  Alert Diagrams  Notification / Event Log PNP  Performance Diagrams

M. Bechtel, S. Blümel, A. Quignon24 Notification Mail command Miranda Mailbox Root

M. Bechtel, S. Blümel, A. Quignon25 Table of Contents Overview Requirements (MYSQL, APACHE, CONFIGS…) A short introduction to Nagios Nagios-Configuration with Fruity Installation and Configuration Problems Nagios in Action Nagios with SNMP and Cisco

M. Bechtel, S. Blümel, A. Quignon26 What’s a MIB Used to manage devices in a Network Hierarchical database All objects are addressed through a OID (Object Identifier) Is used by SNMP (Simple Network Management Protocol) There are Standard and Enterprise MIBs  IF-MIB : RFC 2863  IP-MIB : RFC 4293  CISCO-PRODUCTS-MIB:

M. Bechtel, S. Blümel, A. Quignon27 Cisco Catalyst 2950 SNMP Check MIB-II: RFC 1213 OID: Values: 1, 2, 3 (up, down, testing) Command:  check_snmp -H o C public -c 1:1

M. Bechtel, S. Blümel, A. Quignon28 QUESTIONS