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1. Welcome to the World of Nagios<< Back to man.ChinaUnix.net
If you're reading this, the chances are that you've heard about Nagios and would like to jump right in and set up a monitoring system. If this is the case, you've come to right place. This document aims to assist users in installing, configuring, extending, troubleshooting and generally getting the most out of your Nagios system.
It must be said that the documentation that ships with Nagios is excellent, and there are many of good tutorials that already exist. This book was written to complement the existing documentation that is already out there, and even go a little further in some areas - especially for the beginners.
For the true beginners in the audience, you'll find I have created a nice set of step by step instructions, walking you through the process of building a server from scratch, installing Nagios and configuring Nagios to monitor a typical network.
Arguably the most useful source of Nagios information is the mailing list nagios-users. This list is frequented by expert Nagios developers and users alike and is *the* place to be if you're serious about Nagios. A great deal of information in this book has been obtained through the help of people on this list, I highly recommend subscribing and participating - to learn, and to help others learn. Almost every Nagios related question I've ever had has been answered and documented in the list archives. It's a good idea to check there before posting.
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2. Useful Nagios Resources<< Back to man.ChinaUnix.net
If the steps contained in this document don’t work for you, or you’re having trouble (in either case, I’d like to know!), you might find the following tutorials helpful.
The complexity of modern networks and systems is somewhat astounding, as any experienced System Administrator will tell you. Even seemingly small networks found in many Small/Medium Enterprises (SME’s) can have extremely high levels of complexity in the systems they run.
Nagios was designed as a rock solid framework for monitoring, scheduling and alerting. Nagios contains some very powerful features, harnessing them is not only a matter of understanding how Nagios works, but also how the system you’re monitoring also works. This is an important realization. Nagios can’t automatically teach you about complex systems, but it will be an valuable tool to help you in your journey.
So what are the sorts of things Nagios can do? Nagios can do much more than this, but nevertheless here’s a list of common things that Nagios is used for.
Check to see if a server is up and running
Notify you if a server is down (by email/pager/SMS)
Check to see if a service is running (mail, http, pop, ssh)
Check to see if a process (or Windows service) is running
Gather performance statistics on a server
Allow specific alerts to only go to particular groups/individuals
Get reports of downtime on your servers
A more technically accurate and complete list of Nagios’ features can be found in the official documentation (http://www.nagios.org/docs/).
The Nagios package doesn’t contain any checking tools (called plugins) at all. Does that statement sound crazy? Sure, but let me explain. Nagios focuses on doing what it does best - providing a robust, reliable and extensible framework for any type of check that a user can come up with.
So how does Nagios perform it’s checking? A huge number of plugins already exist that extend Nagios to perform every type of check imaginable. And if there isn’t an existing check that already exists, you’re free to write your own. The nagios-plugins package is separately maintained and can be downloaded from various sources. We will cover the Nagios plugins later on.
Ethan Galstad is the creator of Nagios. Karl DeBisschop, Subhendu Ghosh, Ton Voon, and Stanley Hopcroft are the main plugin developers. Many other people have contributed to the project over the years by submitting bug reports, patches, ideas, suggestions, add-ons, plugins, etc. A list of some of the contributors can be found at the Nagios website.
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2. Other Monitoring Options<< Back to man.ChinaUnix.net
As with anything, each tool has it’s own set of strengths and weaknesses. Some are the applications may seem similar, but are very different and range from full blown SNMP management solutions, to simple applications with not much flexibility. Big Brother, OpenNMS, OpenView and SysMon (there are dozens more) are often compared to Nagios, however they are quite different in many respects. In my travels as an IT professional, Nagios is the most commonly used monitoring tool by far. There are lots of specialist companies that offer monitoring as a service. A large number of these use Nagios.
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3. Why Use Nagios?<< Back to man.ChinaUnix.net
The Nagios site maintains numerous screenshots that gives you a feel for the interface, however if you’d like to see Nagios in action, I’ve recorded a session where I shutdown an Apache service to simulate a problem. Nagios detects this problem and sends an email alert accordingly. It’s around 5 minutes long and will definitely give you a feel for Nagios.
Watch the demo now! (coming soon)
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Chapter 3. How Nagios Works<< Back to man.ChinaUnix.net
It’s very useful to conceptually understand how Nagios works. The following is a very simplified view on how Nagios works.
Nagios runs on a server, usually as a daemon (or service). Nagios periodically run plugins residing (usually) on the same server, they contact (PING etc.) hosts and servers on your network or on the Internet. You can also have information sent to Nagios. You then view the status information using the web interface. You can also receive email or SMS notifications if something happens. Event Handlers can also be configured to "act" if something happens.
IMAGE
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Chapter 4. Preparing for Installation<< Back to man.ChinaUnix.net
For the cost of hardware these days, I usually recommend running a dedicated server.
One complaint I often here from users (usually new to Linux/Unix or Open Source), is that Nagios is difficult to configure. The Nagios Book aims to dispel this myth, showing you how to build a Nagios server from scratch monitoring several hosts and sending alerts in a matter of hours. Note that it's not a competition when it comes to setting up any server, however I've heard reports of people complaining of taking days and even weeks to set up a Nagios server. This is simply not true, as you will find out!
Please note that this document does not explain the how's and why's of how to build a server, that is beyond the scope of this material. My goal is to try and get users up and running quickly so they can experience the power of Nagios. Having said that, I have created some basic steps to build a FreeBSD server from scratch.
These instructions were written and tested using FreeBSD 6.0, however they should also work just as well on earlier versions. If you're using Linux, some steps may be slightly different. I hope to add steps for each popular distro very soon.
I plan to add some other distro specific information here eventually. If you have installation notes for another platform, I'll gladly add it.
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2. Selecting an Operating System<< Back to man.ChinaUnix.net
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3. Setting Up The Server - FreeBSD<< Back to man.ChinaUnix.net
The FreeBSD project already have a very thorough and complete set of documentation covering how to install FreeBSD. I know the following section is rough, it's only included since it was requested. I highly recommend reading the fine documentation at http://www.freebsd.org/docs.html.
Burn a copy of the boot CD (http://www.freebsd.org).
Reboot with the CD in your drive, make sure your BIOS is set to boot off of CDROM first.
Sysinstall (the FreeBSD System Installer) will run.
Select "Standard"
FDISK Partition Editor - Slices
d - Delete any existing "slices" (any data will be destroyed).
c - Create a new slice, the defaults will be fine.
s - Set that slice to be bootable.
q - Save the changes and quit.
Boot Manager
Select standard, as long as you don't have any other OS' on that disk. This means the disk will boot straight into FreeBSD.
Disk Label Editor
c - Create partitions
a - Use auto defaults (you are free to enter your own values if you wish)
q - Save the changes and quit.
Choose Distribution
Select Minimal.
Install Method?
FTP
Choosing a local mirror. Since you'll be installing via FTP, a quick connection means everything.
Choose Network Card. The default should be ok.
IP 6 = No
Perform as Gateway = No
Enter your network settings here, you must know your gateway (probably your router) and your DNS server (probably provided by your ISP).
SSH = Yes
Inetd = No
DHCP = No
FTP = No
NFS Server = No
NFS Client = No
System Console = No
Time Zone = Yes
Linux Binary Compatibility = No
Mouse = No
Packages = No
Create User = Yes
Exit Install
Remove CDROM and reboot.
Then you MUST install the port tree.
Login as root, then run sysinstall.
Configure > Distributions > Ports (and perhaps the Man pages)
Go grab a coffee!
Make sure you update the locate database (this is mentioned in the next chapter) once the ports are installed, this will make your life much easier.
You now have a fully functioning FreeBSD server with the latest ports ready to be easily installed. I highly recommend that you make sure you keep your FreeBSD system updated.
Upgrading the System
(coming soon)
Portupgrade
(coming soon)
[I'm still working on the most efficient and easiest way to display this]
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4. Useful FreeBSD Commands<< Back to man.ChinaUnix.net
Good, it's running. Now you must add Apache to rc.conf so it's starts at boot time.
ee /etc/rc.conf
Then add:
apache2_enable="YES"
Visit the IP address of your server (i.e. http://192.168.1.10 or whatever IP you used) , you should be greeted with the default Apache welcome page as shown below.
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Chapter 5. Installing Nagios<< Back to man.ChinaUnix.net
OK, so you know all about what Nagios can do, it’s time to get on with it and choose an installation method.
You have two main choices when installing Nagios:
Tarball
Package
For most users, your OS’ native package management tool will be the easiest method of installing Nagios. You will find Nagios in all common package repositories such as RPM, apt-get, Ports etc. Note that some package collections will have several versions of Nagios, you may have to specify which version you want. Most common package collections will be fairly current.
Always consult your package documentation, this will usually contain information specific to your OS (both flavour and version!). No tutorial or guide could possibly cover every version, installation and configuration.
You can download the latest tarball and the RPM’s from:
http://www.nagios.org/download
But wait, if you're using FreeBSD, you don't have to. You can use the Ports Collection.
Tip
The FreeBSD Ports Collection provides an easy way of installing and updating software. Visit www.freebsd.org/docs for more information on using the Ports system.
If you're using another Operating Sytem and you’ve installed Nagios, you may also need to install the Nagios-Plugins package. Using FreeBSD you can install Nagios and the Nagios Plugins package from the ports collection by running the following commands. With previous FreeBSD ports of Nagios, you had to install the plugins separately, now it's all installed at once.
# cd /usr/ports/net-mgmt/nagios/
# make
# make install
# make clean
Note, this will install Nagios version 2 (at the time of writing, it's still in Beta).
I recommend selecting SNMP when prompted as shown below.
If you are using a package management tool, it should be fairly straightforward, but please read the package notes, they are there for a reason. If you're installing from source, read the documentation. It’s very thorough.
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2. Knowing Where Nagios Lives<< Back to man.ChinaUnix.net
One thing I highly recommend (especially for new BSD users) is to update your locate database as described earlier, and run locate nagios. This will show you the exact paths where Nagios is installed. You will need this information later. The following commands will save this information into text files for your reference; perhaps you might find it useful to print them.
Note: If you installed Nagios by a package manager, or it is preinstalled by your distro you may not have to do this step.
Add the following to httpd.conf (your path might be different depending on the OS and version of Apache, remember to use locate if you get stuck):
# ee /usr/local/etc/apache2/httpd.conf
Then copy and paste the text below:
ScriptAlias /nagios/cgi-bin /usr/local/share/nagios/cgi-bin
<Directory "/usr/local/share/nagios/cgi-bin">
AllowOverride AuthConfig
Options ExecCGI
Order allow,deny
Allow from all
</Directory>
Alias /nagios /usr/local/share/nagios
<Directory "/usr/local/share/nagios">
Options None
AllowOverride AuthConfig
Order allow,deny
Allow from all
</Directory>
Please note the paths for FreeBSD are slightly different from the Nagios docs (it's a Linux/BSD thing).
# /usr/local/sbin/apachectl restart
You should now be able to visit the IP/nagios (eg. http://192.168.0.10/nagios) of your server and you should see the Nagios navigation. You will (and should) note that Nagios isn't actually running yet. We still have to configure Nagios.
One the plus side, you should now be able to access the Nagios documentation locally on your Nagios server.
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Chapter 6. Configuring Nagios<< Back to man.ChinaUnix.net
The standard way most people configure Nagios is by simply copying the samples included and modify them with a text editor as needed. Setting up Nagios to monitor even a modest sized network is where most of the work lies. Even though it does take some work, the Nagios configuration files can be "streamlined" using includes and object definitions, this is covered in a separate topic.
I will be covering how to configure Nagios using a text editor. Since we’ll be using FreeBSD, my editor of choice is ee. You can use vi, joe, pico or even Notepad on Windows (via FTP or SCP) if you wish.
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2. Configuration Front Ends<< Back to man.ChinaUnix.net
I'm currently trying several third party tools that exist, below are my initial findings. Keep in mind some of them are early on in development and are a little rough. Some of these tools require extra software on your server and take some work themselves to configure. My instructions don't cover using these tools, but I hope to expand this chapter once I have time to experiment.
Nagmin
Monarch
Monarch is a very slick looking interface for Nagios. I haven't installed it yet, I hope to soon. One appealing factor in choosing this tool would be the excellent documentation.
NagiosWeb
The tool NagiosWeb looks very promising. It uses a MySQL database to store your host/service information, and then writes that to the config files. NagiosWeb adds a few extra menu items to the main Nagios navigation, so access is very handy. I ran into a few problems with the code, so I have abandoned this tool for now. I might come back to it at a later date.
NagioSQL
NagioSQL is another web configuration interface for Nagios. I haven't installed this yet, however it seems to be popular among users.
Simple Config
This is a little PHP application that builds Nagios configurations for you to copy and paste into your config files. Perhaps not as sophisticated as the other options, but it's simple and it works!
If there are any other tools that you come across not listed here, let me know and I'll try to get around to trying them.
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3. Getting Started<< Back to man.ChinaUnix.net
Some people freak out at this part, but this is where the fun starts. It's where you get to configure the actual server and hosts (among other things).
Tip
If you're really against editing the files manually (or have a very large network), there is a Perl script called nmap2nagios.pl that can be downloaded from SourceForge. If you're installing nmap2nagios.pl, you may have to force install the XML::Simple Perl module (well I have to on FreeBSD 5.4, 6.0 and OS X) which is a dependency.
monitor# cd /usr/local/etc/nagios/
monitor# ls -al
total 104
drwxr-xr-x 2 root wheel 512 Nov 7 17:56 .
drwxr-xr-x 6 root wheel 512 Nov 8 12:17 ..
-rw-r--r-- 1 root wheel 30046 Nov 7 17:56 bigger.cfg-sample
-rw-r--r-- 1 root wheel 9569 Nov 7 17:56 cgi.cfg-sample
-rw-r--r-- 1 root wheel 4475 Nov 7 17:56 checkcommands.cfg-sample
-rw-r--r-- 1 root wheel 13602 Nov 7 17:56 minimal.cfg-sample
-rw-r--r-- 1 root wheel 4297 Nov 7 17:56 misccommands.cfg-sample
-rw-r--r-- 1 root wheel 30735 Nov 7 17:56 nagios.cfg-sample
-rw-r--r-- 1 root wheel 1335 Nov 7 17:56 resource.cfg-sample
You will notice that all the config files are there ready to use, all you have to do is rename them to .cfg rather than sample. The structure and use of the config files is covered thoroughly in the Nagios documentation. To keep things simple, we'll be using a basic configuration using the minimal.cfg.
Manually backup files into a separate directory, to reduce clutter and rename the samples to make them the live config files.
Now we have all the files in place, we're almost there. All we have to do is edit a few files to configure our system and to tell Nagios about what we want to monitor. There are only 3 files you need to edit to get a minimal system up and running.
Tip
If you're using FreeBSD, all of the Nagios config files are located in: /usr/local/etc/nagios
###############################################################################
# MINIMAL.CFG
#
# MINIMALISTIC OBJECT CONFIG FILE (Template-Based Object File Format)
#
# Last Modified: 03-23-2005
#
#
# NOTE: This config file is intended to be used to test a Nagios installation
# that has been compiled with support for the template-based object
# configuration files.
#
# This config file is intended to servce as an *extremely* simple
# example of how you can create your object configuration file(s).
# If you're interested in more complex object configuration files for
# Nagios, look in the sample-config/template-object/ subdirectory of
# the distribution.
#
###############################################################################
###############################################################################
###############################################################################
#
# TIME PERIODS
#
###############################################################################
###############################################################################
# This defines a timeperiod where all times are valid for checks,
# notifications, etc. The classic "24x7" support nightmare. :-)
define timeperiod{
timeperiod_name 24x7
alias 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
}
###############################################################################
###############################################################################
#
# COMMANDS
#
###############################################################################
###############################################################################
# This is a sample service notification command that can be used to send email
# notifications (about service alerts) to contacts.
define command{
command_name notify-by-email
command_line /usr/bin/printf "%b" "***** Nagios @VERSION@ *****\n\nNotification Type: $NOTIFICATIONTYPE$\n\nService: $SERVICEDESC$\nHost: $HOSTALIAS$\nAddress: $HOSTADDRESS$\nState: $SERVICESTATE$\n\nDate/Time: $LONGDATETIME$\n\nAdditional Info:\n\n$OUTPUT$" | @MAIL_PROG@ -s "** $NOTIFICATIONTYPE$ alert - $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **" $CONTACTEMAIL$
}
# This is a sample host notification command that can be used to send email
# notifications (about host alerts) to contacts.
define command{
command_name host-notify-by-email
command_line /usr/bin/printf "%b" "***** Nagios @VERSION@ *****\n\nNotification Type: $NOTIFICATIONTYPE$\nHost: $HOSTNAME$\nState: $HOSTSTATE$\nAddress: $HOSTADDRESS$\nInfo: $OUTPUT$\n\nDate/Time: $LONGDATETIME$\n" | @MAIL_PROG@ -s "Host $HOSTSTATE$ alert for $HOSTNAME$!" $CONTACTEMAIL$
}
# Command to check to see if a host is "alive" (up) by pinging it
define command{
command_name check-host-alive
command_line $USER1$/check_ping -H $HOSTADDRESS$ -w 99,99% -c 100,100% -p 1
}
# Generic command to check a device by pinging it
define command{
command_name check_ping
command_line $USER1$/check_ping -H $HOSTADDRESS$ -w $ARG1$ -c $ARG2$ -p 5
}
# Command used to check disk space usage on local partitions
define command{
command_name check_local_disk
command_line $USER1$/check_disk -w $ARG1$ -c $ARG2$ -p $ARG3$
}
# Command used to check the number of currently logged in users on the
# local machine
define command{
command_name check_local_users
command_line $USER1$/check_users -w $ARG1$ -c $ARG2$
}
# Command to check the number of running processing on the local machine
define command{
command_name check_local_procs
command_line $USER1$/check_procs -w $ARG1$ -c $ARG2$
}
# Command to check the load on the local machine
define command{
command_name check_local_load
command_line $USER1$/check_load -w $ARG1$ -c $ARG2$
}
###############################################################################
###############################################################################
#
# CONTACTS
#
###############################################################################
###############################################################################
# In this simple config file, a single contact will receive all alerts.
# This assumes that you have an account (or email alias) called
# "@nagios_user@-admin" on the local host.
define contact{
contact_name chrisb
alias Chris Burgess
service_notification_period 24x7
host_notification_period 24x7
service_notification_options w,u,c,r
host_notification_options d,r
service_notification_commands notify-by-email
host_notification_commands host-notify-by-email
email chris.burgess@nagiosbook.org
}
###############################################################################
###############################################################################
#
# CONTACT GROUPS
#
###############################################################################
###############################################################################
# We only have one contact in this simple configuration file, so there is
# no need to create more than one contact group.
define contactgroup{
contactgroup_name admins
alias Nagios Administrators
members chrisb
}
###############################################################################
###############################################################################
#
# HOSTS
#
###############################################################################
###############################################################################
# Generic host definition template - This is NOT a real host, just a template!
define host{
name generic-host ; The name of this host template
notifications_enabled 1 ; Host notifications are enabled
event_handler_enabled 1 ; Host event handler is enabled
flap_detection_enabled 1 ; Flap detection is enabled
failure_prediction_enabled 1 ; Failure prediction is enabled
process_perf_data 1 ; Process performance data
retain_status_information 1 ; Retain status information across program restarts
retain_nonstatus_information 1 ; Retain non-status information across program restarts
register 0 ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL HOST, JUST A TEMPLATE!
}
# Since this is a simple configuration file, we only monitor one host - the
# local host (this machine).
define host{
use generic-host ; Name of host template to use
host_name localhost
alias localhost
address 127.0.0.1
check_command check-host-alive
max_check_attempts 10
notification_interval 120
notification_period 24x7
notification_options d,r
contact_groups admins
}
define host{
use generic-host ; Name of host template to use
host_name intranet
alias Intranet Server
address 192.168.1.99
check_command check-host-alive
max_check_attempts 10
notification_interval 120
notification_period 24x7
notification_options d,r
contact_groups admins
}
###############################################################################
###############################################################################
#
# HOST GROUPS
#
###############################################################################
###############################################################################
# We only have one host in our simple config file, so there is no need to
# create more than one hostgroup.
define hostgroup{
hostgroup_name test
alias Test Servers
members localhost,intranet
}
###############################################################################
###############################################################################
#
# SERVICES
#
###############################################################################
###############################################################################
# Generic service definition template - This is NOT a real service, just a template!
define service{
name generic-service ; The 'name' of this service template
active_checks_enabled 1 ; Active service checks are enabled
passive_checks_enabled 1 ; Passive service checks are enabled/accepted
parallelize_check 1 ; Active service checks should be parallelized (disabling this can lead to major performance problems)
obsess_over_service 1 ; We should obsess over this service (if necessary)
check_freshness 0 ; Default is to NOT check service 'freshness'
notifications_enabled 1 ; Service notifications are enabled
event_handler_enabled 1 ; Service event handler is enabled
flap_detection_enabled 1 ; Flap detection is enabled
failure_prediction_enabled 1 ; Failure prediction is enabled
process_perf_data 1 ; Process performance data
retain_status_information 1 ; Retain status information across program restarts
retain_nonstatus_information 1 ; Retain non-status information across program restarts
register 0 ; DONT REGISTER THIS DEFINITION - ITS NOT A REAL SERVICE, JUST A TEMPLATE!
}
# Define a service to "ping" the local machine
define service{
use generic-service ; Name of service template to use
host_name localhost, intranet
service_description PING
is_volatile 0
check_period 24x7
max_check_attempts 4
normal_check_interval 5
retry_check_interval 1
contact_groups admins
notification_interval 960
notification_period 24x7
check_command check_ping!100.0,20%!500.0,60%
}
# Define a service to check the disk space of the root partition
# on the local machine. Warning if < 20% free, critical if
# < 10% free space on partition.
define service{
use generic-service ; Name of service template to use
host_name localhost
service_description Root Partition
is_volatile 0
check_period 24x7
max_check_attempts 4
normal_check_interval 5
retry_check_interval 1
contact_groups admins
notification_interval 960
notification_period 24x7
check_command check_local_disk!20%!10%!/
}
# Define a service to check the number of currently logged in
# users on the local machine. Warning if > 20 users, critical
# if > 50 users.
define service{
use generic-service ; Name of service template to use
host_name localhost
service_description Current Users
is_volatile 0
check_period 24x7
max_check_attempts 4
normal_check_interval 5
retry_check_interval 1
contact_groups admins
notification_interval 960
notification_period 24x7
check_command check_local_users!20!50
}
# Define a service to check the number of currently running procs
# on the local machine. Warning if > 250 processes, critical if
# > 400 users.
define service{
use generic-service ; Name of service template to use
host_name localhost
service_description Total Processes
is_volatile 0
check_period 24x7
max_check_attempts 4
normal_check_interval 5
retry_check_interval 1
contact_groups admins
notification_interval 960
notification_period 24x7
check_command check_local_procs!250!400
}
# Define a service to check the load on the local machine.
define service{
use generic-service ; Name of service template to use
host_name localhost
service_description Current Load
is_volatile 0
check_period 24x7
max_check_attempts 4
normal_check_interval 5
retry_check_interval 1
contact_groups admins
notification_interval 960
notification_period 24x7
check_command check_local_load!5.0,4.0,3.0!10.0,6.0,4.0
}
# EOF
cgi.cfg (optional)
Turn off Authentication for the CGI's when getting started. After you can view the web interface and everything is working, then turn Authentication on. This section is totally optional, however it does eliminate authentication problems (which are common for some beginners) during the configuration stage.
Open cgi.cfg and make the following changes:
use_authentication=1
change to
use_authentication=0
Warning
It is a very bad idea to permanently disable authentication. The documentation covers the topic in an incredibly thorough fashion. It is however, worth knowing that this option exists when you're initially configuring Nagios.
resources.cfg
$USER1$=/usr/local/libexec/nagios
You should now be able to run a pre-flight check with success. You should get something like the following.
monitor# /usr/local/bin/nagios -v /usr/local/etc/nagios/nagios.cfg
Nagios 2.0b3
Copyright (c) 1999-2005 Ethan Galstad (www.nagios.org)
Last Modified: 04-03-2005
License: GPL
Reading configuration data...
Running pre-flight check on configuration data...
Checking services...
Checked 6 services.
Checking hosts...
Checked 2 hosts.
Checking host groups...
Checked 1 host groups.
Checking service groups...
Checked 0 service groups.
Checking contacts...
Checked 1 contacts.
Checking contact groups...
Checked 1 contact groups.
Checking service escalations...
Checked 0 service escalations.
Checking service dependencies...
Checked 0 service dependencies.
Checking host escalations...
Checked 0 host escalations.
Checking host dependencies...
Checked 0 host dependencies.
Checking commands...
Checked 8 commands.
Checking time periods...
Checked 1 time periods.
Checking extended host info definitions...
Checked 0 extended host info definitions.
Checking extended service info definitions...
Checked 0 extended service info definitions.
Checking for circular paths between hosts...
Checking for circular host and service dependencies...
Checking global event handlers...
Checking obsessive compulsive processor commands...
Checking misc settings...
Total Warnings: 0
Total Errors: 0
Things look okay - No serious problems were detected during the pre-flight check
You will probably want Nagios to start automatically when your system boots. You do this by editing /etc/rc.conf.
Add Nagios to rc.conf (this means the file /usr/local/etc/rc.d/nagios.sh gets loaded at boot time):
# ee /etc/rc.conf
Then add the following entry:
nagios_enable="YES"
Warning
If you're working on a remote system, be careful editing your rc.conf file. Errors could cause the system to fail to boot. It's happened to me more than once!
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2. The Pre-Flight Check<< Back to man.ChinaUnix.net
It's also worth mentioning that if something goes wrong and you need to make changes, there is no need to restart the server, you can start Nagios manually by running the following command:
You can kill Nagios which will flush the config as an alternative to rebooting. You must replace PID with the actual process ID obtained from ps -aux.
monitor# kill -HUP PID
Running Nagios without any switches displays the following output.
monitor# nagios
Nagios 2.0b3
Copyright (c) 1999-2005 Ethan Galstad (www.nagios.org)
Last Modified: 04-03-2005
License: GPL
Usage: nagios [option] <main_config_file>
Options:
-v Reads all data in the configuration files and performs a basic
verification/sanity check. Always make sure you verify your
config data before (re)starting Nagios.
-s Shows projected/recommended check scheduling information based
on the current data in the configuration files.
-d Starts Nagios in daemon mode (instead of as a foreground process).
This is the recommended way of starting Nagios for normal operation.
Visit the Nagios website at http://www.nagios.org for bug fixes, new
releases, online documentation, FAQs, information on subscribing to
the mailing lists, and commercial and contract support for Nagios.
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3. The –s Switch<< Back to man.ChinaUnix.net
monitor# /usr/local/bin/nagios -s /usr/local/etc/nagios/nagios.cfg
Nagios 2.0b3
Copyright (c) 1999-2005 Ethan Galstad (www.nagios.org)
Last Modified: 04-03-2005
License: GPL
Projected scheduling information for host and service
checks is listed below. This information assumes that
you are going to start running Nagios with your current
config files.
HOST SCHEDULING INFORMATION
---------------------------
Total hosts: 11
Total scheduled hosts: 0
Host inter-check delay method: SMART
Average host check interval: 0.00 sec
Host inter-check delay: 0.00 sec
Max host check spread: 30 min
First scheduled check: N/A
Last scheduled check: N/A
SERVICE SCHEDULING INFORMATION
-------------------------------
Total services: 15
Total scheduled services: 15
Service inter-check delay method: SMART
Average service check interval: 300.00 sec
Inter-check delay: 20.00 sec
Interleave factor method: SMART
Average services per host: 1.36
Service interleave factor: 2
Max service check spread: 30 min
First scheduled check: Mon Nov 21 11:21:52 2005
Last scheduled check: Mon Nov 21 11:26:32 2005
CHECK PROCESSING INFORMATION
----------------------------
Service check reaper interval: 10 sec
Max concurrent service checks: Unlimited
PERFORMANCE SUGGESTIONS
-----------------------
I have no suggestions - things look okay.
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4. Help!<< Back to man.ChinaUnix.net
If Nagios won't start, fear not. Go to the the chapter titled Troubleshooting. If you're still stuck, try asking the nagios-users list. As always, copying the error message into Google usually always pays off.
