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Installing and configuring Nagios
This is specifically for a Solaris install (I've installed on Solaris 8, 9 and 10 now),
but will probably work for most unixes.
Errors, omissions or questions, please mail to documentation@totkat.org.
| [Preparation] | [Configure apache] |
| [Install Nagios] |
| [Configure host groups] | [Configure hosts] | [Configure contacts] |
| [Configure contact groups] | [Configure commands] | [Configure times] |
| [Configure dependencies] | [Configure escalations] | [Configure resources] |
| [Configure services] | [Configure mail alerts] | [Configure nagios] |
| [Status map] |
| [Testing] |
[Troubleshooting] |
Introduction
Nagios is the new name for NetSaint, a network/service monitoring tool. It was designed
for Linux, but can be compiled and run perfectly well under any UNIX variant as far as I am
aware. The monitoring daemon runs intermittent checks on hosts and services you specify.
These check are performed by using external commands, "plugins", which return status
information to Nagios. When problems are encountered, Nagios can send notifications out to
administrative contacts in a variety of different ways (email, instant message, SMS, etc.).
Current status information, historical logs, and reports can all be accessed via a web browser.
This installation method assumes an existing, working installation of apache. The
guidelines are presented in the order in which it is logical, and sometimes essential, to
proceed with the installation and configuration.
Preparation
Choose whether you want to use Nagios v1.3 or v2.0. There are pros and cons of both, but I would recommend
v2.0(stable) as it is more mature, fixes some of the problems I had in 1.3, supports service groups
as well as host groups and builds in a more forgiving way if you are missing pre-requisites for
certain optional components.
Be root! Make sure anything you'd normally need for compiling and installing stuff is in the
PATH and LD_LIBRARY_PATH variables. Plan where you want to install Nagios ($NAGIOSHOME) and make
a map of your servers and services. Download this little lot and unzip them somewhere sensible,
in my case /export/stage. You may already have some of these installed, but some will need
(re-)configuring.
[There are some lovely extras you can try out, like graphing of historical data, but I've not had a chance to
document any of them yet. Take a look here.]
If you do not already have the gd, jpeg and png libraries installed, unpack them and install
them. Most of those require a simple ./configure and then make and make install. They all contain
basic instructions in the tarballs and are very simple to install. Just don't forget the make
install-lib and make install-headers with the jpeg libraries, otherwise you'll just get cross
when gd refuses to see the jpeg libraries.
As with all guidelines, your mileage may vary. Use common sense, but if you
do hit a wall there are resources on the web if you
Google for "installing Nagios", or you could drop me an email:
documentation@totkat.org and I may be able to help.
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Configure apache
The first thing, before installing Nagios, is to ensure that it is locked down
to unwanted viewers and that apache knows where it is going to be installed. So,
we need to edit apache's configuration, $APACHEHOME/conf/httpd.conf as follows.
We need to add in the script directory for Nagios, making sure that it comes
before your usual cgi-bin definition in the httpd.conf:-
ScriptAlias /nagios/cgi-bin/ "$NAGIOSHOME/sbin/"
Then specify the Nagios base directory after the ScriptAlias definition:-
Alias /nagios/ "$NAGIOSHOME/share/"
Finally, we protect the Nagios install by setting authorisation requirements in the
httpd.conf:-
<Directory "$NAGIOSHOME/sbin">
AllowOverride AuthConfig
order allow,deny
allow from all
Options ExecCGI
</Directory>
<Directory "$NAGIOSHOME/share">
AllowOverride AuthConfig
order allow,deny
allow from all
Options ExecCGI
</Directory>
and setting a username and password for those directories. Firstly create the .htaccess
file in both $NAGIOSHOME/sbin and $NAGIOSHOME/share:-
AuthName "Nagios Access"
AuthType Basic
AuthUserFile $NAGIOSHOME/etc/htpasswd.users
require valid-user
then run:-
$APACHEHOME/bin/htpasswd -c $NAGIOSHOME/etc/htpasswd.users nagiosadmin
where nagiosadmin will be the username given access to Nagios. You will be asked
for a password for that user.
You can now restart apache for those changes
to take effect.
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Install Nagios
Before installing Nagios, we need to create a user and group for the application:-
groupadd nagios
useradd -d $NAGIOSHOME -g nagios -s /bin/false -m nagios
This will create the group and user "nagios", add the user to the group,
create the home directory and Nagios base install directory and make
sure that the user "nagios" cannot log in.
From your staging directory, if you are sure that the jpeg, png and gd
libraries are installed, linked and visible, you first need to configure the
Nagios install. Now, to be absolutely certain that it knows where the gd libraries
are, you will need to specify their location in the options.
./configure --prefix=$NAGIOSHOME --with-nagios-user=nagios --with-nagios-grp=nagios\
--with-perlcache --enable-embedded-perl --with-gd-inc=/usr/local/include\
--with-gd-lib=/usr/local/lib
This should result in no errors, assuming that you have all of the pre-requisites
fulfilled. So, now we can install Nagios from the staging area:-
make all
make install
make install-config
make install-init
This makes the binaries, installs them, installs sample config files and init scripts
into /etc/init.d
Nagios now needs some check plugins installed, because as it stands and unconfigured, it
isn't awfully useful yet.
Head back to your staging directory, untar the plugins tarball and configure them:-
./configure --prefix=$NAGIOSHOME [--with-mysql=<mysql path>*] [--with-pgsql=<postgres path>**]
make
make install
cd $NAGIOSHOME
chown -R nagios:nagios libexec
chown -R nagios:nagios share
* - path to your local mysql if you want to use mysql checking from the Nagios host rather than
using nrpe.
** - path to your local postgres if you want to use postgres checking from the Nagios host
rather than using nrpe.
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Configure Nagios
You now need to configure Nagios
before running it.
Start her up and see what happens!
$NAGIOSHOME/bin/nagios -v $NAGIOSHOME/etc/nagios.cfg
...to check that the .cfg files are good. Then
$NAGIOSHOME/bin/nagios -d $NAGIOSHOME/etc/nagios.cfg
to start and daemonise the process.
Then point your browser at: http://yourserver/nagios/ and
attempt to log in.
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