How to Monitor Memcached Service with Nagios
by Prashant · Published · Updated

Monitor Memcached Service with Nagios
In this article, we are going to learn how to monitor the Memcached service with the Nagios application.
I hope you already install the Nagios server and NRPE Service. If not or you are new who just started working on Nagios then refer to the below links which help you to clear your doubts regarding Nagios Application.
With the default, Nagios installation will provide only some basics plugins which helps to monitor the general/standard services and application on the server.
In such a case, we need to install custom plugins that help us to monitor particular services and applications on Server.
What is Memcached?
Memcached is a very important part of the caching mechanism. It will help to improve the speed of your website as well as performance. It is our duty to keep an eye on services that are running properly or not.
Nagios will help us with the custom plugin that can monitor the Memcached service.
Below are the important parameters we are going to monitor about Memcached:
- Total-free-memory
- Current_items
- Current_connections
- Total_connections
- Limit_maxbytes
Configuration of Custom Memcached Plugin
Step 1: Install dependency packages
To run the custom plugin of Memcache you need to first install the dependency package on the server which supports the Memcached plugin.
Run below command to install package,
$ apt-get install libcache-memcached-perl
Step 2: Download Custom Memcached Plugin
Now download the Memcache custom plugin which is used to fetch or monitor Memcache service on the host server.
Download Plugin and paste it to below path,
$ cd /usr/local/nagios/libexec
$ wget https://www.linuxgrow.com/wp-content/uploads/check_memcached.pl.zip
Step 3: Give Permissions
Give executable permission to check_memcached.pl plugin using the below commands,
$ chmod +x check_memcached.pl
Step 4: Configure Memcached Plugin
Open file “nrpe.cfg” which basically resides under /etc/nagios directory.
Add below Memcached monitoring command which helps to fetch information from the host server and send it to the Nagios server.
vim /etc/nagios/nrpe.cfg
command[check_memcached]=/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip -p 11211 -t ping
command[check_memcached_threads]=/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip –threads=WARN:5,CRIT:8
Save and close the file.
You can also use the below parameters for monitoring use threshold values of warning and critical as per your requirement.
/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip --total_free=WARN:value,CRIT:value
/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip --curr_items=WARN:value,CRIT:value
/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip --total_connections=WARN:value,CRIT:value
/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip --curr_connections=WARN:value,CRIT:value
/usr/local/nagios/libexec/check_memcached.pl -H memcached-ip --limit_maxbytes=WARN:value,CRIT:value
Note: To check some other parameters with their threshold values use the below help command.
/usr/local/nagios/libexec/check_memcached.pl -help
Step 5: Configuration on Nagios Server
Now come to Nagios server and go to the “/usr/local/nagios/etc/” directory. Create a file under the remote host directory which I already explained in the previous article.
For more understanding refer link,
Here i have created file in “/usr/local/nagios/etc/clients” directory with name of “memcached-service-hosts.cfg”.
vim /usr/local/nagios/etc/clients/memcached-service-hosts.cfg
define service {
use generic-service
host_name nagios_host
service_description Memcached Processes
check_command check_nrpe!check_memcached
}
define service {
use generic-service
host_name nagios_host
service_description Memcached Memory Usage
check_command check_nrpe!check_memcached_threads
}
Save and close the file.
Step 6: Verify Configuration & Restart Nagios Service
Give permission to created files and restart the nrpe and Nagios service.
$ chown -R nagios.nagioscmd memcached-service-hosts.cfg
$ /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg
$ /etc/init.d/nagios-nrpe-server restart
$ /etc/init.d/nagios restart

If you’re facing any difficulties while configuring Memcached service monitoring. Please do comment on your queries or problem via the comment section, till then stay tuned to Linuxgrow.com for more such valuable articles.
Thank You 🙂