Is your configuration verification failed in Nagios? We can help you fix it.

Here at Bobcares, we have seen several such Nagios-related issues as part of our Server Management Services for web hosts and online service providers.

Today we’ll take a how to fix this Nagios error.

Know more details about why configuration verification failed in Nagios

Recently, we had a customer who received the below error message in Core Configuration Manager (CCM), when he Apply Configuration.

Configuration verification failed.

An error occurred while attempting to apply your configuration to Nagios Core. Monitoring engine configuration files have been rolled back to their last known good checkpoint.

Then when clicking the Show Errors link, a message displays. This message indicates the problem in the config files along with a line number for the config file. However, when looking at the config file in a text editor, the line number does not appear to relate to the problem.

Error: Service has no hosts and/or service_description (config file ‘/usr/local/nagios/etc/services/centos01.cfg, starting on line 32)

Here is the process of Apply Configuration.

• First, the new config files are temporarily written to disk
• Next, Nagios verifies the config files are valid or not.
• Then temporary config files are made permanent
• Finally, we restart the Nagios service.

If the verification step fails then the temporary files are discarded. In the file, when we check the line number it references, it is not valid as the temporary files no longer exist.

What to do when configuration verification failed in Nagios

We saw the error message in detail. Now let us see how our Support Engineers resolve this error message.

Here are the steps that we follow to force the config files to be written to the disk.

• First, we open the CCM.
• Next, we access Tools >> Config File Management
• After that, we click the Delete Files button. It will display “Successfully deleted all Host/Service Config Files”
• Then, we click the Write Configs Button. It will show an output containing all the files it creates.
• We click the Verify Files button
• As a result, the output should end with the error message.

At this point, we open an SSH session to the Nagios XI server. And open the file in a text editor to investigate the problem.

Generally, the error message explains the problem, in this example, the below error message appears:

Service has no hosts and/or service_description (config file ‘/usr/local/nagios/etc/services/centos01.cfg’, starting on line 32)

Through this, we can determine that it is a config of service for centos01.

For this specific problem, there was no host assigned to the service. After updating the service in CCM, following the Write and Verify steps above, the verification process should succeed.

It is possible that there are multiple config errors for different objects. So we will need to keep repeating the above process until the Verify is successful.

After the Verify is successful:

• Quick Tools > Apply Configuration
• Click the Apply Configuration button

[Need any further assistance in fixing Nagios errors? – We are here to help you]

Conclusion

Today, we saw the solution our Support Engineers provide a solution this Nagios problem.