Top Nagios Interview Questions (2021) | CodeUsingJava
















Most frequently Asked Nagios Interview Questions


  1. What is Nagios?
  2. What are the features used in Nagios?
  3. Explain Nagios Architecture?
  4. What are the Products used in Nagios?
  5. What are Plugins?
  6. What are the Types of Nagios Plugins?
  7. What is NRPE?
  8. What are some of the databases supported by monitoring of Nagios?
  9. How can we use Nagios to monitor a Log File?
  10. How do we monitor Elasticsearch by using Nagios?
  11. How can we parse Nagios status.dat File?
  12. What are the Types of Nagios State?
  13. What is Ndoutils?

What is Nagios?

Nagios is used in monitoring all the tools which are used in Continuous Monitoring of Applications, Systems, Services, and Business Processes, etc in DevOps Culture. Nagios also helps in alerting all technical staff about the problem, by allowing the staff to begin with the Remediation Process before it affects end-users, business process and customers.
Nagios report any changes and reports it to the technical staff, by using Nagios we do not need to explain why an unseen infrastructure can affect our organization's Bottom Line.
Nagios Interview Questions

What are the features used in Nagios?

Features used in Nagios are as follows:
  • Monitoring - Nagios allows in easy monitoring of in-house and in services, systems, etc.
  • Visibility and Awareness - Nagios helps by providing Centralized View of the monitored IT Infrastructure.
  • Problems Remediation Alert - Nagios helps by providing communication on all known problem and issues response.
  • Reporting - Nagios helps in ensuring SLAs and in providing alerts, alert response and notifications.
  • Code - Nagios gives full access to the source code.

Explain Nagios Architecture?

Nagios Interview Questions
Nagios Server are installed on remote servers which can be monitored.
Nagios helps in sending singnals through the scheduler for running the plugins on the servers.
Plugins helps in collecting data and sending it to the scheduler.
Lastly the process schedules send the notifications and updates Nagios GUI.

What are the Products used in Nagios?

Nagios Interview Questions
Products used in Nagios are as follows:
  • Nagios Network Analyser - helps in containing the potential threats on the network so the admin will take quick actions.
  • Nagios Fusion - helps in providing a centralized view of the Monitoring System. We can set up separate monitoring servers for different geographies.
  • Nagios Log Server - helps in searching logs of data very easily and keeps them at one location containing a high availability setup.
  • Nagios Log Server - helps in monitoring IT infrastructure and is based on Nagios Core.
  • Nagios XI -helps in monitoring complete IT Infrastructure components such as network, applications, services, and operating systems.

What are Plugins?

Plugins are used in monitoring Databases, Applications, Network Equipment, Operating Systems, etc protocols with Nagios. They have compiled executables that help in extending Nagios functionality for monitoring hosts.
Nagios then executes Plugin for checking the status of the service and supports embedded Perl interpreter for executing Perl Plugins.

What are the Types of Nagios Plugins?

There are 3 types of Nagios Plugins:
Official Nagios Plugins are used and maintained by the official nagios plugins team.
Community Plugin are developed by the Nagios community members.
Custom Plugins is used in writing our own custom Plugins.

What is NRPE?

Nagios Remote Plugin Executor(NRPE) helps in running remote Linux, UNIX Workstation. These are used for monitoring CPU Load and Memory utilization on remote machines.NRPE Agent is installed on the remote devices for the following purposes.

What are some of the databases supported by monitoring of Nagios?

Databases supported by Nagios are:
MySQL
Postgres
Oracle
Microsoft SQL software

How can we use Nagios to monitor a Log File?

We can monitor logs with Nagios by using log checker that will return a warning only for the discovered error messages.
We can also use the following command for the following:
max_check_attempts              3
is_volatile                     3


How do we monitor Elasticsearch by using Nagios?

We can manage elasticsearch by using nrpe and Cluster Health API.We can also use the following command:
command[check_elastic]=/usr/local/nagios/libexec/check_http -H localhost -x /_cluster/health -p 9200 -w 2 -c 3 -s green


How can we parse Nagios status.dat File?

We can parse status.dat file for Nagios and the output will be as XML with Python Script.
def parseConf(source):
    conf = {}
    patID=re.compile(r"(?:\s*define)?\s*(\w+)\s+{")
    patAttr=re.compile(r"\s*(\w+)(?:=|\s+)(.*)")
    patEndID=re.compile(r"\s*}")
    for line in source.splitlines():
        line=line.strip()
        matchID = patID.match(line)
        matchAttr = patAttr.match(line)
        matchEndID = patEndID.match( line)
        if len(line) == 0 or line[0]=='#':
            pass
        elif matchID:
            identifier = matchID.group(1)
            cur = [identifier, {}]
        elif matchAttr:
            attribute = matchAttr.group(1)
            value = matchAttr.group(2).strip()
            cur[1][attribute] = value
        elif matchEndID and cur:
            conf.setdefault(cur[0],[]).append(cur[1])              
            del cur
    return conf


What are the Types of Nagios State?


Nagios Interview Questions

What is Ndoutils?

Ndoutils helps in storing all configuration and the event data from Nagios in one database. Ndoutils is also used for storing all the information from Nagios in a database that allows for quicker retrieval and processing of data and also in helping serve as a foundation for developing PHP-based Web Interface.