Nagios Interview Questions

Nagios Interview Questions and Answers

Do you think you can ace the Nagios Interview? Are you sure you are prepared? If you are not, let us help you ace it. We have compiled a list of questions that you may be asked in the interview. Read on to know if you can answer all of them.

Q1) What exactly is Nagios?

Ans: A monitoring program called Nagios is used to keep an eye on business processes, applications, and system functions continuously. The Nagios tool can inform the technical team of any malfunction and issue. As a result, technical team members or DevOps experts can start the necessary remediation operations before any adverse effects on business processes, clients, or end-users. In these situations, the team is not required to explain to anyone why an undetected infrastructure breakdown affects the organization's bottom line.

Q2) Mention a few features of Nagios?

Ans. There are numerous features in Nagios.

• The monitoring of many systems, infrastructures, and applications is made possible through its APIs.
• It features extras that help you plan renovations and alert you to the infrastructure's deterioration.
• Its code is completely accessible to you because it is open-source software.
• It has a quick and flexible reporting system. It provides you with a list of every alert and every response to it.
• Nagios allows you to see both the specific information about anything and the complete infrastructure of your company.
• More than a million people use Nagios, which has a large user base. You can ask them for assistance if you run into any issues or have any inquiries; they'll be pleased to do so.

Q3) How is Nagios put to use?

Ans: Uses of Nagios:

• On a server, Nagios functions as a service.
• It makes connections with hosts on the network by running plugins on the server.
• Through this interface, you can view the linked host's complete information.
• In the event that a problem emerges, you would be notified via email or another method.
• Nagios executes scripts at predetermined intervals and stores the output of those scripts.
• Nagios begins executing other scripts if the outcomes of running the scripts change.

Q4) What exactly is Nagios "Plugins"?

Ans: Different scripts that verify the status of a service or host are known as plugins in the Nagios system. The command line would be used to carry them out.To determine the state of the many hosts and services that are present in your network, Nagios examines the output from its plugins.

Q5) Why is Nagios a necessary tool?

Ans: The following are some key considerations for using the Nagios monitoring tool:

• It identifies any kind of server or network issues.
• It helps consumers identify the problem's underlying causes so they can find a long-lasting solution.
• Continuously keep an eye on the entire infrastructure and commercial operations.
• It can be used by users to track and resolve issues with server performance.
• It helps us to schedule infrastructure improvements prior to the failure of dated systems.
• Even better, users may keep the service's security and accessibility.
• Resolve issues proactively when in a crisis.

Q6) What is Nagios Infrastructure?

Ans. Client-server architecture is the foundation of Nagios. A Nagios server is usually operating on a host in a network, and plugins are running on all distant computers that need to be monitored.

• The Nagios server contains the scheduler. The remote host receives a signal from this to start the plugins.
• The remote host provides the status of the plugin.
• The process scheduler receives the data from the plugin.
• The process scheduler changes the GUI and notifies administrators as well.

Q7) Explain the Nagios Plugins

Ans. Nagios Plugins are independent add-ons that Nagios Core can use to monitor virtually anything. The command-line parameters are processed by plugins, which then perform a particular check and submit the findings to Nagios Core.

Utilizing Nagios to monitor devices, hosts, protocols, applications, and services are made possible through plugins.

Q8) What does Nagios' NCPA mean?

Ans: NCPA is referred to as Nagios Cross-Platform Agent. A plug-in for Nagios Core is available for download. Despite the fact that Nagios XI is not necessary for this agent, it does have a wizard for creating active checks with NCPA.

Q9) Explain NRPE.

Ans: The Nagios Remote Plugin Executor, often known as NRPE, enables the use of remote Linux or UNIX workstations. With the aid of these plugins, remote workstations can be monitored for CPU and memory usage as if they were local resources. The NRPE agent is installed on distant devices for this purpose since it is required because this information is rarely publicly accessible to an external system.

Two components make up the NRPE add-on or plugin, and they cooperate to carry out the task:

• A local machine plugin used for monitoring is called check_nrpe.
• Runnable on distant machines is the NRPE daemon.

Q10) What different kinds of checks does Nagios perform on hosts and services?

Ans: There are two different sorts of checks that Nagios performs on hosts and services i.e. Active and Passive checks

• Active Checks: The Nagios process starts active checks, which then run according to an established schedule. To monitor remote hosts and services, Nagios runs plugins and passes information about what needs to be examined.
• Passive Checks: Applications and processes from outside sources start and carry out passive checks. The findings of the passive check are subsequently sent to Nagios for additional processing. Active checks are started and carried out by Nagios, whilst passive checks are carried out by external programs. This is the primary distinction between active and passive checks.

Q11) What is the Nagios protocol for sending passive checks?

Ans. To allow distant hosts to submit passive check results to the monitoring host, we may utilize the NSCA or NRDP addons. A daemon that operates on Nagios Core hosts and a client that runs on distant hosts make up the NSCA addon.

Q12) What do SOFT and HARD states entail?

Ans: Soft and hard states can be described as:

• Even if the service check has not been rechecked beyond the number of times set by the max check attempts directive, the results of the host or service checks in the event of the SOFT state are not OK or up to par. Soft Recovery is the process of recovering a component from such a soft error.
• Hard errors occur when a host or service check result is not "OK" and it has been tested more than the number of times allowed by the max check attempts directive in the host specification. Hard Recovery is the process of recovering any service from this problem.