In both the cases, the idea is that Nagios receives information about host statuses over the external commands pipe. When everything goes smoothly, we should be able to see our new Nagios client on the Nagios website with its new service OS: unread mail for root, as well as the status green OK. sudo usermod -aG docker kifarunix. NPCA allows you to check multiple services, here is an example that checks for some services that are running and some that are stopped. Previous parts of this book often mentioned Nagios performing checks on various software and machines. In the following example, we are checking whether the website certificate expires in the next 365 days. The example contains partial output. Server Fault is a question and answer site for system and network administrators. The check logic inside Nagios process starts the Active check. Nagios, the Nagios logo, and Nagios graphics are the servicemarks, trademarks, or registered trademarks owned by Nagios Enterprises. As with submitting host check results, it is worth mentioning that Nagios will take some time to process passive check results as they are polled periodically from the external commands pipe. Go to the /usr/local/nagios/libexec dir (assuming you have installed nagios from source, if you have used a package from your distribution, check the docs of your package): $ cd /usr/local/nagios/libexec execute the check_dns plugin with the --help switch. . If you want Nagios to treat all passive check results for hosts as if they were soft results, you need to enable the following option in the main Nagios configuration file: Passive service checks are very similar to passive host checks. Scheduled service checks are run in parallel. How to use it? define service{ use generic-service host_name service_description Uptime check_command snmp_Uptime!-C public } Adjust the commands as required. Asking for help, clarification, or responding to other answers. ##### # Sample object config file for Nagios # # Read the documentation for more information on this configuration file. Nagios can be used to monitor Apache web server as well. This can be done in addition to active checks, to identify critical problems earlier. In order to allow remote hosts to send passive check results to the monitoring host, I've developed the NSCA addon. This website is made possible by minimal ads and your gracious donation via PayPal or credit card. Let us see an example to perform checks on host Consider that you have put your host definitions inside host1.cfg file in /usr/local/nagios/etc/objects directory. You can create a host file inside the server directory of Nagios and mention the host and service definitions. Service status codes are the same as those for active checks0 for OK, 1 for WARNING, 2 for CRITICAL, and 3 for an UNKNOWN state. can nagios adjust its check time based on the status info? Viewed 12725 times since Tue, Nov 14, 2017, Viewed 18667 times since Tue, Nov 28, 2017, Viewed 70502 times since Thu, Nov 9, 2017, Viewed 9709 times since Tue, Nov 14, 2017, Viewed 12197 times since Wed, Nov 29, 2017, Viewed 47389 times since Thu, Nov 9, 2017, Viewed 14647 times since Sun, Nov 26, 2017, Viewed 42173 times since Mon, Nov 13, 2017, Viewed 18034 times since Wed, Nov 15, 2017, Viewed 22586 times since Sun, Nov 26, 2017. check_http -H hostname (or) -I ip-address {optional options}. Enable and restart the nrpe service: [user@mon]# systemctl enable nrpe [user@mon]# systemctl restart nrpe. check_http: command not found. Follow Up: struct sockaddr storage initialization by network format-string, Identify those arcade games from a 1983 Brazilian music video. Far better then Nagios documentation. Last updated on September 22, 2020 by Sarmed Rahman. Nagios server in this example is hosted on and an example client is hosted on IP command line output while running with -S is check_http: Invalid option SSL is not available, Next post: UNIX / Linux whatis Command Examples, Previous post: UNIX / Linux split Command Examples, Home | Linux 101 Hacks Table of Contents | Contact | Email | RSS | Copyright 20092022 Ramesh Natarajan All rights reserved | Terms of Service, host name of the server where HTTP (or HTTPS) daemon is running, Port number where HTTP server runs. This command accepts the host name, service description, status code, and the textual output from a check. Contribute to vishalsingh17/GitiPedia development by creating an account on GitHub. The following is an example of the required configuration for a host that accepts passive checks and has active checks disabled: Configuring services is exactly the same as with hosts. Copyright (c) 1999-2014 Nagios Plugin Development Team <> This plugin tests the HTTP service on the specified host. Check WMI Plus allows you to check multiple services, here is an example that checks for two services that are running. For example sudo gedit /usr/local/nagios/etc/servers/ubuntu_host.cfg # Ubuntu Host configuration file They have a lot of advantages and some disadvantages. See Also: Active Checks, Host Checks, Check Scheduling, Predictive Dependency Checks. Start Nagios Daemon Using nagios -d Typically you would execute "service nagios start" to start the Nagios daemon, which really calls the /etc/rc.d/init.d/nagios script. Hi, this is a fantastic article, i managed to learn how to make plugins myself. The host or the services will be tested again and again till the time the status is permanent. Nagios is a host and service monitor designed to inform you of network problems before your clients, end-users or managers do. Up To: Contents I've: 5 # provided some comments here, but things may not be so clear without further . Services that are checked can be in one of four different states: Service checks are performed by plugins, which can return a state of OK, WARNING, UNKNOWN, or CRITICAL. It allows the implementation of plugins, developed by the community, or even allows us to configure our own monitoring scripts. NSClient++ includes a service module that can check if a service is running. (1)Nagios. Now we know that the custom plugin is working on the client and on the server, and that the NRPE is communicating correctly, we can go ahead and configure Nagios files for checking the remote device. Start the Nagios again. As the Nagios toolsets, including NSCA (Nagios Service Check Acceptor for submitting passive check results to the Nagios core server) and NRPE (Nagios Remote Plugin Executor for accepting active check requests from the Nagios core server and send back the results), were initially only developed for Unix-based and Linux Operating Systems, Filters such as firewall and TCP wrappers should be used. Base your decision on 2 verified in-depth peer reviews and ratings, pros & cons, pricing, support and more. To allow it to grow bigger before rotating, add more zeroes, for example. This is the main configuration file of Nagios core. For example, to set up a very similar service, all we need to do is to use the same parameters as those for the hosts: In this case, Nagios will never perform any active checks on its own and will only rely on the results that are passed to it. If an application that resides on the same host as Nagios is sending passive host or service check results, it can simply write the results directly to the external command file as outlined above. The following is a script that runs the dd system command (visit to read an entire block device. On a finishing note, Nagios can monitor many other sectors of a network. define service{, Go to your plugin directory - in my example it is, Type you plugin name - in my example it is, now run the full command - (plugin name) -H (hostname) -p (port number), However in this example port number is optional, in your config file which is look something like below (myserver.cfg) and you want to run check_cpu from command line, to check instantly (without GUI green or red), Try this - (plugin full path) - H (servername) -c (checkname). Minimum number of days a SSL certiface must be valid. This setting will expose MySQL to all available interfaces, including WAN. It only takes a minute to sign up. How to install and configure nagios on centos 7 step by step ile ilikili ileri arayn ya da 22 milyondan fazla i ieriiyle dnyann en byk serbest alma pazarnda ie alm yapn. The following is an example of the required configuration for a host that accepts passive checks and has active checks disabled: define host { use generic-host host_name linuxbox01 address Nagios comes with a wide range of built-in scripts for monitoring services. Sometimes I find it tricky figuring out exactly what a plugin is doing. Let us see an example to perform checks on host . So if you wanted to run the check_http check from the CLI, you would run ./check_http -I, where the I flag stands for the IP Address (, I struggled to get this to work, not sure what i was doing wrong (noob) but the debug_level trick worked for me :). A good example would be a server that is a part of an application, processing job queues using a database. It is vital to make sure only legitimate networks have access to the database. Code-GPT is an extension for VS Code that provides you instant explanations for your code within the code editor using AI. While Nagios can monitor multiple OSes, the server must reside on a Linux or Unix variant such as FreeBSD or Solaris. Set enable_notifications=0 in nagios.cfg. Now let us add check_interval directive. Does anyone have a working example of a dependencies.cfg file for nagios? NPCA includes a service module that can check if a service is stopped. When defining and testing new services in nagios I have been restarting nagios, then clicking the service, and rescheduling a check for as soon as possible, then waiting until the check happens. Agree In such a case, adding a module that reports current utilization along with the OK/WARNING/CRITICAL state to Nagios seems much easier than using active checks for the same job. The following directive allows it: Setting up hosts or services for passive checking requires an object to be defined and set up so as not to perform active checks. Up To: Contents Add the file to the standard Nagios Core location, /usr/local/nagios/libexec. Attributes can be used for both hosts and services. Now that the syntax is available, TCP port 80 can be checked as follows. Often, there are situations where active checks obviously fit better. In such cases, Nagios decides when a check is to be performed, runs the check and stores the result. For example, a plugin which returns a WARNING state will cause a service to have a WARNING state. 2. On-demand checks are performed as part of the predictive service dependency check logic. This cant be done as an active check as reading the device takes a lot of time to completelarger disks might require several hours to complete. Check HTTP Check whether Apache HTTP is running on a remote server using check_http. What can a lawyer do if the client wants him to be acquitted of everything despite serious evidence? . The line should look like: Define the standard checks that you will perform on every client with NRPE. External applications can submit passive service check results to Nagios by writing a PROCESS_SERVICE_CHECK_RESULT external command to the external command file. This tutorial will cover the process of using some of these scripts for checking common services, such as MySQL, Apache web server, DNS, etc. Based on whether the read was successful or not, the appropriate status code, along with plugin output, is sent out. Plugin then gets executed on the remote machine where is collects the required information and sends then back to Nagios daemon. thank you! Once the host and services are configured on Nagios, checks are used to see if the hosts and services are working as they are supposed to or not. The main Nagios process then handles the check results and takes appropriate action (running event handlers, sending notifications, etc.). It says Unknown option specified in config file , check_http -I -p 8192 url=/MYServiceBus/ post= eregi=.Status_Code.0./Status_Code. When Nagios plans and receives results from active checks, it takes the actual network topology into consideration and performs a translation of the states based on this. More information on the flap detection logic can be found here. This can cause problems if you are submitting passive checks from a remote host or you have a distributed monitoring setup where the parent/child host relationships are different. The check_init_service plugin does not support checking multiple services. What is check_http? Nagios dependencies.cfg example file. Yeah, it's totally brute-force, but it works for me. Submitting Passive Check Results From Remote Hosts. Check whether Apache HTTPS is running on a remote server using check_http. Yup, just like any other linux flag, the "-" with whatever flags you use will load the flag. Complete a blank sample electronically to The following diagram shows how both active and passive checks are performed by Nagios. Learn more about Stack Overflow the company, and our products. More information on dependencies can be found here. When it comes to checking MySQL, it should be kept in mind that MySQL, by default, listens on only the loopback interface Active checks reach out from the Nagios host and test if a service is doing what it's expected to do. The next parameter specifies the number of seconds after which Nagios should consider the results to be out of date. You'll see the following line inside the /etc/rc.d/init.d/nagios script for the Nagios startup: $NagiosBin -d $NagiosCfgFile Connect and share knowledge within a single location that is structured and easy to search. Next, update the remote Docker daemon DNS details on your hosts file if there is no local DNS; sudo tee -a " docker01" >> /etc/hosts. The object file localhost.cfg allows for parameters to be passed to check_ssh. Depending on the status received on hosts and services, appropriate action is taken. By using this website, you agree with our Cookies Policy. If the remote server runs only HTTP and not HTTPS, youll get HTTP CRITICAL Unable to open TCP socket message as shown below. First you should define a command in the commands.cfg file. November 2012, by Simon Krenger. UNKNOWN 2013-04-25 18:11:24 0d 0h 55m 37s 4/4 RESPONSE: UNKNOWN ERROR: /usr/bin/nc does does not exist, i am really getting frustrate from this nagios error, nitin: you need to install the netcat package for your distribution which will provide /usr/bin/nc, I had been using this plugin for a while. This will give an idea on whether the execution will be successful and what the output of the script will look like. You might also want to give the 'capture' plugin a try. The Nagios Service Check Acceptor (NSCA ) addon has historically been the addon of choice for Nagios administrators that need to establish data feeds or passive check transmission between Nagios installations. So the Nagios Core version is 3.5.1. This file location depends on the configuration you've done, in my case it is in /usr/local/nagios/etc/objects/commands.cfg. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The time performed is specified in seconds. Xmodulo 2021 About Write for Us Feed Powered by DigitalOcean, Creative Commons Attribution-ShareAlike 3.0 Unported License, Monitor whether MySQL is running by checking port, Monitor the availability of certain database. For Nagios, many, many Oracle plugins are available for checking database availability and performance. Treat NRPE connection failures as 'UNKNOWN' service state, and don't notify on UNKNOWN services . These will come through as an Unconfigured Object initially because Nagios XI has never received a Passive check result for this host/service. The following illustration shows how results from active and passive checks are treated differently by Nagios: In both the cases, a check result stating that the host is down is received by Nagios. Find the plugin you want to run (if you're not sure, compare what you see in your plugins directory on your Linux box with the plugins located here:, or try running "./plugin-name -h" to get the help info about the plugin). Fortra's Intermapper vs Kaseya Traverse: which is better? Passive checks are performed by external processes and the results are given back to Nagios for processing. Does ZnSO4 + H2 at high pressure reverses to Zn + H2SO4? Does a summoned creature play immediately after being summoned by a ready action? Edit the /usr/local/nagios/etc/objects/localhost.cfg file and add the following block: Now we are all set, the only thing pending is reloading Nagios to read the configuration files again. this is THE MOST comprehensive and straight forward turorial I've seen. JOB, We want Nagios to monitor this database, and as the application is already using it, we can add a module that reports this to Nagios. The module defines a "good" service as one that is running and a "bad" service is one that is not running, so you can define critical is when more than 0 "good" services exist. Once the host and services are configured on Nagios, checks are used to see if the hosts and services are working as they are supposed to or not. These checks can provide useful insight on what is going on within the Nagios server. It is possible to configure Nagios so that it will receive status information sent over a command pipe. Syntax and Options In this tutorial, the following three servers are being used. Service or Daemon checks are system processes that run in the background, usually configured to start when the system boots. Affordable solution to train a team and make them project ready. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Why is there a voltage on my HDMI and coaxial cables? But today when I am trying to post an XML message to the server, from console it works well but does not work with nrpe. The first thing that needs to be done in order to use passive checks for your Nagios setup is to make sure that you have the following options in your main Nagios configuration file: It would also be good to enable the logging of incoming passive checksthis makes determining the problem of not processing a passive check much easier. These types of checks are called Active Checks. Related Commands. For HTTPS running on a different port, do the following. There are several different use cases covered in this KB article: The sections below provide examples of how to perform these checks using different methods. This requires trying to read the entire disk directly from the block device (such as /dev/sda1) and checking if the attempt has failed. This command accepts the host name, status code, and the textual output from a check. In fact, we officially. You never know how many (if any) traps or alerts you'll receive in a given time frame, so it's not feasible to just monitor their status every few minutes.