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If the remote server runs only HTTP and not HTTPS, youll get HTTP CRITICAL Unable to open TCP socket message as shown below. In this tutorial, we'll install Nagios on an Ubuntu 19.10 server, but these steps should work on any Debian-based distro. When Nagios needs to run a scheduled service check, it will initiate the service check and then return to doing other work (running host checks, etc). The plugins can be in any language, Nagios only cares They can be the following: 0: OK And in Puppet agent, I have to define the environment (Dev, Test or Prod). This usually calls for some effort. Learn more. awesome. The plugin returns a CRITICAL state if the service is not started. 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. System Monitoring Via Nagios and SNMP< SNMP snmp is an internet protocol that allows you to retrieve management information from a remote device or to set configuration settings on a remote device. In such cases, only reports regarding hard state changes are propagated across Nagios servers. nagiostats provides statistics of which only the part `Services Ok/Warn/Unk/Crit: 8 / 0 / 0 / 0` are interesting to us, so we are using grep to extract this line. The default FQDN used for testing is www.google.com, but it can be changed as needed. I don't know if it's best practice or not , but i would declare count Warnings as an integer variable when doing arithmetic operations. 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 :). In general, if a check can be done quickly and does not require long running processes, it should definitely be done as an active service. NPCA includes a service module that can check if a service is stopped. By using this website, you agree with our Cookies Policy. How to Install Nagios? The scripts stored in /etc/nagios-plugins/config/ can shed some light on the awesome capabilities of Nagios. On-demand as needed for predictive service dependency checks. In the first case, Nagios takes care of the scheduling, and the command only needs to perform the actual checks and mark the results as OK/WARNING/CRITICAL based on how a check command is configured. Architect and design WAP data flow using BigData Platform. Unlike with active host checks, Nagios does not (by default) attempt to determine whether or host is DOWN or UNREACHABLE with passive checks. Let's consider I have the Nagios server configured to alert only on critical status, so I want an alert if I have too many services on a Warning status. Here is how it can be done. The host status code should be 0 for an UP state, 1 for DOWN and 2 for an UNREACHABLE state. More information on the NSCA addon can be found here. NSClient++ includes a service module that can check if a service is stopped. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? To learn more, see our tips on writing great answers. Nagios Plugins Nagios Plugins does not include a service plugin however the linux-nrpe-agent does provide check_init_service. There are many more services in Nagios which can be used to monitor pretty much anything on the running host. Select check_cluster from the plugin pop-up menu. External applications can submit passive host check results to Nagios by writing a PROCESS_HOST_CHECK_RESULT external command to the external command file. This requires trying to read the entire disk directly from the block device (such as /dev/sda1) and checking if the attempt has failed. sudo usermod -aG docker kifarunix. 2. Nagios provides a sample configuration file, that we will use. We must install this software there to install the "check_nrpe" plugin that we use to perform active checks using the NRPE. ##### # # NAGIOS.CFG - Sample Main Config File for Nagios # # Read the documentation for more information on this configuration # file. In both the cases, the idea is that Nagios receives information about host statuses over the external commands pipe. More information on cached checks can be found here. The performance of on-demand service checks can be significantly improved by implementing the use of cached checks, which allow Nagios to forgo executing a service check if it determines a relatively recent check result will do instead. Nagios Plugins does not include a service plugin however the linux-nrpe-agent does provide check_init_service. Nagios Plugins does not include a service plugin however the linux-nrpe-agent does provide check_init_service. 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. If you don't make use of service dependencies, Nagios won't perform any on-demand service checks. Examples include server load, number of concurrent processes, number of logged in users via NRPE extension. Check HTTP Check whether Apache HTTP is running on a remote server using check_http. It is a protocol that is used in reverse of the other common Nagios protocol NRPE. Contribute to vishalsingh17/GitiPedia development by creating an account on GitHub. Syntax and Options If youve installed Nagios from source, check_httpd command will be located in the /usr/local/nagios/libexec directory. Code-GPT is an extension for VS Code that provides you instant explanations for your code within the code editor using AI. For Nagios to perform active checks when there is no up-to-date result from passive checks, you need to set the check_freshness directive to 1 and set freshness_threshold to the time period after which a check should be performed. Scheduled service checks are run in parallel. Why is there a voltage on my HDMI and coaxial cables? Also, depending on your configuration you should add this last file to the main file (/usr/local/nagios/etc/nagios.cfg): Check the configuration and, if no errors or warnings, reload the service: And now you have a new custom check on a host: Nagios has a huge library of plugins available at Nagios Exchange. In the left navigation pane, select "Process Info" and then "Disable Notifications" and "Commit.". Some methods support checking multiple services at once. It says Unknown option specified in config file , check_http -I 10.0.0.76 -p 8192 url=/MYServiceBus/ post= eregi=.Status_Code.0./Status_Code. When it comes in as a passive check, no state translation is done and Nagios stores the host and all child nodes being down. When max_check_attempts is executed and status of the host or service is still not OK, then hard state is used. To check whether a specific webpage is available, use the -u option as shown below. Fortra's Intermapper vs Kaseya Traverse: which is better? It can also be used by third-party applications running on different machines to send passive check results to a central Nagios server. It only takes a minute to sign up. If you would like to use the whole or any part of this article, you need to cite this web page at Xmodulo.com as the original source. (In this example, the script will print All ok and it will exit with 0, the OK . The check_ncpa.py plugin enables Nagios to monitor the installed NCPAs on the hosts. Here is my configuration : More information on the flap detection logic can be found here. Here is the output when the RemoteAccess service was started: Checking if a service is stopped using SNMP is not very straight forward, checking a process is the best solution here, please refer to the Process Checks KB article. For any support related questions please visit the Nagios Support Forums at: Article Number: 775 | Rating: Unrated | Last Updated by. Nagios also supports a way to monitor hosts and services passively instead of actively. this is THE MOST comprehensive and straight forward turorial I've seen. Nagios can monitor different mail server components like SMTP, POP, IMAP and mailq. It is generally recommended to run the Nagios service check scripts in CLI before adding them to Nagios. It is possible to configure Nagios so that it will receive status information sent over a command pipe. Even the location of the plugins directory is in there. The service check runs in a child process that was fork()ed from the main Nagios daemon. I wrote a plugin in a bash script to check for current Warnings. Nagios understands the following exit codes: These checks can provide useful insight on what is going on within the Nagios server. This increases the security of the database. Detecting and dealing with state changes is what Nagios is all about. This user is then granted all permission to all databases and will be used for monitoring. # Sample object config file for Nagios : 3 # 4 # Read the documentation for more information on this configuration file. The script should then post results to the Nagios daemon. Default is 10 seconds. check_http: command not found. Passive checks require all the logic related to what should be reported and when it should be checked to be put in an external application. You do this with nagios -v command as root: Ensure it returns 0 errors and 0 warnings and proceed to reload the service: After reloading the service, you will see the associated check in the localhost. Copy the configuration file to the Apache directory: /usr/bin/install -c -m 644 sample-config/httpd.conf /etc/apache2/sites-available/nagios.conf Install the Nagios Plugins to have a set of tools to monitor your different services: apt install build-essential libssl-dev gcc Checking a service using SNMP is not very straight forward, checking a process is the best solution here, please refer to the Process Checks KB article. :), I will also menton for new users that using, The debug_levels are binary - 2048 only turns on messages from macros. Pass the specified string as User Agent in HTTP header. Up To: Contents Based on whether the read was successful or not, the appropriate status code, along with plugin output, is sent out. A command to submit passive checks is PROCESS_SERVICE_CHECK_RESULT (visit http://www.nagios.org/developerinfo/externalcommands/commandinfo.php?command_id=114). 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. Nagios can tell what the status of the service is by reading the exit code of the check. The nature of simulating nature: A Q&A with IBM Quantum researcher Dr. Jamie We've added a "Necessary cookies only" option to the cookie consent popup. See Also: Active Checks, Host Checks, Check Scheduling, Predictive Dependency Checks. I take a slightly more brute-force direction than @Zoredache, I login to the nagios server and do "while true; do ps awwlx | grep NAGIOS_CHECK_NAME; done", while I force a re-check of the service, where NAGIOS_CHECK_NAME is either part of the check name or the IP of the server I am looking for. Now let us add check_interval directive. Nagios server in this example is hosted on 192.168..150 and an example client is hosted on IP 192.168..200 Exit Codes To identify the status of a monitored service, Nagios runs a check plugin on it. In order to do this, we need to enable active checks by setting the active_checks_enabled option to 1 without specifying the normal_check_interval directive. Line 1 ##### 2 # Sample object config file for Nagios : 3 # 4 # Read the documentation for more information on this configuration file. If I used the first method, I have to keep separate site.pp for each environment. Active checks reach out from the Nagios host and test if a service is doing what it's expected to do. 1 check_http -p 8083 - user4556274 Jul 29, 2016 at 12:49 Add a comment 3 Answers Sorted by: 3 You can specify the port number directly in the command but you will must create one command per tested port. Last updated on September 22, 2020 by Sarmed Rahman. 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. 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. This yields less output to dig through. This feature is only available to subscribers. 5 check_http examples NSCA stands for Nagios Service Check Acceptor. 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. 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. Making statements based on opinion; back them up with references or personal experience. For example: nagios@nagiosserver:~/ > $ ssh-keygen -t dsa Generating public/private dsa key pair. 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 10.0.2.1 A good example would be a server that is a part of an application, processing job queues using a database. For example . Enable and restart the nrpe service: [user@mon]# systemctl enable nrpe [user@mon]# systemctl restart nrpe. How can I get it to work with https with Nagios4 and plugins 2.x? An external application checks the status on hosts/services and writes the result to External Command File. In this example we are going to define a service and assign it to localhost, because this check is on Nagios itself. Nagios dependencies.cfg example file. To allow it to grow bigger before rotating, add more zeroes, for example. Submitting passive host check results to Nagios requires sending a command to the Nagios external command pipe. The plugin returns a CRITICAL state if the service is not started. These checks are scripts and progams which take input (for example, which host to check, tresholds), do a check and then return an exit code and some performance data. So the Nagios Core version is 3.5.1. How Nagios process handles passive check results can be defined in the main Nagios configuration file. Now in your configuration for checks for a host you can create the following service check. Nagios can tell what the status of the service is by reading the exit code of the check. Check whether Apache HTTPS is running on a remote server using check_http. This tutorial will cover the process of using some of these scripts for checking common services, such as MySQL, Apache web server, DNS, etc. If you are new to the Nagios network monitoring system, see the resources at the Nagios website. I'd like to use the command line to run that particular check and get the output. Nagios check_udp_ports returning critical: result to scheduled check, runs fine manually, Nagios - check procs and --metric=elapsed on the same service. You can create a host file inside the server directory of Nagios and mention the host and service definitions. You'll see the following line inside the /etc/rc.d/init.d/nagios script for the Nagios startup: $NagiosBin -d $NagiosCfgFile Like every Nagios plugin, you will want to check from the command line before adding it to the configuration files. Far better then Nagios documentation. Nagios, the Nagios logo, and Nagios graphics are the servicemarks, trademarks, or registered trademarks owned by Nagios Enterprises. NSClient++ includes a service module that can check if a service is running. Base your decision on 2 verified in-depth peer reviews and ratings, pros & cons, pricing, support and more. A good example of such a test is checking whether there are bad blocks on a disk. This directive is used to perform scheduled checks of the hosts for the number you set; by default it is in minutes. I Have problem with the check_http when I try ur command test , I have the next message : We make use of First and third party cookies to improve our user experience. This is a plugin for Nagios wich you can use to check if a linux service is running. 03-16-2010, 10:31 AM . This task is really easy as Nagios has a built-in command for this. When you restart the Nagios, this host will start getting monitored by Nagios and the specified services will run. The processing of active and passive check results is essentially identical. The flexibility provided by Nagios is perfect for these case scenarios. (If I were running df -h on the linux CLI, I'm using the "h" flag - in the case of the df command, the h stands for "human readable".) Nevertheless, in response to your comment, I don't think there's an error in that, as Bash variables are untyped. rev2023.3.3.43278. Is there a more efficient way to do this? Hi, thanks for your comment. Another difference is that active checks require much less effort to be set up when compared to passive checks. # SAMPLE HOST CHECK . However, applications on remote hosts can't do this so easily. check_command /usr/share/nagios/plugins/check_http -H MYIP -u http://MYIP/test.php, Hi, # Plugin commands (service and host check commands) # Arguments are likely to change between different . If a service is set up with a max_check_attempts directive of 5, then the same number of passive check results would need to be passed in order for Nagios to treat the new status as a hard state change. The key features of passive checks are as follows: The major difference between active and passive checks is that active checks are initiated and performed by Nagios, while passive checks are performed by external applications. Complete a blank sample electronically to Nagios server in this example is hosted on 192.168..150 and an example client is hosted on IP 192.168..200 Exit Codes To identify the status of a monitored service, Nagios runs a check nagios.cfg. How can I make Status Information for Nagios services easier to read? $ vi /usr/local/nagios/etc/servers/devserver.cfg 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. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. The sections below provide examples of how to perform these checks using different methods. To do this: Navigate to Configuration > Command > New. Does anyone have a working example of a dependencies.cfg file for nagios? Nagios also offers another way to work with the statuses of hosts and services. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Remember that the $USER1$ variable, is a local Nagios variable set in the resource.cfg file, in my case pointing to /usr/local/nagios/libexec. The __HOST__ is a special service name, which represents the host check in Nagios. In such cases, Nagios decides when a check is to be performed, runs the check and stores the result. For example sudo gedit /usr/local/nagios/etc/servers/ubuntu_host.cfg # Ubuntu Host configuration file 5 check_http Command Examples 1. In fact, we officially. $ check_http -H 192.168.1.50 HTTP OK HTTP/1.1 200 OK - 332 bytes in 0.004 seconds |time=0.004144s;;;0.000000 size=332B;;;0 2. Check HTTPS Check whether Apache HTTPS is running on a remote server using check_http. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Attributes can be used for both hosts and services. I will leave this script with all the other Nagios plugins inside /usr/local/nagios/libexec/ (This directory may be different depending on your confiugration). The Nagios plugin can be remotely executed on other Linux/Unix machines using NRPE. Thank you for any assistance you can provide. The following is a script that runs the dd system command (visit http://man.linuxquestions.org/index.php?query=dd) to read an entire block device. Passive checks are also used when configuring distributed or redundant monitoring installations. See Also: Active Checks, Service Checks, Host Checks. Try to put full path in the command line. @sunardo I just ran into this exact same thing. The next parameter specifies the number of seconds after which Nagios should consider the results to be out of date.