Depending on the status received on hosts and services, appropriate action is taken. 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. The following line is commented out to make MySQL listens on all interfaces. Be aware that the service module is cAsE SeNsative, you can overcome this with the match= argument. Nagios executes event handlers to handle hard states. This way, the other applications on your Nagios server can report the status of the hosts. 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. In order to make Nagios treat passive host check results in the same way as active check results, we need to enable the following option: By default, Nagios treats host results from passive checks as hard results. Active checks can be used to "poll" a device or service for status information every so often. An example shell script of how to submit passive service check results to Nagios can be found in the documentation on volatile services. The default FQDN used for testing is www.google.com, but it can be changed as needed. This requires trying to read the entire disk directly from the block device (such as /dev/sda1) and checking if the attempt has failed. 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. How to Write a Custom Nagios Check Plugin, /usr/local/nagios/etc/objects/commands.cfg, /usr/local/nagios/etc/objects/localhost.cfg, /usr/lib/nagios/plugins/check_users -w 5 -c 10, /usr/local/nagios/etc/objects/nrpeclient.cfg, Generic installation on Debian-based Client, Set the NRPE Check on the Server Configuration Files, Develop Network Applications for ESP8266 using Mongoose in Linux, How to Setup IKEv2 IPSec VPN Using strongSwan and Let's Encrypt on Rocky Linux 9, ISPConfig Perfect Multiserver setup on Ubuntu 20.04 and Debian 10, Generating Web Site Statistics With AWStats & JAWStats On Debian Lenny, How to Install Jitsi Video Conference Platform on Debian 11, How to Install LAMP Server Stack on Ubuntu 22.04, How to use grep to search for strings in files on the Linux shell, You have Nagios installed and running (You can follow this. If you would like to disable passive checks for just a few hosts or services, use the passive_checks_enabled directive in the host and/or service definitions to do so. This plugin uses systemctl is-active command, please check you have systemd. First, the servers are defined in Nagios. Periodically when these checks are processed, notifications or alerts are sent depending on the information in check result. These will come through as an Unconfigured Object initially because Nagios XI has never received a Passive check result for this host/service. The service check runs in a child process that was fork()ed from the main Nagios daemon. Here is another example to check CPU: nagios will indicate warning if the % cpu utilized by any process is greater than 70% and will indicate critical alert if the % cpu is greater that 80% vegan) just to try it, does this inconvenience the caterers and staff? From the GroundWork Monitor menu, selecting Configuration > Nagios Monitoring > Services > Service Templates presents the options New, Copy, and Modify. The NRDP addon allows administrators to migrate from using NSCA to NRDP fairly easily. JOB, Active checks are initiated by Nagios process and then run on a regular scheduled basis. For example, you can use the 'check_http' plugin to verify that a web server is running, is returning the right text, or has an up-to-date SSL certificate. 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. Code-GPT is an extension for VS Code that provides you instant explanations for your code within the code editor using AI. 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. As mentioned earlier, server-2 has postfix mail server set up on it. Note: A service must be defined in Nagios before you can submit passive check results for it! Then we are removing spaces using sed and finally cut the appropriate field using cut, i this case field 5 is what we want. ##### # Sample object config file for Nagios # # Read the documentation for more information on this configuration file. It shows what is performed by Nagios in both cases and what needs to be done by the check command or an external application for passive checks. Plugin then gets executed on the remote machine where is collects the required information and sends then back to Nagios daemon. Scheduled service checks are run in parallel. Nagios provides a sample configuration file, that we will use. Get your subscription here. Nagios Core is an Open Source system for monitoring hosts, networks and services. Like every Nagios plugin, you will want to check from the command line before adding it to the configuration files. Making statements based on opinion; back them up with references or personal experience. define service{ use generic-service host_name web1.onemetric.com.au service_description Uptime check_command snmp_Uptime!-C public } Adjust the commands as required. Here is an example set of passive checks that . What is check_http? Agree Browse other questions tagged, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site. Passive checks are useful for monitoring services that are: Examples of asynchronous services that lend themselves to being monitored passively include SNMP traps and security alerts. this is THE MOST comprehensive and straight forward turorial I've seen. There are many more services in Nagios which can be used to monitor pretty much anything on the running host. TRUST_EXIT_CODE=0 usage () { cat <<EOF This task is really easy as Nagios has a built-in command for this. Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. The following file can be modified to do the job. In such cases, Nagios decides when a check is to be performed, runs the check and stores the result. On-demand service checks are also run in parallel if needed. Affordable solution to train a team and make them project ready. When a passive result check comes in to Nagios, Nagios expects that the result already has a network topology included. If the remote server runs only HTTP and not HTTPS, youll get HTTP CRITICAL Unable to open TCP socket message as shown below. thanks! Thanks for contributing an answer to Server Fault! 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. For example: nagios@nagiosserver:~/ > $ ssh-keygen -t dsa Generating public/private dsa key pair. In this tutorial, the following three servers are being used. In most cases you'll use Nagios to monitor your hosts and services using regularly scheduled active checks. Nagios comes with a wide range of built-in scripts for monitoring services. A user [emailprotected] is created in MySQL server. NSCA stands for Nagios Service Check Acceptor. If up-to-date information has been provided by a passive check during this period, then it will not perform active checks. By using this website, you agree with our Cookies Policy. . (1)Nagios. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Monthly digest of what's new and exciting from us. Some methods support checking multiple services at once. Nagios's primary mode of "service checking" is called an active check. http://www.waggy.at/nagios/capture_plugin.htm, 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). 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. See Also: Active Checks, Host Checks, Check Scheduling, Predictive Dependency Checks. To identify the status of a monitored service, Nagios runs a check plugin on it. This is because, very often, passive checks are used to report host and service statuses from other Nagios instances. . 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. 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. These types of checks are called Active Checks. In such cases, only reports regarding hard state changes are propagated across Nagios servers. Next, update the remote Docker daemon DNS details on your hosts file if there is no local DNS; sudo tee -a "192.168.59.48 docker01.kifarunix.com docker01" >> /etc/hosts. Monitoring Website URL Status Repeat this procedure for each Ceph plug-in applicable to the node. >Mainly Focus on Kafka and Cloudera services, Cluster . Nagios can monitor DNS service by asking the DNS server to either resolve a specific fully qualified domain name (FQDN), or by asking the server to use the dig tool. Agree Enter file in which to save the key (/home/nagios/.ssh/id_dsa): Enter passphrase (empty for. Nagios can check whether the server is online by running ping on the IP/name of the server as well as it can be set up to provide warnings in case the round trip time (RTT) to the server increases. Do roots of these polynomials approach the negative of the Euler-Mascheroni constant? Enjoy unlimited access on 5500+ Hand Picked Quality Video Courses. http://exchange.nagios.org/directory/Plugins, linux.about.com/library/cmd/blcmdl1_watch.htm, How Intuit democratizes AI development across teams through reusability. It has been designed to run . 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. Check whether Apache HTTP is running on a remote server using check_http. In fact, we officially. Checking if a service is running using SNMP is not very straight forward, checking a process is the best solution here, please refer to the Process Checks KB article. will hold the return value of commands between $( ). Here is how it can be done. 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. These checks help ensure that the dependency logic is as accurate as possible. debug_level=2048 With nagios in debug mode I simply tail the debug_log file debug_file=/var/log/nagios3/nagios.debug. Each of these options opens the Manage Service Template screen.The New option will have no pre-selected directive values, Copy lets you create a new template based on an existing templates properties, and Modify enables the editing of an . The best answers are voted up and rise to the top, Not the answer you're looking for? Note: Passive host checks are normally treated as HARD states, unless the passive_host_checks_are_soft option is enabled. Note: A host must be defined in Nagios before you can submit passive check results for it! 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. 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. The host status code should be 0 for an UP state, 1 for DOWN and 2 for an UNREACHABLE state. Examples: CPU load, RAID status An snmp system is generally considered to have 3 components: Agents Agents expose management information on a device. 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. You know the basics on Nagios administration. Based on whether the read was successful or not, the appropriate status code, along with plugin output, is sent out. Now let us add check_interval directive. A sample definition for a host that runs an active check if there has been no result provided within the last two hours: The following is an illustration showing when Nagios would invoke active checks: Each time there is at least one passive check result that is still valid (i.e., was received within the past two hours), Nagios will not perform any active checks. Service - Started Check to see if a service is started. It looks like that with the default install, theres no configuration set up to tell Icinga where to look for the check_http executable. NPCA allows you to check multiple services, here is an example that checks for some services that are running and some that are stopped. 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. Current status from nagios Web interface: Thank you article really help a beginer like me ;-). This allows for seamless integration of status information from external applications with Nagios. While Nagios can monitor multiple OSes, the server must reside on a Linux or Unix variant such as FreeBSD or Solaris. Nagios Plugins does not include a service plugin however the linux-nrpe-agent does provide check_init_service. Nagios dependencies.cfg example file. Copyright (c) 1999-2014 Nagios Plugin Development Team <devel@nagios-plugins.org> This plugin tests the HTTP service on the specified host. does the HTML display xx welcome xx? No paper. External applications can submit passive service check results to Nagios by writing a PROCESS_SERVICE_CHECK_RESULT external command to the external command file. The command to submit passive checks is PROCESS_HOST_CHECK_RESULT (visit http://www.nagios.org/developerinfo/externalcommands/commandinfo.php?command_id=115). Is it possible to check a web page through an authenticated proxy server? Otherwise we must rely on parsing the # output from the service management tool. Unlike with active host checks, Nagios does not (by default) attempt to determine whether or host is DOWN or UNREACHABLE with passive checks. NSClient++ includes a service module that can check if a service is running. The script should then post results to the Nagios daemon. 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. This mechanism includes password protection, along with encryption, to prevent injection of false results in to Nagios. Another example is where an application already processes information such as network bandwidth utilization. You can create a host file inside the server directory of Nagios and mention the host and service definitions. ##### # # NAGIOS.CFG - Sample Main Config File for Nagios # # Read the documentation for more information on this configuration # file. So in the server set the files: /usr/local/nagios/etc/objects/commands.cfg: /usr/local/nagios/etc/objects/nrpeclient.cfg: Note that the ! Hi, this is a fantastic article, i managed to learn how to make plugins myself. In the following example, we are checking whether the website certificate expires in the next 365 days. An external application checks the status of a host or service. By default, Nagios handles results from active and passive checks differently. Save my name, email, and website in this browser for the next time I comment. The figure shown below shows a passive check . Active checks are most common in the Nagios world. Hosts and service configurations are the building blocks of Nagios Core. This means that if Nagios receives a result indicating that a host is DOWN, it assumes that all child hosts are in an UNREACHABLE state. # Nagios Exit Codes OK=0 WARNING=1 CRITICAL=2 UNKNOWN=3 # Weather or not we can trust the exit code from the service management tool. If youve installed Nagios from source, check_httpd command will be located in the /usr/local/nagios/libexec directory. The documentation uses the example of: for . Just cd (or not) into the plugins directory (this directory location varies, depending on how you've installed it, but check /usr/local/nagios, or /usr/lib/nagios). Kaydolmak ve ilere teklif vermek cretsizdir. When you restart the Nagios, this host will start getting monitored by Nagios and the specified services will run. Go to the Nagios interface via a web browser and log in as the nagiosadmin user. Add the command to the NRPE configuration file on the client (/etc/nagios/nrpe_local.cfg): Now we can access the server and test it like any standard plugin. Unlike active checks, Nagios will not take network topology into consideration by default. It can report each problem when accessing the database. 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. They may or may not work on: 44 # your system, as they must be modified for your plugins. Using the definition below, checks on the host will be performed after every 3 minutes. @sunardo I just ran into this exact same thing. Nagios check_udp_ports returning critical: result to scheduled check, runs fine manually, Nagios - check procs and --metric=elapsed on the same service. To monitor hosts and services running on remote machines, Nagios executes plugins and tells what information to collect. 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. Method 3. How can I get it to work with https with Nagios4 and plugins 2.x? 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. After installing nagios and nagios-plugins-all (via yum), I've c. hello.. # Defaults to 0, put to 1 for systemd. 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. just because i had already looked in the commands.cfg file to figure out which commands were running, but i wanted to know what flags were being set. This defines that check_nrpe is the command and check_root_home_du is the value of $ARG1$. Nagios can monitor different mail server components like SMTP, POP, IMAP and mailq. Always remember, prior to reloading Nagios, check that there are no errors in the configuration. if one of my checked systems goes down, and therefore fails a PING check, I do NOT need to be notified that a file system is unavailable, or that SSH is down, too. 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. Passive checks are performed by external processes and the results are given back to Nagios for processing. 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. For example, when a web application cannot connect to the database, it will let Nagios know about it immediately. In Nagios, 2 types of checks are performed on hosts and services . ##### ##### # # SAMPLE SERVICE CHECK COMMANDS # # These are some example . Check WMI Plus includes a service module that can check if a service is stopped. Allow Nagios server to run commands on the client by adding it to the allowed_hosts entry in /etc/nagios/nrpe.cfg. To use a custom script as a plugin to run remotely through NRPE, you should first write the script on the server, for instance in /usr/local/scripts/check_root_home_du.sh: The previous script is a very simple example, checking the disk usage of the directory /root and setting a threshold for considering it OK, Warning or Critical. Nagios will ignore all check results for hosts that had not been configured before it was last (re)started. Did any DOS compatibility layers exist for any UNIX-like systems before DOS started to become outmoded? sudo usermod -aG docker kifarunix. For example, if you are bringing down your HTTP server everyday sometime between midnight and 1:59 a.m, you can specify the above "247-except-night-12-2" timeperiod in your service definition for the check_period and notification_period as shown below for your particular service definition. Note that there are possible security implications of this change, so it's worth mentioning a few words: The following tuning should do the trick. Previous parts of this book often mentioned Nagios performing checks on various software and machines. See the HTML : 45 The figure shown below shows an active check . 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. # SAMPLE HOST CHECK . Nagios is the most popular tool which is used to monitor hosts and services running in your IT infrastructure. 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. I wouldn't leave this setting on normally though, it is very verbose and fills your log file at a rapid rate. With a little tweaking, Nagios can help monitor this application port as well. When a host is reported to be DOWN as a passive check result, Nagios does not perform a translation from DOWN to UNREACHABLE. When a host or service is down for a very short duration of time and its status is not known or different from previous one, then soft states are used. Last updated on September 22, 2020 by Sarmed Rahman. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Force a check and you will see exactly how the command is being run. When max_check_attempts is executed and status of the host or service is still not OK, then hard state is used. Rather, Nagios takes the passive check result to be the actual state the host is in and doesn't try to determine the host's actual state using the reachability logic. 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. First as pending: To run a script on a remote client, you will need to set up the Nagios Remote Plugin Executor (NRPE). It is called NSCA (Nagios Service Check Acceptor). 5 check_http Command Examples 1. check_command /usr/share/nagios/plugins/check_http -H MYIP -u http://MYIP/test.php, Hi, Up To: Contents These are real-time graphs showing things like CPU usage, memory usage, and bandwidth. Hello, ask a question, check_http detect page size, page size detection value changes again, the alarm. For example: These are examples of the graphs that can be created and embedded using the graph generator in the Graphs tab. I've: 5 # provided some comments here, but things may not be so clear without further . They have a lot of advantages and some disadvantages. When it comes to checking MySQL, it should be kept in mind that MySQL, by default, listens on only the loopback interface 127.0.0.1.