{"id":3250,"date":"2024-04-21T18:18:00","date_gmt":"2024-04-21T12:48:00","guid":{"rendered":"https:\/\/www.veeble.org\/kb\/?p=3250"},"modified":"2025-03-19T10:29:05","modified_gmt":"2025-03-19T04:59:05","slug":"how-to-monitor-nagios-alerts","status":"publish","type":"post","link":"https:\/\/www.veeble.com\/kb\/how-to-monitor-nagios-alerts\/","title":{"rendered":"How To Monitor Nagios Alerts"},"content":{"rendered":"\n<figure class=\"wp-block-image aligncenter size-full is-resized\"><a href=\"https:\/\/www.veeble.org\/kb\/wp-content\/uploads\/2024\/04\/Screenshot-2024-04-30-090858.png\" target=\"_blank\" rel=\"noopener\"><img loading=\"lazy\" decoding=\"async\" width=\"1012\" height=\"536\" src=\"https:\/\/www.veeble.org\/kb\/wp-content\/uploads\/2024\/04\/Screenshot-2024-04-30-090858.png\" alt=\"nagios alert\n\" class=\"wp-image-3273\" style=\"width:763px;height:auto\" srcset=\"https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/Screenshot-2024-04-30-090858.png 1012w, https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/Screenshot-2024-04-30-090858-300x159.png 300w, https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/Screenshot-2024-04-30-090858-768x407.png 768w\" sizes=\"auto, (max-width: 1012px) 100vw, 1012px\" \/><\/a><\/figure>\n\n\n\n<p><a href=\"https:\/\/www.nagios.org\/\" target=\"_blank\" rel=\"noopener\">Nagios<\/a> is like a watchful guardian for systems. It keeps an eye on everything from servers to networks and applications, making sure they&#8217;re working properly. If something goes wrong, like a server running out of space or an excessive number of processes. Nagios sends out alerts to let us know so they can fix the problem quickly. It&#8217;s like having a reliable alarm system for the digital world!&nbsp;<\/p>\n\n\n\n<p>Always consider implementing resource monitoring and alerting mechanisms (using tools like Prometheus, Nagios, or Zabbix) to keep track of your server and to take proactive actions.<\/p>\n\n\n\n<p>Once the nagios alert is received,&nbsp; we can manually check and resolve each of the Nagios alerts by using commands like top, htop, wc -l, and others:<\/p>\n\n\n\n<p>Now we can discuss about different Alerts.&nbsp;<\/p>\n\n\n<div role=\"navigation\" aria-label=\"Table of Contents\" class=\"simpletoc wp-block-simpletoc-toc\"><h2 style=\"margin: 0;\"><button type=\"button\" aria-expanded=\"false\" aria-controls=\"simpletoc-content-container\" class=\"simpletoc-collapsible\">Table of Contents<span class=\"simpletoc-icon\" aria-hidden=\"true\"><\/span><\/button><\/h2><div id=\"simpletoc-content-container\" class=\"simpletoc-content\"><style>html { scroll-behavior: smooth; }<\/style><ul class=\"simpletoc-list\">\n<li><a href=\"#disk-monitoring\">Disk monitoring<\/a>\n\n<\/li>\n<li><a href=\"#current-user-warning\">Current user warning<\/a>\n\n<\/li>\n<li><a href=\"#cpu-load-warning\">CPU Load Warning<\/a>\n\n<\/li>\n<li><a href=\"#total-process-criticalnbsp\">Total process critical&nbsp;<\/a>\n\n<\/li>\n<li><a href=\"#mail-monitoring\">Mail monitoring<\/a>\n<\/li><\/ul><\/div><\/div>\n\n<h2 class=\"wp-block-heading\" id=\"disk-monitoring\">Disk monitoring<\/h2>\n\n\n<p>To check disk space in Linux, you can use the df -hT command, which displays information about filesystems in a human-readable format. Here&#8217;s how you can use it:<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>Open a terminal on your Linux system.<\/li>\n\n\n\n<li>Type the following command and press Enter:<\/li>\n<\/ol>\n\n\n\n<pre class=\"wp-block-code\"><code>df -hT<\/code><\/pre>\n\n\n\n<p>This command will show you a list of filesystems along with their disk space usage in a human-readable format, including the filesystem type (Type), total size (Size), used space (Used), available space (Avail), percentage used (Use%), and mount point (Mounted on).<\/p>\n\n\n\n<p><strong>Identify Large Files and Directories:<\/strong><\/p>\n\n\n\n<p>Use commands like du -sh * in different directories to identify large files and directories consuming significant disk space. Once identified, you can decide whether to delete or archive them.<\/p>\n\n\n\n<p><strong>Clean Temporary Files:<\/strong><\/p>\n\n\n\n<p>Remove unnecessary temporary files using commands like sudo rm -rf \/tmp\/* or sudo apt clean (for Debian-based systems) to free up space.<\/p>\n\n\n\n<p><strong>Clear Package Cache:<\/strong><\/p>\n\n\n\n<p>If you&#8217;re using a package manager like apt, you can clear the package cache using sudo apt clean to free up space used by downloaded package files.<\/p>\n\n\n<h2 class=\"wp-block-heading\" id=\"current-user-warning\">Current user warning<\/h2>\n\n\n<p>To Check who is currently logged into the server, use&nbsp; who command<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Who<\/code><\/pre>\n\n\n\n<p>List all users on the system from the \/etc\/passwd file:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>cat \/etc\/passwd<\/code><\/pre>\n\n\n<h2 class=\"wp-block-heading\" id=\"cpu-load-warning\">CPU Load Warning<\/h2>\n\n\n<p>To check CPU load and monitor for warnings in Linux, you can use the top command or htop for a more interactive display.&nbsp;<\/p>\n\n\n\n<p>Open a terminal and run either of the following commands:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Top&nbsp;<\/code><\/pre>\n\n\n\n<p>Or&nbsp;<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Htop<\/code><\/pre>\n\n\n\n<p>These commands will show you a list of processes along with CPU usage information, load averages, and more.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Identify High CPU Usage:<\/li>\n<\/ul>\n\n\n\n<p>Look for processes that are consuming a high percentage of CPU resources. In the top or htop output, the %CPU column shows the CPU usage of each process.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Check Load Average:<\/li>\n<\/ul>\n\n\n\n<p>In the top output, you&#8217;ll see load average values at the top of the screen. Load average values represent system load over 1, 5, and 15-minute intervals. High load averages indicate heavy CPU usage.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Investigate Specific Processes:<\/li>\n<\/ul>\n\n\n\n<p>If you identify processes with high CPU usage, investigate why they are consuming resources. Use tools like ps aux or pidstat -p &lt;PID&gt; to gather more information about specific processes.<\/p>\n\n\n<h2 class=\"wp-block-heading\" id=\"total-process-criticalnbsp\">Total process critical <\/h2>\n\n\n<ol class=\"wp-block-list\">\n<li>Use the top command to check the current system processes and their resource usage.<\/li>\n\n\n\n<li>Look for any processes that are consuming a disproportionately high amount of CPU, memory, or other resources.<\/li>\n\n\n\n<li>Note down the PID (Process ID) of the process causing the issue.<\/li>\n\n\n\n<li>Use the ps aux | grep &lt;PID&gt; command to gather more information about the process, including its command-line arguments and resource consumption.<\/li>\n\n\n\n<li>If the process is non-essential, consider terminating it using the kill command with the appropriate signal.\n<ul class=\"wp-block-list\">\n<li>Example: sudo kill -9 &lt;PID&gt; (replace &lt;PID&gt; with the actual Process ID).<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n\n\n<h2 class=\"wp-block-heading\" id=\"mail-monitoring\">Mail monitoring<\/h2>\n\n\n<p>We have already discussed about mail monitoring alert in a <a href=\"https:\/\/www.veeble.org\/kb\/managing-exim-mail-server-in-linux\/ .\" target=\"_blank\" rel=\"noopener\">previous article&nbsp;<\/a><\/p>\n\n\n\n<div style=\"height:25px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<div class=\"wp-block-uagb-call-to-action uagb-block-81532755 wp-block-button\"><div class=\"uagb-cta__wrap\"><h3 class=\"uagb-cta__title\">Reliable VPS Hosting<\/h3><p class=\"uagb-cta__desc\">Dependable Managed VPS solutions for your growing business. Fast setup, expert support.<\/p><\/div><div class=\"uagb-cta__buttons\"><a href=\"https:\/\/www.veeble.com\/in\/managed-vps\/\" class=\"uagb-cta__button-link-wrapper wp-block-button__link\" target=\"_blank\" rel=\"noopener noreferrer\">Choose Your VPS<svg xmlns=\"https:\/\/www.w3.org\/2000\/svg\" viewBox=\"0 0 512 512\"><path d=\"M504.3 273.6l-112.1 104c-6.992 6.484-17.18 8.218-25.94 4.406c-8.758-3.812-14.42-12.45-14.42-21.1L351.9 288H32C14.33 288 .0002 273.7 .0002 255.1S14.33 224 32 224h319.9l0-72c0-9.547 5.66-18.19 14.42-22c8.754-3.809 18.95-2.075 25.94 4.41l112.1 104C514.6 247.9 514.6 264.1 504.3 273.6z\"><\/path><\/svg><\/a><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Nagios is like a watchful guardian for systems. It keeps an eye on everything from servers to networks and applications, making sure they&#8217;re working [&hellip;]<\/p>\n","protected":false},"author":9,"featured_media":7585,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[5],"tags":[],"class_list":["post-3250","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-linux"],"uagb_featured_image_src":{"full":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts.jpg",1366,768,false],"thumbnail":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts-150x150.jpg",150,150,true],"medium":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts-300x169.jpg",300,169,true],"medium_large":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts-768x432.jpg",768,432,true],"large":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts-1024x576.jpg",1024,576,true],"1536x1536":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts.jpg",1366,768,false],"2048x2048":["https:\/\/www.veeble.com\/kb\/wp-content\/uploads\/2024\/04\/How-To-Monitor-Nagios-Alerts.jpg",1366,768,false]},"uagb_author_info":{"display_name":"Nayana Nair","author_link":"https:\/\/www.veeble.com\/kb\/author\/nayana\/"},"uagb_comment_info":0,"uagb_excerpt":"Nagios is like a watchful guardian for systems. It keeps an eye on everything from servers to networks and applications, making sure they&#8217;re working [&hellip;]","_links":{"self":[{"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/posts\/3250","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/users\/9"}],"replies":[{"embeddable":true,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/comments?post=3250"}],"version-history":[{"count":7,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/posts\/3250\/revisions"}],"predecessor-version":[{"id":8188,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/posts\/3250\/revisions\/8188"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/media\/7585"}],"wp:attachment":[{"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/media?parent=3250"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/categories?post=3250"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.veeble.com\/kb\/wp-json\/wp\/v2\/tags?post=3250"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}