Styling Nagios output for a large display

Udgivet den december 1, 2023 af mike

Theres not really any built in features for styling Nagios, so i devised a simple workaround that utilizes html, css and jquery to do the trick.

We need to run this on the same domain as Nagios itself or disable cors for this to work.

<html>        
 <head>
  <title>Nagios Services Monitor</title>
  <script 
    src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js">
  </script>
  <style>
   body {
    padding: 0;
    margin: 0;
   }
   #nagios {
    height: 100%;
    width: 100%;
    overflow: hidden;
    zoom: 175%;
   }  
  </style>
 </head>
 <body>
  <div id=nagios></div>
  <script>
   $(document).ready(function(){                               
   setInterval(function()                                
   {
    $.get('/cgi-bin/nagios4/status.cgi?host=all&servicestatustypes=28',
     function(data) {    
      data = data.replace("Updated every 90 seconds",
                          "Updated every second");
      data = data.replaceAll(/<script[\s\S]+<\/script>/g,
                            "<!-- scripts removed -->");
      $('#nagios').html(data);
                       });
      },1000);
   });
   </script>
 </body>
</html>

Tested in Chromium.

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Delete USB partitions on Windows

Udgivet den december 1, 2023 af mike

Really useful if you have a USB Stick which have been used for installing Debian or another Linux and you wish to use it for something on Windows, the graphical partition manager in Windows are way to retarded to do this, but luckily there’s a CLI tool who can do it:

C:\Users\mike> diskpart

Now windows will show a popup asking for permissions to run this tool with administrator privileges, after you granted this you will be in a “DISKPART” prompt, now do this:

Microsoft DiskPart version 10.0.19041.3636

Copyright (C) Microsoft Corporation.
On computer: OFFICEPC

DISKPART> list disk

  Disk ###  Status         Size     Free     Dyn  Gpt
  --------  -------------  -------  -------  ---  ---
  Disk 0    Online          111 GB  1024 KB
  Disk 1    Online           28 GB  1024 KB

DISKPART> select disk 1

Disk 1 is now the selected disk.

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    Primary              1 GB  1024 KB
  Partition 2    Primary             27 GB     1 KB

DISKPART> select partition 1

Partition 1 is now the selected partition.

DISKPART> delete partition

DiskPart successfully deleted the selected partition.

DISKPART> exit

You obviously need to repeat this for all the partitions you need to delete.

More info: https://learn.microsoft.com/en-us/windows-server/administration/windows-commands/diskpart

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Automating USBIP server

Udgivet den november 28, 2023 af mike

In a prior post we installed USBIP and used it manually, in this post I will set it up “the correct Debian(systemd) way”.

But first, for completeness sake, we will go through installation progress again, first install the package:

root@host:~# apt-get install usbip

Load the main module and make it persistent:

root@server:~# modprobe usbip_core
root@server:~# modprobe usbip_host
root@server:~# echo usbip_core >> /etc/modules
root@server:~# echo usbip_host >> /etc/modules

Create service-file for usbip-deamon, create /etc/systemd/system/usbipd.service with following content:

[Unit]
Description=Usbipd
After=network.target

[Service]
Type=forking
ExecStart=/usr/sbin/usbipd -D

[Install]
WantedBy=multi-user.target

Enable and start it:

root@server:~# systemctl enable usbipd --now
Created symlink /etc/systemd/system/multi-user.target.wants/usbipd.service → /etc/systemd/system/usbipd.service.

Then we need a systemd service file for sharing usb-devices, create /etc/systemd/system/usbip-device@.service containing the following:

[Unit]
Description=USBIP Device %I
Requires=usbipd.service
After=usbipd.service

[Service]
RemainAfterExit=yes
ExecStart=/usr/sbin/usbip bind --busid=%i
ExecStop=/usr/sbin/usbip unbind --busid=%i

[Install]
WantedBy=multi-user.target

And Finally start and enable this pseudo-service:

root@server:/etc/systemd/system# systemctl enable usbip-device@3-3 --now
Created symlink /etc/systemd/system/multi-user.target.wants/usbip-device@3-3.service → /etc/systemd/system/usbip-device@.service.

Try to reboot and verify from the client:

root@backup2:~# usbip list -r backup1
Exportable USB devices
======================
 - backup1
        3-3: Sony Corp. : unknown product (054c:05b9)
           : /sys/devices/pci0000:00/0000:00:10.0/usb3/3-3
           : (Defined at Interface level) (00/00/00)
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USBIP on Debian 12 – USB Device Sharing over IP network

Udgivet den november 28, 2023 af mike

In a world were virtualization is slowly creeping in everywhere the demand for virtual USB cables are growing, luckily the USBIP protocol are implemented in the Linux kernel – and the userland tools are partly implemented in Debian, at least enough for us to mount it manually. If you want to automate it I made another post for that.

On both client and server:

Install the package:

root@system:~# apt-get install usbip

Load the main module and make it persistent:

root@system:~# modprobe usbip_core
root@system:~# echo usbip_core >> /etc/modules

Setting up the server:

The server needs an aditional kernel module:

root@server:~# modprobe usbip_host
root@server:~# echo usbip_host >> /etc/modules

Now you can share the usb device, I plugged in a USB stick into my server:

root@server:~# usbip list -l
 - busid 3-3 (054c:05b9)
   Sony Corp. : unknown product (054c:05b9)

This server only have one usb device attached making the output pretty simple, in this case the busid is “3-3”, but on your system it may have a different format depending on your hardware.

Bind this device to usbip:

root@server:~# usbip bind --busid=3-3
usbip: info: bind device on busid 3-3: complete

And finally start the deamon:

root@server:~# usbipd
usbipd: info: starting usbipd (usbip-utils 2.0)
usbipd: info: listening on 0.0.0.0:3240
usbipd: info: listening on :::3240

This is still a very manual process, later I will create an additional post with an example on how to automate this on Debian 12.

Setting up the client

The client also need a module:

root@client:~# modprobe vhci-hcd
root@client:~# echo vhci-hcd >> /etc/modules

And now you can connect to the remote server and list available devices:

root@client:~# usbip list -r server
Exportable USB devices
======================
 - backup1
        3-3: Sony Corp. : unknown product (054c:05b9)
           : /sys/devices/pci0000:00/0000:00:10.0/usb3/3-3
           : (Defined at Interface level) (00/00/00)

… and attach it:

root@client:~# usbip attach -r server -b 3-3

Which will cause it pop up in dmesg:

root@client:~# dmesg | tail -n10
[3425534.758312] usb-storage 5-1:1.0: USB Mass Storage device detected
[3425534.758672] scsi host9: usb-storage 5-1:1.0
[3425535.790312] scsi 9:0:0:0: Direct-Access     Sony     Storage Media    PMAP PQ: 0 ANSI: 6
[3425535.790979] sd 9:0:0:0: Attached scsi generic sg5 type 0
[3425535.792699] sd 9:0:0:0: [sde] 30375936 512-byte logical blocks: (15.6 GB/14.5 GiB)
[3425535.793509] sd 9:0:0:0: [sde] Write Protect is off
[3425535.793521] sd 9:0:0:0: [sde] Mode Sense: 45 00 00 00
[3425535.794265] sd 9:0:0:0: [sde] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
[3425535.801659]  sde:
[3425535.801757] sd 9:0:0:0: [sde] Attached SCSI removable disk

Now you can mount the device:

root@client:~# mount /dev/sde /mnt
mount: /mnt: WARNING: source write-protected, mounted read-only.
root@backup2:~# ls /mnt
boot  client_install  EFI  EULA  install.img  LICENSES  Packages  repodata  RPM-GPG-KEY-CH-8  RPM-GPG-KEY-CH-8-LCM  RPM-GPG-KEY-Platform-V1

And now your Debian Install USB stick from “server” is mounted on “client”, I have not yet done any kind of methodical testing so I don’t really know how the performance is, but right now I was more concerned with getting it to work, than what kind of performance it would deliver, it is probably “good enough” for anything except for maybe high latency gaming and huge data transfers.

But I still made a quick benchmark using:

root@system:~# hdparm -t /dev/sde

On both systems where i got around 200MB/sec on the local system and 85MB/sec on the remote client. But my current use-case is to connect printers and scanners, and the occasional USB Stick to transfer small amounts of files.

For any kind of serious ingestion of video materials I would not recommend this solution.

Detaching USB Device

root@client:~# umount /mnt
root@client:~# usbip port
Imported USB devices
====================
Port 15: <Port in Use> at Super Speed(5000Mbps)
       Sony Corp. : unknown product (054c:05b9)
       5-1 -> usbip://backup1:3240/3-3
           -> remote bus/dev 003/002
root@client:~# usbip detach -p 15
usbip: info: Port 15 is now detached!

Next task is to automate this.

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Logging output of cronjobs

Udgivet den oktober 25, 2023 af mike

If you wish to send output of cronjobs to syslog instead of email use the following:

20 10 * * * /opt/script/dostuff.py 2>&1 | /usr/bin/logger -t stuffdoer

If you want live-updates in the log file it can be necessary to unbuffer it, install the “expect” package and modify the command like so:

20 10 * * * /usr/bin/unbuffer /opt/script/dostuff.py 2>&1 | /usr/bin/logger -t stuffdoer

If it’s a python script you can accomplish the same thing by adding “-u” to the shebang.

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PHP Script to parse nagios.dat

Udgivet den september 5, 2023 af mike

Please add your own error-handling:

#!/usr/bin/php
<?php

function NagiosParser($file)
{
        $status = file_get_contents($file);

        $current = null;
        $parsed = array();

        foreach (explode("\n", $status) as $line)
        {
                if (preg_match('/^([a-z]+) {$/', $line, $matches))              // Block start
                {
                        $block = array();
                        $current = $matches[1];
                }
                else if (preg_match('/}$/', $line, $matches))                   // Block stop
                {
                        $parsed[$current][] = $block;
                        $current = null;
                        unset($block);
                }
                else if (preg_match('/([a-z_]+)=(.+)/', $line, $matches))       // Not null value
                        if ($current == null)
                                die("Parse error: Value outside of block!");
                        else
                                $block[$matches[1]] = $matches[2];
        }
        return $parsed;
}
print_r(NagiosParser("status.dat"));
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Nagios module for monitoring smsdlog for modem-connectivity

Udgivet den marts 31, 2023 af mike 
#!/usr/bin/php
<?php

function secondsToTime($inputSeconds)
{
        $secondsInAMinute = 60;
        $secondsInAnHour  = 60 * $secondsInAMinute;
        $secondsInADay    = 24 * $secondsInAnHour;

        // extract days
        $days = floor($inputSeconds / $secondsInADay);

        // extract hours
        $hourSeconds = $inputSeconds % $secondsInADay;
        $hours = floor($hourSeconds / $secondsInAnHour);

        // extract minutes
        $minuteSeconds = $hourSeconds % $secondsInAnHour;
        $minutes = floor($minuteSeconds / $secondsInAMinute);

        // extract the remaining seconds
        $remainingSeconds = $minuteSeconds % $secondsInAMinute;
        $seconds = ceil($remainingSeconds);

        $res = array();

        if ($days > 0)
                $ret[] = "$days days";

        if ($hours > 0)
                $ret[] = "$hours hours";

        if ($minutes > 0)
                $ret[] = "$minutes minutes";

        if ($seconds > 0)
                $ret[] = "$seconds seconds";

        // return the final array
        $obj = array(
                'd' => (int) $days,
                'h' => (int) $hours,
                'm' => (int) $minutes,
                's' => (int) $seconds,
        );
        if (empty($ret))
                return "0 seconds";
        else
                return implode(", ",$ret);
}

date_default_timezone_set('UTC');
$cmd = exec("grep 'Signal Strength' /var/log/smstools/smsd.log | /usr/bin/tail -n 1");
if (!$cmd)
{
        print("CRITICAL: No lifesign from modem in current logfile\n");
        die(2);
}

list ($year, $month, $day, $hour, $min, $sec) = preg_split("/:|-| /", explode(",", $cmd)[0] );
$ts = mktime($hour, $min, $sec, $month, $day, $year);
$diff = time() - $ts;

if ($diff < 30)
{
        print ("OK: Last lifesign from modem ".secondsToTime($diff)." ago\n");
        die(0);
}
else
{
        print ("CRITICAL: Last lifesign from modem ".secondsToTime($diff)." ago\n");
        die(2);
}
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Function to parse contacts from nagios config

Udgivet den marts 30, 2023 af mike 
#!/usr/bin/php
<?php
$contacts = file_get_contents("/etc/nagios4/objects/auto-contacts.cfg");


function parse_contacts($cfg)
{
        preg_match_all("/define contact{(.*?)}/mis", file_get_contents($cfg), $matches);
        foreach ($matches[1] as $match)
        {
                preg_match_all("/\s+(.+?)\s+(.+?)\n/mis", $match, $m);
                for ($i=0; $i&lt;count($m[1]); $i++)
                        $contact[$m[1][$i]] = $m[2][$i];
                $contacts[] = $contact;
        }
        return $contacts;
}


print_r(parse_contacts("/etc/nagios4/objects/contacts.cfg"));
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Tunneling HP ILO5 through SSH

Udgivet den oktober 27, 2022 af mike

Creates a tunnel to the ilo port, which in this example is 10.0.0.201 through the jumphost, after this you can connect to ILO by typing in https://locahost and accept the security warning, refreshing and logging in with your credentials.

 ssh jumphost.yourcompany.com -l root -L 443:10.0.0.201:443 -L 17990:10.0.0.201:17990 -L 80:10.0.0.201:80
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Unmounting an NFS Share that has gone away

Udgivet den oktober 24, 2022 af mike

On Linux when an NFS share disappears it is not handled very well, to say it nicely, and in order to get a functioning machine again you need to drop that mount, but a simple umount command states that the device is busy.

So you need to both use the lazy and the force flag:

# umount -l -f /mnt/nfsshare
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