June 2024 - Xymon - Xymon mailman web

Devmon on RHEL9
by colin.coe＠gmail.com 13 Dec '24

13 Dec '24

Hi all Has anyone got DEVMON working on RHEL9? I'm working with https://github.com/bonomani/devmon but can't get any SNMP polling working. The current server is RHEL6 and working (mostly) fine but I need to get off RHEL6/7. Thanks

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unset 'testip' per-host after using in .default.
by john.thurston＠alaska.gov 28 Jun '24

28 Jun '24

The 'testip' tag tells xymonnet to "use the IP listed in the hosts.cfg file", rather than performing a lookup in DNS of the hostname. It can be included in a .default. line. But once it is in that .default. line, I can not find a way to disable 'testip' for a single host. Is there a way to do this? -- -- Do things because you should, not just because you can. John Thurston 907-465-8591 John.Thurston at alaska.gov Department of Administration State of Alaska

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[xymon]repair rrd data
by diffusion＠bulot-fr.com 22 Jun '24

22 Jun '24

Hello I have many ncv graph and they often "dotted" instead made of lines It's like some data left in rrd : see attachment * How to correct without loosing all data ? * how it's happened ? I had search for "rrd repair tools" but nothing seems works on my server or PEBCAK ;-) (hope my english is not too bad)

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xymon checking wrong SSL cert on CNAME
by betsys＠well.com 15 Jun '24

15 Jun '24

Hi, We have a website at a third-party hosting company, where our site https://www.example.com <http://www.example.com> is a cname for something.hosting.com (not the real name) We have a LetsEncrypt cert issued for www.example.com <http://www.example.com> . The cert wasn't updating, but xymon did not alert , because xymon is apparently evaluating the CNAME and then checking the cert for hosting.com (which has a wildcard cert *.hosting.com) How do we make xymon check the cert for www.example.com <http://www.example.com> , other than writing our own script? I think this is a fairly common setup for hosted websites (for a minute I thought about adding an A record but that would be wrong on multiple levels) /home/xymon/server/etc/hosts.cfg has x.x.x.x www.example.com # noconn httpstatus;http://www.example.com/;301; https://www.example.com (where x.x.x.x is the actual IP) Running xymon 4.3.30 on Alma 8 Thanks very much!

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Whoops ! Failed to load current Xymon status, (Cannot resolve hostname)
by jerryshenk＠gmail.com 11 Jun '24

11 Jun '24

I'm installing a new Xymon system on Ubunto 24 LTS. Things seem like they are running but, the only host any "dots" is the xymon host itself. When I add other hosts to the hosts.cfg file, they show up but only have a dash instead of the green, yellow, or red dot. If I tail /var/log/xymon/xymongen.log, I get the following error repeatedly. 2024-06-11 14:10:42.740606 Whoops ! Failed to send message (Cannot resolve hostname) 2024-06-11 14:10:42.740701 -> Cannot determine IP address of message recipient 127.0.0.1, 2024-06-11 14:10:42.740708 -> Recipient '127.0.0.1, 10.118.15.13', timeout 15 2024-06-11 14:10:42.740713 -> 1st line: 'xymondboard fields=hostname,testname,color,flags,lastchange,logtime,validtiacktime,disabletime,sender,cookie,line1,acklist ' 2024-06-11 14:10:42.740735 xymond status-board not available, code 2 2024-06-11 14:10:42.740740 Failed to load current Xymon status, aborting page-update I'm not sure how relevant this is but, I've used bb to connect to both local host (127.0.0.1) and the actual IP address and if I pass hostinfo option, I get a list of hosts the same as the web site shows. If I pass the option config (/usr/lib/xymon/server/bb 127.0.0.1 'config') there is a 15 second delay and then a "Whoops ! Failed to send message (timeout)" error. ReplyForward Add reaction

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Cross compilation
by jeremy＠laidman.org 04 Jun '24

04 Jun '24

Grant Sorry, I'm not a developer, so I can't help you with cross-compiling. Best of luck with that! You may have already solved this issue, but if you're doing client->server comms to send client messages, you would typically need the "xymon" binary to run on the client host, for sending the client message to the Xymon server. There are alternative ways to do this, such as using netcat (example below), or a short perl script, or even telnet (see the Xymon Tips <https://xymon.sourceforge.io/xymon/help/xymon-tips.html#noinstall> page for more on this). As far as I can tell, the date and time in the client message is only used in the CPU test to report when the system clock is significantly different from that on the Xymon server. If this is not important to you (eg if you have an alternative check for this) then you can do without the date and time. But if you need message monitoring, you can't easily do without the thing that gives the time and date anyway, so this isn't all that helpful to you. To elaborate on the capturing of Xymon client output for central mode, the client can run in either local mode (if run with "--local" as the first parameter) or central mode (the default). In client mode, it gets its configuration from the localclient.cfg file stored on the client. In central mode, it gets its configuration from the server, as a post-script to the transmission of the client data. In central mode, when xymonclient.sh sends a "client" type message to the Xymon server, the server fetches any relevant sections from its own clientlocal.cfg file that are appropriate for the client (ie matching the OS type, class, and hostname). For example, if I have a Linux Xymon client machine called x-client.example.com, and in clientlocal.cfg (on the Xymon server) I have: [linux] log:/var/log/messages:10240 [x-client.example.com] # my Linux box dir:/usr/local/some-app Then if I run (typically by xymonclient.sh) this command: $XYMON $XYMSRV "client x-client.example.com.linux linux" or even something like: echo "client x-client.example.com.linux linux" | netcat xymon-server 1984 then not only will this send a client message to the server (in this case an empty one) but it will also output this: log:/var/log/messages:10240 # my Linux box dir:/usr/local/some-app (note that even the comments in clientlocal.cfg are included) The xymonclient.sh script grabs this output and sends it to a file in $XYMONTMP called "logfetch.$MACHINEDOTS.cfg". Every time a client message is sent, this file is updated. This file becomes the configuration file for logfetch, and is used on the next execution of xymonclient.sh. The xymon client and the netcat equivalent shown above produce these snippets from clientlocal.cfg for the logfetch config file, but only because they wait for remote data transmission after closing the local end of the socket. If using a telnet-based replacement for the Xymon client, you won't see the snippets, so this can't be used to configure the logfetch binary. If you want to run in central mode, you can discard the output of the xymon command that sends the client message, and just hard-code whatever settings you want in the client system's localclient.cfg file. Hope this explainifies this sufficiently for you. It should be noted that the logfetch binary will execute anything in backticks in a file: or log: entry that comes from the Xymon server. This provides a way for someone with write access to the xymonclient.cfg file on the Xymon server to execute arbitrary code on any and all Xymon clients. This presents a security risk, and as such, running logfetch in local mode may be preferable, or run with the "--noexec" option. For some situations, running logfetch at all is too much of a risk, and the loss of logfile monitoring is an acceptable cost. Cheers Jeremy On Tue, 4 Jun 2024 at 10:01, Grant Taylor via Xymon <xymon at xymon.com> wrote: > > > > ---------- Forwarded message ---------- > From: Grant Taylor <gtaylor at tnetconsulting.net> > To: xymon at xymon.com > Cc: > Bcc: > Date: Mon, 3 Jun 2024 18:59:17 -0500 > Subject: Re: [Xymon] Cross compilation > On 6/2/24 18:11, Jeremy Laidman wrote: > > Hi Grant > > Hi Jeremy, > > Thank you for your reply. > > > The log monitoring only requires the logfetch binary, which does > > three things: fetch the logs since the last time (and keep track of > > log file position), fetch file/dir status (permissions, ownership, > > hash if configured), and get the date and time of the client. You > > don't need xymonlaunch for monitoring logs. > > Thank you for clarifying. > > I hadn't noticed the lack of date and time. > > > Although, if running in central mode, you do need to capture the output > > of the xymon command that sends the client data message to the server, > > and save it to a file, because that's the config file for logfetch. > > Please elaborate. > > > I re-implemented the logfetch behaviour in my xymon-rcient.sh script > > (see Xymonton), consisting of about 3 functions and a bit of wrapper > > code, so it's possible to do without the binary if that option seems > useful. > > I'll have to check that out. > > > Alternatives for xymonlaunch are: > > - run xymonclient.sh from cron (perhaps via flock, or similar behaviour > > to ensure you don't ever get a backlog of client instantiations > > consuming system resources) > > That's what I'm doing currently. > > > - run via ssh from Xymon server to client, like: > > > > TMP=`mktemp`; echo "$MACHINE.$OSTYPE" > "$TMP" && ssh $MACHINE > > ~xymon/client/bin/xymonclient.sh && $XYMON 127.1 @ < "$TMP" >/dev/null; > > rm -f "$TMP" > > That's largely a non-starter for my particular environment for multiple > reasons. > > > (untested; also could do with flock or similar) > > ;-) > > The logic makes sense to me. > > > This can be run from a script launched by xymonlaunch on the Xymon > > server, rather than requiring a launcher on the client. > > So ... > > Will someone please give me pointers for how I can cross compile Xymon > client^W logfetch binary? > > > > -- > Grant. . . . > > > > ---------- Forwarded message ---------- > From: Grant Taylor via Xymon <xymon at xymon.com> > To: xymon at xymon.com > Cc: > Bcc: > Date: Mon, 3 Jun 2024 18:59:17 -0500 > Subject: Re: [Xymon] Cross compilation > _______________________________________________ > Xymon mailing list > Xymon at xymon.com > http://lists.xymon.com/mailman/listinfo/xymon >

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Cross compilation
by jeremy＠laidman.org 03 Jun '24

03 Jun '24

Hi Grant The log monitoring only requires the logfetch binary, which does three things: fetch the logs since the last time (and keep track of log file position), fetch file/dir status (permissions, ownership, hash if configured), and get the date and time of the client. You don't need xymonlaunch for monitoring logs. Although, if running in central mode, you do need to capture the output of the xymon command that sends the client data message to the server, and save it to a file, because that's the config file for logfetch. I re-implemented the logfetch behaviour in my xymon-rcient.sh script (see Xymonton), consisting of about 3 functions and a bit of wrapper code, so it's possible to do without the binary if that option seems useful. Alternatives for xymonlaunch are: - run xymonclient.sh from cron (perhaps via flock, or similar behaviour to ensure you don't ever get a backlog of client instantiations consuming system resources) - run via ssh from Xymon server to client, like: TMP=`mktemp`; echo "$MACHINE.$OSTYPE" > "$TMP" && ssh $MACHINE ~xymon/client/bin/xymonclient.sh && $XYMON 127.1 @ < "$TMP" >/dev/null; rm -f "$TMP" (untested; also could do with flock or similar) This can be run from a script launched by xymonlaunch on the Xymon server, rather than requiring a launcher on the client. Cheers Jeremy On Sun, 2 Jun 2024 at 09:05, Grant Taylor via Xymon <xymon at xymon.com> wrote: > > > > ---------- Forwarded message ---------- > From: Grant Taylor <gtaylor at tnetconsulting.net> > To: Xymon discuss <xymon at xymon.com> > Cc: > Bcc: > Date: Sat, 1 Jun 2024 17:55:09 -0500 > Subject: Cross compilation > Hi, > > Will someone please give me pointers for how I can cross compile Xymon > client? > > I've got some old AIX 5.3 systems that I'm using a hack to run the > xymonclient-aix.sh (from memory) and piping that into a script that > prefixes it with a header and connects to port 1984 of the Xymon server. > > I'd like to some client version of Xymon or older Hobbit compiled for > AIX 5.3. > > I'm mostly after the xymonlaunch / hobbitlaunch binary for AIX 5.3. I > think the bulk of the data comes from the xymonclient-aix.sh script. > But I'd like to start leveraging log file monitoring, which seems to > need the *launch binary. > > Thank you and have a good day. > > > > -- > Grant. . . . > > > > ---------- Forwarded message ---------- > From: Grant Taylor via Xymon <xymon at xymon.com> > To: Xymon discuss <xymon at xymon.com> > Cc: > Bcc: > Date: Sat, 1 Jun 2024 17:55:09 -0500 > Subject: [Xymon] Cross compilation > _______________________________________________ > Xymon mailing list > Xymon at xymon.com > http://lists.xymon.com/mailman/listinfo/xymon >

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Trends graph limit
by rower.master＠gmail.com 03 Jun '24

03 Jun '24

Hello All, Do trends column have a limitation in number of graphs to load? I can see that is stopping after loading 21 graphs. Is it configurable? My Xymon version is 4.3.30 Thanks in advance. Br, Mario

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Possible bug in xymon svcstatus causing segfault (buffer overrun?)
by jeremy＠laidman.org 03 Jun '24

03 Jun '24

Hi all I'm not a C programmer by any stretch, so I'm seeking confirmation that my working is sound. At our site we run 4.3.30-1 from Terabithia RPM. For most hosts, the "trends" page displays just fine, but for some hosts, the webserver gives a CGI error, and when I manually run the CGI directly it crashes with a seg fault. This seems to be more likely for hosts with a lot of entries on the trends page, but some with more trends graphs are OK than others with fewer. I believe I've tracked the issue down to the last few lines of code in svcstatus-trends.c, where a URL is constructed for one graph entry, before being added to the list of trends in a buffer. My reading of the code suggests that it first pre-allocates (using malloc()) a 16k buffer for the trends data, then sequentially appends trend strings (which include a URL) into the buffer, until the length of a string would exceed the size of the buffer. In that case, an extra 4k of memory is added to the buffer (using realloc()), and then the string is added to the buffer. The problem with the code, as I see it, is that the string might be more than 4k long, in which case, adding string would cause a buffer overrun. I don't really know what's in each string, so I don't know if it's ever likely to be 4k, but we're seeing the process dumping core immediately after this bit of code, so that's the suspicion. Here's the bit of code, which is attempting to add the string "onelink" to the buffer, after seeing if it's going to exceed the buffer, and extending the buffer if required: if ((buflen + strlen(onelink)) >= allrrdlinks_buflen) { SBUF_REALLOC(allrrdlinks, allrrdlinks_buflen+4096); allrrdlinksend = allrrdlinks + buflen; } allrrdlinksend += snprintf(allrrdlinksend, (allrrdlinks_buflen - (allrrdlinksend - allrrdlinks)), "%s", onelink); Elsewhere in other code, the SBUF_REALLOC macro is used to add extra bufferspace by calculating a new buffer size of [existing buffer size plus 4k plus the length of the string being added]. So if the string to be added had 20 bytes, SBUF_REALLOC would be used to add 4k+20 bytes to the buffer size. Notably, the size of the string is included in the calculation. For example this bit of code elsewhere in the same file does a similar buffer extension: if ((strlen(rrdlink) + strlen(partlink) + 1) >= rrdlink_buflen) { SBUF_REALLOC(rrdlink, rrdlink_buflen + strlen(partlink) + 4096); } strncat(rrdlink, partlink, (rrdlink_buflen - strlen(rrdlink))); Note the extra "+ strlen(<stringvar>)" bit in the extra memory being allocated that isn't there in the first block of code above. So my thinking is that the SBUF_REALLOC() needs to take the string's size into account, like so: SBUF_REALLOC(allrrdlinks, allrrdlinks_buflen+strlen(onelink)+4096); Is anyone with C skills able to confirm that this does indeed look like a bug, and also that my proposed change is a suitable fix? After applying this change and recompiling, we haven't yet seen a seg fault from this bit of code, so I'm hoping it's all fixed, and without negative side effects. Cheers Jeremy

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Cross compilation
by gtaylor＠tnetconsulting.net 01 Jun '24

01 Jun '24

Hi, Will someone please give me pointers for how I can cross compile Xymon client? I've got some old AIX 5.3 systems that I'm using a hack to run the xymonclient-aix.sh (from memory) and piping that into a script that prefixes it with a header and connects to port 1984 of the Xymon server. I'd like to some client version of Xymon or older Hobbit compiled for AIX 5.3. I'm mostly after the xymonlaunch / hobbitlaunch binary for AIX 5.3. I think the bulk of the data comes from the xymonclient-aix.sh script. But I'd like to start leveraging log file monitoring, which seems to need the *launch binary. Thank you and have a good day. -- Grant. . . .

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