Great work Christoph.
Sorry, it appears that I led you down the wrong path, asserting that it was a server-only setting in xymond. It would appear to be a client-side setting. This seems to be undocumented in the man page for xymonclient.cfg.
J
On Thu, 10 Mar 2022 at 21:18, Christoph Zechner <zechner at vrvis.at> wrote:
I solved it!
I had to add and set "MAXMSG_CLIENT=1024" in /etc/xymon/xymonclient.cfg, restarted xymon-client and all the errors were gone.
Thanks again for your help!
Cheers Christoph
On 09/03/2022 06:42, Christoph Zechner wrote:
On 09/03/2022 00:04, Jeremy Laidman wrote:
On Tue, 8 Mar 2022 at 18:52, Christoph Zechner <zechner at vrvis.at <mailto:zechner at vrvis.at>> wrote:
It seems I celebrated prematurely, the errors are back in exactlythe same way :-/
2022-03-08 08:47:19.321457 Got over-size message, truncating at528383 bytes (max: 524288) 2022-03-08 08:47:19.339786 Dropping (more) garbled data
I don't understand where this limit 05 512 comes from, everything on the server checks out (2048 before, tried 4096 as well, no change).I'm at a loss. If the xymond process is proven to have this set at 2048, then I see no reason why it would give that error message with that number.
Unless it's referring to another message type and hence a different maximum setting? Perhaps take a look at xymond's environment again, but search for all MAXMSG_ variables. See which one is set to 512, and that might be the culprit. The defaults for these max values are all different, with only two of them defaulting to 512: MAXMSG_CLIENT, MAXMSG_CLICHG (reference: lib/xymond_buffer.c). But it's possible one of them has been set to 512.
Thanks, I tried that, but unfortunately, this did not help, since all the values were set correctly, according to my config.
The only other thing I can think of is that you have two copies of xymond running, somehow with different values of MAXMSG_CLIENT. But I can't think how this could come about. And you've already killed off any rogue processes.
Right, that's not it either. :-/
Maybe run xymond in debug mode for one round of updates, until you get the "Got over-size message" and review the debug logs. This might provide enough additional detail to find out what's going on.
Another approach to solve the problem (truncated client data message) is to modify the client script (eg xymonclient-linux.sh) to truncate the ps command output, so that the total message size is less, and hopefully fits within the max message size. This will mean that PROC checks might not work anymore (which is likely the case now). But the current state is that monitoring of the sections that come after [ps] are likely broken now. On Linux this is notably the [top] and [vmstat] sections of the client data message, that are used for the "cpu" status and several metrics for graphing. Maybe something like adding "head -1000" will cut it down to a reasonable size:
echo "[ps]" ps -Aww -o pid,ppid,user,start,state,pri,pcpu,time,pmem,rsz,vsz,cmd | head -1000
That's actually a gread idea and I modified the [ports] section, because I know this is the culprit (running a proxy there and all the active client connections were too much for xymon to handle.
I'm not interested in client connections anyway, I just want to monitor my running programs and ports on that server, so I replaced the original
netstat -antuW 2>/dev/null netstat -antuT 2>/dev/null
with
netstat -tulpenW 2>/dev/null
(adding your "| head 1000" suggestion did not work, because it cut off the list before it could reach the IPv6 interfaces and thus the ports check was always red).
Now xymon works again, although this is just a workaround, because the underlying problem of where exactly my messages got truncated, is still to be found, but I can live with this solution.
Anyway, I very much appreciate your time and efforts, thank you very much!
Cheers Christoph
Also, review the client data message before the [ps] section to see if there's actually something else pushing it over the limit, and [ps] just happens to be where the truncation happens.
J
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