flushing rrd files - now possible via rrdcached
Well - he is talking about starting 1.5 in the next few weeks... We are already using the head-branch in our production environment and it works without a lot of hickups. BUT: from all my testing it also requires a few patches to xymon to use fully qualified pathnames for rrdfiles to work properly. For us it now works fine and we are updating 32k rrd files via rrdcached every 5 minutes and with minimal IOWAITs... Ciao, Martin p.s: the config-settings we use now are: tasks.d/rrdcached: [rrdcache] LOGFILE $XYMONSERVERLOGS/rrdcached.log NEEDS xymond CMD /usr/bin/rrdcached -w 1800 -z 900 -f 3600 -l $XYMONVAR/rrdcached/rrdcached.socket -j $XYMONVAR/rrdcached -p $XYMONVAR/rrdcached/rrdcached.pid -g -l 0.0.0.0:41984 -b $XYMONVAR/ -B [rrdstatus] ENVFILE /usr/lib/xymon/server/etc/xymonserver-rrdcached.cfg CMD +--no-cache [rrddata] ENVFILE /usr/lib/xymon/server/etc/xymonserver-rrdcached.cfg CMD +--no-cache And /usr/lib/xymon/server/etc/xymonserver-rrdcached.cfg looks like this: include /usr/lib/xymon/server/etc/xymon/xymonserver.cfg RRDCACHED_ADDRESS="$XYRRDCACHED_ADDRESS" And the following added to /usr/lib/xymon/server/etc/xymon/xymonserver.cfg: XYRRDCACHED_ADDRESS="127.0.0.1:41984" RRDCACHED_STRIPPATH="$XYMONVAR" The reason why there is RRDCACHED only in the /usr/lib/xymon/server/etc/xymonserver-rrdcached.cfg is that otherwise it would do the flushing several times: Once for the global flushing of the host via rrd_cached_flush and then another time when creating the graph. This could possibly get consolidated if the existing caching solution in xymon is removed... Here the patch for the code: diff -ru xymon-4.3.17.orig/web/perfdata.c xymon-4.3.17/web/perfdata.c --- xymon-4.3.17.orig/web/perfdata.c 2012-07-23 04:47:20.000000000 -0700 +++ xymon-4.3.17/web/perfdata.c 2014-07-07 02:03:25.562153926 -0700 @@ -102,9 +102,11 @@ char *rrdargs[10]; int result; + char rrdfullname[2048]; + snprintf(rrdfullname,sizeof(rrdfullname),"%s/%s/%s",xgetenv("XYMONRRDS"),hostname,rrdname); rrdargs[0] = "rrdfetch"; - rrdargs[1] = rrdname; + rrdargs[1] = rrdfullname; rrdargs[2] = "AVERAGE"; rrdargs[3] = "-s"; rrdargs[4] = starttimedate; rrdargs[5] = starttimehm; rrdargs[6] = "-e"; rrdargs[7] = endtimedate; rrdargs[8] = endtimehm; diff -ru xymon-4.3.17.orig/web/showgraph.c xymon-4.3.17/web/showgraph.c --- xymon-4.3.17.orig/web/showgraph.c 2014-02-23 01:32:44.000000000 -0800 +++ xymon-4.3.17/web/showgraph.c 2014-07-07 05:19:39.314095689 -0700 @@ -119,6 +119,36 @@ exit(1); } +void rrd_cached_flush(char *hostname) { + /* the dir containing all the files */ + DIR *dirHandle; + struct dirent * dirEntry; + char dirName[PATH_MAX]; + char fileName[PATH_MAX]; + /* flushing cache */ + char *flush_args[4]; + flush_args[1]="--daemon"; + flush_args[2]=xgetenv("XYRRDCACHED_ADDRESS"); + flush_args[3]=fileName; + /* create fqdn */ + snprintf(dirName,sizeof(dirName),"%s/%s",xgetenv("XYMONRRDS"),hostname); + /* now iterate all the rrd files in this directory */ + dirHandle = opendir(dirName); + if (dirHandle) { + while((dirEntry = readdir(dirHandle))) { + int len=strlen(dirEntry->d_name); + if (strcmp(dirEntry->d_name+len-4,".rrd")==0) { + /* create final filename */ + snprintf(fileName,sizeof(fileName),"%s/%s", + dirName,dirEntry->d_name); + /* and flush */ + rrd_flushcached(4,flush_args); + } + } + closedir(dirHandle); + } +} + void request_cacheflush(char *hostname) { /* Build a cache-flush request, and send it to all of the $XYMONTMP/rrdctl.* sockets */ @@ -128,6 +158,9 @@ struct dirent *d; int ctlsocket = -1; + if (xgetenv("XYRRDCACHED_ADDRESS")) + return rrd_cached_flush(hostname); + ctlsocket = socket(AF_UNIX, SOCK_DGRAM, 0); if (ctlsocket == -1) { errprintf("Cannot get socket: %s\n", strerror(errno)); diff -ru xymon-4.3.17.orig/xymond/do_rrd.c xymon-4.3.17/xymond/do_rrd.c --- xymon-4.3.17.orig/xymond/do_rrd.c 2013-08-25 07:03:44.000000000 -0700 +++ xymon-4.3.17/xymond/do_rrd.c 2014-07-07 04:41:33.635681424 -0700 @@ -245,9 +246,10 @@ /* * RRDtool 1.2+ uses mmap'ed I/O, but the Linux kernel does not update timestamps when * doing file I/O on mmap'ed files. This breaks our check for stale/nostale RRD's. - * So do an explicit timestamp update on the file here. + * So do an explicit timestamp update on the file here if we are not using rrdcache */ - utimes(filedir, NULL); + if (!xgetenv("RRDCACHED_ADDRESS")) + utimes(filedir, NULL); #endif /* Clear the cached data */
-----Original Message----- From: J.C. Cleaver [mailto:cleaver at terabithia.org] Sent: Mittwoch, 03. September 2014 18:28 To: Martin Sperl Subject: Re: [Xymon] flushing rrd files - now possible via rrdcached
Hello!
Not sure if you'd been following along on your original commit at https://github.com/oetiker/rrdtool-1.x/pull/462, but I'd expressed interest to T. Oetiker on possibly getting this into 1.4.x for the next possible release. After he requested a pull, I noticed a few build problems (aside from the patch not directly applying) with it on the current 1.4.x branch.
If you have a chance, I was wondering if you might be able to take look at setting up a pull for him? Figure since you wrote it you'd be more familiar with what exactly's going wrong... :)
Let me know if I can be of any help!
Regards, -jc
On 7 May 2014 08:54, Martin Sperl <Martin.Sperl at amdocs.com> wrote:
There now exists a patch to rrdtool (which has already been merged) that allows xymon to work with the following config-changes:
[rrdcache] LOGFILE $XYMONSERVERLOGS/rrdcached.log NEEDS xymond CMD $RRD_BASE/bin/rrdcached -w 1800 -z 900 -f 1800 -l $XYMONVAR/rrdcached/rrdcached.socket -j $XYMONVAR/rrdcached -p $XYMONVAR/rrdcached/rrdcached.pid -g -l 0.0.0.0:41984 -b $XYMONVAR/ -B
[rrdstatus] CMD +--no-cache [rrddata] CMD +--no-cache
And in the ENVFILE /etc/xymon/xymonserver.cfg add: RRDCACHED_ADDRESS="127.0.0.1:41984" RRDCACHED_STRIPPATH="$XYMONVAR" # these are there to override the default rrd install location # so that it uses the head build from rrdtool RRD_BASE="/opt/rrdtool-1.4.999" LD_LIBRARY_PATH="$RRD_BASE/lib/"
The patch to rrdtool: https://github.com/oetiker/rrdtool-1.x/pull/462 has already been incorporated with the main development branch, so I hope it will get into the next rrdtool-1.4 release.
Ciao, Martin
From: Xymon [mailto:xymon-bounces at xymon.com] On Behalf Of Martin Sperl Sent: Dienstag, 29. April 2014 13:03 To: Jeremy Laidman Cc: xymon at xymon.com Subject: Re: [Xymon] flushing rrd files
Thanks - the problem is that those sockets change so you have to "guess" their path and see if it is functional (as with your perl example - in my case there are actually 16 socket files in temp and I have to iterate over all of them to find the 2 that are actually working - slightly stupid...)
Obviously this also does not work from a remote node which only has access to the rrd files via NFS... Meaning I have to write a http proxy for that...
So I was wondering if xymond_rrd with the --no-cache would use the RRDCache if set in the environment. My guess would be I need to use a different env file which has RRDCACHED_ADDRESS set correctly (which rrdtool makes use of automatically if the ENV is set) and then configure xymond_rrd to use that environment instead.... If that works then that rrd-specific caching could get removed as a whole - with the exception of the need for
I just want to avoid testing this on our live system, so I was asking if anyone has experience with this...
Martin
From: Jeremy Laidman [mailto:jlaidman at rebel-it.com.au] Sent: Dienstag, 29. April 2014 04:33 To: Martin Sperl Cc: xymon at xymon.com<mailto:xymon at xymon.com> Subject: Re: [Xymon] flushing rrd files
I think work would need to be done to integrate with rrdcached.
The RRD stats are cached by xymond_rrd. The showgraph.cgi binary sends a flush command to the xymond_rrd instances, via UNIX sockets, requesting a cache flush, so that graphs are up-to-date. You could probably emulate this by running showgraph.cgi from the command-line. Like so:
SCRIPT_NAME=showgraph.sh REQUEST_METHOD=GET QUERY_STRING="host=hostname.example.com<http://hostname.example.co m>&service=conn" /usr/lib/xymon/server/bin/showgraph.cgi >/dev/null
In this case, the "conn" is not used for anything (all RRD files are flushed), but has to be a (I think) valid RRD filename (without the extension) or graph name (defined in graphs.cfg).
Also, if you can send a string directly to the two UNIX sockets, you can cause a flush. The format is simply the hostname in slashes, like "/hostname.example.com<http://hostname.example.com>" and so you can probably achieve this using modern versions netcat or socat, or other things that can write to sockets.
And just for fun, here's an implementation in Perl.
Cheers Jeremy
#!/usr/bin/perl -Tw
my $hostname=shift; die "Specify hostname\n" unless defined($hostname);
my $socketdir=$ENV{XYMONTMP}; die "XYMONTMP not defined, run from xymoncmd\n" unless $socketdir;
use Socket; socket(SOCK, AF_UNIX, SOCK_DGRAM, 0) or die "socket: $!\n"; use Fcntl qw(F_GETFL F_SETFL O_NONBLOCK); my $flags = fcntl(SOCK, F_SETFL, O_NONBLOCK) or die "fcntl: $!\n";
opendir(DIR,$socketdir) or die "$!: $socketdir\n"; while(my $socketfile=readdir(DIR)) { next unless substr($socketfile,0,7) eq "rrdctl."; my $socketpath="$socketdir/$socketfile"; if (! -e $socketpath) { warn "not found: $socketpath\n"; next; } if (! -w $socketpath) { warn "not writeable: $socketpath\n"; next; } if (! -S $socketpath) { warn "not a socket: $socketpath\n"; next; }
$socketaddr=sockaddr_un($socketpath);
if (defined(send(SOCK, "/$hostname/", 0, $socketaddr))) { print "Flush command for '$hostname' sent to $socketfile\n"; } else { warn "Flush command for '$hostname' failed to send to socket $socketfile\n"; } }
On 25 April 2014 22:29, Martin Sperl <Martin.Sperl at amdocs.com<mailto:Martin.Sperl at amdocs.com>> wrote: Hi!
Is there a means to flush the rrd files filled in from xymond_rrd say via the "xymon" command?
As an alternative is it possible to use the generic RRDCACHED as a replacement for the caching? Any experience with that?
Thanks, Martin
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