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Thursday, June 12. 2008Monitoring Xen via SNMP - updateIn a previous post, Monitoring Xen via SNMP, I documented a method for monitoring xens from dom0. This article shows a few improvements and bug fixes, and allows for monitoring a 'cloud' of domains.
Please view http://run.tournament.org.il/xen-vms-performance-collection/ for an updated version
The perl scripts posted before where buggy, here's an improved version: For Xen 3.1 #!/usr/bin/perl -w use strict; # declare... sub trim($); # we need to run 2 itterations because CPU stats show 0% on the first, and I'm putting .1 second betwen them to speed it up my @result = split(/\n/, `xentop -b -i 2 -d.1`); # remove the first line shift(@result); shift(@result) while @result && $result[0] !~ /^xentop - /; # the next 3 lines are headings.. shift(@result); shift(@result); shift(@result); shift(@result); foreach my $line (@result) { my @xenInfo = split(/[\t ]+/, trim($line)); printf("name: %s, cpu_sec: %d, cpu_percent: %.2f, vbd_rd: %d, vbd_wr: %d\n", $xenInfo[0], $xenInfo[2], $xenInfo[3], $xenInfo[14], $xenInfo[15] ); } # trims leading and trailing whitespace sub trim($) { my $string = shift; $string =~ s/^\s+//; $string =~ s/\s+$//; return $string; } For Xen 3.2 #!/usr/bin/perl -w use strict; # declare... sub trim($); # we need to run 2 itterations because CPU stats show 0% on the first, and I'm putting .1 second betwen them to speed it up my @result = split(/\n/, `xentop -b -i 2 -d.1`); # remove the first line shift(@result); shift(@result) while @result && $result[0] !~ /^[\t ]+NAME/; shift(@result); foreach my $line (@result) { my @xenInfo = split(/[\t ]+/, trim($line)); printf("name: %s, cpu_sec: %d, cpu_percent: %.2f, vbd_rd: %d, vbd_wr: %d\n", $xenInfo[0], $xenInfo[2], $xenInfo[3], $xenInfo[14], $xenInfo[15] ); } # trims leading and trailing whitespace sub trim($) { my $string = shift; $string =~ s/^\s+//; $string =~ s/\s+$//; return $string; } Another change I made was to run this script though cron, removing the need for sudo. Here's my crontab: * * * * * root /usr/local/bin/xen_stats.pl > /tmp/xen-stats.new && mv /tmp/xen-stats.new /var/run/xen-stats And the updated snmpd.conf: extend xen-stats /bin/cat /var/run/xen-stats I've attached some cacti stuff again, this time you will need to modify the file 'scripts/xen_cloud_stats.php' - it contains an array of your xen servers. The script uses APC (if available) to cache the SNMP data for 10 seconds, as cacti will call this script lots of times in the process of updating the RRDs every 5 minutes. The physical server your domains are on is hidden from cacti using this system - this is how I wanted it was we have automatic migrations going on. xen_cloud.tar.gzTrackbacks
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Hi,
I am missing something.. but I try not to think too hard about PHP: + Executing script query '/usr/bin/php /usr/share/cacti/site/scripts/xen_cloud_stats.php query xen_name' + Found item [xen_name=' Call to undefined function snmp_set_valueretrieval() in /usr/share/cacti/site/scripts/xen_cloud_stats.php on line 73'] index: Fatal error
Your PHP install doesn't have SNMP support. Install the module, or recompile, or whatever you need to do for your chosen distro
wow i'm a complete doofus!
thanks - did i mention that?
Hello,
I have installed cacti to make use of your work here. When i try to import the template 'cacti_data_query_xen_cloud.xml' file into cacti i get an error: "Error: XML: Hash version does not exist." Also if i run the command from the previos posts: '/usr/bin/php /usr/share/cacti/site/scripts/xen_cloud_stats.php query xen_name' i get the error: "Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /usr/share/cacti/site/scripts/xen_cload_stats.php on line 27" am i missing something?
if you're trying to use PHP4, that would probably explain it. I'm not sure I do anything that's specifically PHP4, but I WILL NEVER write PHP4 compatable code ever again
 I've no idea what the hash problem is about, if you can't get it working drop me a mail for my consultancy rates. Good luck!
I am trying to gauge how stressed the physical CPU is on any one dom0.
If I were to add a TOTAL cdef on the cpu_sec, would it all add up to 1 second on average - for a single core system? and 4 seconds for a quad core? I have the graph - but I can't share it with you here.. C.
Hi Ian.
I'm using Xen 3.1 on FC8 and I can't do your template works for my Cacti. Could you help me? I've done everything you said here on Dom0. That's right? Do I have to do something on DomUs? I would be very grateful if you could help me by mail. I'll use it in my Graduation Project. Thanks!
Due to a change in my blog, the new address is above.
I wanted to update this page. Thanks! Ez-Aton |
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