[hobbit] RRD crashing high availability hobbit
David Baldwin
david.baldwin at ausport.gov.au
Fri Aug 21 01:42:59 CEST 2009
j.sansford at ntlworld.com wrote:
> Hi Buchan,
>
> We get a core dump, running a pstack gives the following info:
>
> core 'core' of 11142: hobbitd_rrd --rrddir=/export/home/hobbit/data/rrd
> fed28a17 _lwp_kill (1, 6) + 7
> fecd1d63 raise (6) + 1f
> fecb1bad abort (806fe88, fecd55f6, 8768eb0, 806a6ca, fed901c0, 0) + cd
> 08060291 xstrdup (0, 806a6ca, 87d9d1c, 8081cc0, 84ed451, 0) + 31
> 0805bf7c do_netapp_extratest_rrd (84ec4ff, 806af10, 84ec8fa, 4a8b1bbf, 8081a00, 8081cc0) + 200
> 0805c1c9 do_netapp_extrastats_rrd (84ec4ff, 84ec509, 84ec511, 4a8b1bbf, 84ec4f4, 4a8b1bbf) + e1
> 0805e0ea update_rrd (84ec4ff, 84ec509, 84ec511, 4a8b1bbf, 84ec4f4, 0) + 7d6
> 08054044 main (2, 804613c, 8046148) + 4dc
> 080539fc _start (2, 8046484, 8046490, 0, 80464b6, 80464f6) + 80
>
>
That looks like you are running extratest for a netapp which from what I
can see in hobbitd/do_rrd.c is what handles the xtstats column reported
by netapp.pl - just from a cursory glance at the code - I don't use it
myself. You really need to look at the C code to check it's doing the
right thing. You have 2 choices - quick fix is to disable just that test
in netapp.pl - other option is to work out what format it should be and
fix the test.
In 4.2.3 for example, the do_devmon.c RRD code doesn't actually
implement what is documented and I use a perl script with --extra-script
instead
Various RRD handlers are in hobbitd/rrd/do_*.c
Looking at the code for xstrdup in lib/memory.c as below you should
check your logs - it's probably getting called with a NULL pointer
(unlikely you're out of memory), but the logs should tell you.
char *xstrdup(const char *s)
{
char *result;
if (s == NULL) {
errprintf("xstrdup: Cannot dup NULL string\n");
abort();
}
result = strdup(s);
if (result == NULL) {
errprintf("xstrdup: Out of memory\n");
abort();
}
#ifdef MEMORY_DEBUG
add_to_memlist(result, strlen(result)+1);
#endif
return result;
}
> Note that as of 5.30pm today the logs for rrd-status.log is 127MB full of errors, which span over 607625 lines (this is just for today, we roll the logs each night). This seems abnormally large to me and I think eventually this is crashing the server.
>
> Hope this helps. I will try and take a deeper look at the logs next time it happens...it seems to happen around once or twice a week.
>
> Cheers
> James.
>
> ---- Buchan Milne <bgmilne at staff.telkomsa.net> wrote:
>
>> On Thursday, 20 August 2009 11:06:30 j.sansford at ntlworld.com wrote:
>>
>>> Hi again all,
>>>
>>> I need some help configuring/debugging why our hobbit servers are crashing
>>> (due to rrd, which I shall explain shortly) and how to get around this. We
>>> have 3 hobbit servers with proxies, however I will simplify this
>>> explanation with just 2 hobbits and no proxies (as we discovered the same
>>> thing happens).
>>>
>>> Detail of theoretical setup:
>>>
>>> 1) 2 datacentres. Each datacentre contains a single hobbit server instance.
>>> 2) Each client reports to their local datacentre hobbit server.
>>> 3) Each hobbit server is configured such that they know about the other
>>> hobbit (through BBDISPLAYS).
>>>
>>>
>>> The issue is that for what looks like most server side tests, such as
>>> vmstat etc, that we are getting feedback loops between the hobbit servers.
>>>
>>> For instance: A hobbit server in DC1 tests a client in DC1 using vmstat.
>>> The client reports back to hobbit in DC1 and hobbit then also reports this
>>> data to the hobbit in DC2. The hobbit in DC2 however is configured to
>>> report to DC1 and so bounces the message back (i think). Therefore the
>>> server tries to update the rrd twice within a second resulting in errors.
>>> Eventually this will crash the server.
>>>
>> How did you determine that this is what is "crashing" the server?
>>
>>
>>> An example of the rrd error
>>> messages:
>>>
>>> 2009-08-20 11:04:04 RRD error updating
>>> /export/home/hobbit/data/rrd/h3-avm-dbx/ifstat.mac.rrd from 10.6.60.1:
>>> illegal attempt to update using time 1250762644 when last update time is
>>> 1250762644 (minimum one second step)
>>> 2009-08-20 11:04:06 RRD error updating
>>> /export/home/hobbit/data/rrd/h2-emu13/ifstat.mac.rrd from 10.6.60.1:
>>> illegal attempt to update using time 1250762646 when last update time is
>>> 1250762646 (minimum one second step) 2009-08-20 11:04:06 RRD error updating
>>> /export/home/hobbit/data/rrd/h2-emu13/ifstat.mac.rrd from 10.6.60.1:
>>> illegal attempt to update using time 1250762646 when last update time is
>>> 1250762646 (minimum one second step) 2009-08-20 11:04:06 RRD error updating
>>> /export/home/hobbit/data/rrd/h2-emu13/ifstat.mac.rrd from 10.6.60.1:
>>> illegal attempt to update using time 1250762646 when last update time is
>>> 1250762646 (minimum one second step)
>>>
>> I have a number of setups where messages like this are common, due to running
>> network tests and SNMP polling at intervals smaller than 5 minutes (without
>> adjusting all the RRD files to cater to this), and I have not seen hobbit
>> "crash" due to this.
>>
>>
These kinds of messages can also be due to duplicate keys being used in
RRD reporting. You need to look at how the RRD data is generated to get
to the bottom of these. Sometimes the duplicates are in one test,
sometimes multiple tests reporting the same thing or too frequently
(such as your possible loops). It is unlikely thsi will crash the
hobbitd_rrd though.
For example, I had this on MacOSX for ifstat. By default it uses
'netstat -ibn' which is producing multiple lines for the same interface.
I changed that in hobbitclient-darwin.sh to 'netstat -ibn | egrep -v
"^lo|^vmnet|<Link" - note that I had to filter out vmnet interfaces
since netstat -i limits to 5 chars for interface, and there are actually
vmnet1 and vmnet8 :( Luckily I don't really care about those.
bash-3.2# netstat -ibn | egrep -v "^lo|^vmnet|<Link"
Name Mtu Network Address Ipkts Ierrs Ibytes
Opkts Oerrs Obytes Coll
en0 1500 fe80::21f:f fe80:6::21f:f3ff: 7709215 - 2307390372
23616260 - 32787591390 -
en0 1500 10.1/16 10.1.75.6 7709215 - 2307390372
23616260 - 32787591390 -
en2 1500 fe80::201:2 fe80:9::201:23ff: 0 -
0 0 - 781938 -
en2 1500 10.37.129/24 10.37.129.2 0 -
0 0 - 781938 -
en3 1500 fe80::210:3 fe80:a::210:32ff: 0 -
0 0 - 792748 -
en3 1500 10.211.55/24 10.211.55.2 0 -
0 0 - 792748 -
bash-3.2# netstat -ibn
Name Mtu Network Address Ipkts Ierrs Ibytes
Opkts Oerrs Obytes Coll
lo0 16384 <Link#1> 196623 0 20477947
196620 0 20477947 0
lo0 16384 fe80::1%lo0 fe80:1::1 196623 - 20477947
196620 - 20477947 -
lo0 16384 127 127.0.0.1 196623 - 20477947
196620 - 20477947 -
lo0 16384 ::1/128 ::1 196623 - 20477947
196620 - 20477947 -
gif0* 1280 <Link#2> 0 0
0 0 0 0 0
stf0* 1280 <Link#3> 0 0
0 0 0 0 0
en1 1500 <Link#4> 00:1f:5b:c3:ec:35 0 0
0 0 0 0 0
fw0 4078 <Link#5> 00:1f:f3:ff:fe:71:5e:18 0 0
0 0 0 346 0
en0 1500 <Link#6> 00:1f:f3:5c:32:e6 7709242 0 2307393391
23616262 0 32787591586 0
en0 1500 fe80::21f:f fe80:6::21f:f3ff: 7709242 - 2307393391
23616262 - 32787591586 -
en0 1500 10.1/16 10.1.75.6 7709242 - 2307393391
23616262 - 32787591586 -
vmnet 1500 <Link#7> 00:50:56:c0:00:08 0 0
0 0 0 0 0
vmnet 1500 192.168.149 192.168.149.1 0 -
0 0 - 0 -
vmnet 1500 <Link#8> 00:50:56:c0:00:01 0 0
0 0 0 0 0
vmnet 1500 172.16.189/24 172.16.189.1 0 -
0 0 - 0 -
en2 1500 <Link#9> 00:01:23:45:67:89 0 0
0 0 0 781938 0
en2 1500 fe80::201:2 fe80:9::201:23ff: 0 -
0 0 - 781938 -
en2 1500 10.37.129/24 10.37.129.2 0 -
0 0 - 781938 -
en3 1500 <Link#10> 00:10:32:54:76:98 0 0
0 0 0 792748 0
en3 1500 fe80::210:3 fe80:a::210:32ff: 0 -
0 0 - 792748 -
en3 1500 10.211.55/24 10.211.55.2 0 -
0 0 - 792748 -
>> What is the behaviour you see when it "crashes the server" ? Does hobbitd_rrd
>> die and leave a status message? Or, does something else occur? Does the server
>> reboot? Does the OS hang? How often does this occur?
>>
>>
>>> My question is - how can we stop this happening?
>>>
>> You would first need to tell us what is happening ...
>>
>>
>>> Also, why is this
>>> happening? Is there a way we can disable rrd graphing on one server so just
>>> one hobbit server handles the graphing?
>>>
>>> I hope that makes sense. If you need further clarification please let me
>>> know.
>>>
>> If hobbitd or hobbitd_rrd or some other process actually crashes, you should
>> be able to get a core file, from which you can get a backtrace (e.g. with gdb),
>> which would allow someone to see why it is crashing, and possibly fix it.
>>
>> Regards,
>> Buchan
>>
>
>
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> hobbit-unsubscribe at hswn.dk
>
>
>
--
David Baldwin - IT Unit
Australian Sports Commission www.ausport.gov.au
Tel 02 62147830 Fax 02 62141830 PO Box 176 Belconnen ACT 2616
david.baldwin at ausport.gov.au Leverrier Street Bruce ACT 2617
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