28 Jul
2010
28 Jul
'10
5:29 p.m.
Hi, finally I've discovered the cause of important issues with my
Kamailio deployments which sometimes get frozen "with no reason":
- We use Debian Lenny with rsyslog writting the logs in local files
(/var/log/kamailio.log) and also rsyslog-mysql extension to send the
logs to a remote MySQL server using mysql TCP protocol.
- For "external" reason (external to me) such MySQL server sometimes
fails or it's down.
- Then kamailio tries to log to syslog. rsyslog receives the request
and tries to send it via MySQL. Unfortunatelly it gets frozen as the
DB doesn't work, and it neither writes the log to the local log file
!!! (this is really surprising to me).
- Worse is the fact the rsyslog replies nothing to kamailio process so
the kamailio process gets 100% *blocked* waiting for the response
(this is what I suspect).
- As a dirty workaround, stopping the local rsyslog server makes
kamailio to work again.
So, I think this is mostly a bug in rsyslog-mysql as it shouldn't get
frozen if the MySQL server doesn't work. However I also think that
Kamailio should not depend on it, and perhaps it shouldn't wait
indefinitely for the rsyslog response. What do you think?
Would make sense a "ping" mechanism like with RtpProxy servers in
order to enable/dissable the syslog logging?
Regards.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
28 Jul
28 Jul
5:36 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
El Wed, 28 Jul 2010 17:29:42 +0200
Iñaki Baz Castillo <ibc(a)aliax.net> escribió:
- Then kamailio tries to log to syslog. rsyslog
receives the request
and tries to send it via MySQL. Unfortunatelly it gets frozen as the
DB doesn't work, and it neither writes the log to the local log file
!!! (this is really surprising to me).
If the entry for mysql is before the entry for the local file, it's not
surprising.
- Worse is the fact the rsyslog replies nothing to kamailio process so
the kamailio process gets 100% *blocked* waiting for the response
(this is what I suspect).
- As a dirty workaround, stopping the local rsyslog server makes
kamailio to work again.
A better workaround is to have queue support in rsyslog. Messages are stored in
memory and in a disk queue and they are pushed to the db when the
connection is recovered.
Try something like this in your rsyslog.conf configuration:
# Memory and disk Queuing support
$WorkDirectory /var/log/queue
$ActionQueueType LinkedList
$ActionQueueFileName SL
$ActionQueueMaxDiskSpace 4g
$ActionQueueSaveOnShutdown on
$ActionResumeRetryCount -1
So, I think this is mostly a bug in rsyslog-mysql as it shouldn't get
frozen if the MySQL server doesn't work. However I also think that
Kamailio should not depend on it, and perhaps it shouldn't wait
indefinitely for the rsyslog response. What do you think?
Would make sense a "ping" mechanism like with RtpProxy servers in
order to enable/dissable the syslog logging?
I think this is not kamailio's fault. Kamailio just uses syslog services and
it's up to syslog server to be fault tolerant.
My $0,02
5:41 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
28 jul 2010 kl. 17.36 skrev Jon Bonilla (Manwe):
El Wed, 28 Jul 2010 17:29:42 +0200
Iñaki Baz Castillo <ibc(a)aliax.net> escribió:
THis is great advice, thanks!
Found these docs:
http://www.rsyslog.com/doc/queues.html
/O
- Then kamailio tries to log to syslog. rsyslog
receives the request
and tries to send it via MySQL. Unfortunatelly it gets frozen as the
DB doesn't work, and it neither writes the log to the local log file
!!! (this is really surprising to me).
If the entry for mysql is before the entry for the local file, it's not
surprising.
- Worse is the fact the rsyslog replies nothing to kamailio process so
the kamailio process gets 100% *blocked* waiting for the response
(this is what I suspect).
- As a dirty workaround, stopping the local rsyslog server makes
kamailio to work again.
A better workaround is to have queue support in rsyslog. Messages are stored in
memory and in a disk queue and they are pushed to the db when the
connection is recovered.
Try something like this in your rsyslog.conf configuration:
# Memory and disk Queuing support
$WorkDirectory /var/log/queue
$ActionQueueType LinkedList
$ActionQueueFileName SL
$ActionQueueMaxDiskSpace 4g
$ActionQueueSaveOnShutdown on
$ActionResumeRetryCount -1
5:52 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
2010/7/28 Jon Bonilla <manwe(a)aholab.ehu.es>es>:
El Wed, 28 Jul 2010 17:29:42 +0200
Iñaki Baz Castillo <ibc(a)aliax.net> escribió:
Awesoming!
I'll test your suggested configuration. Thanks a lot.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
- Then kamailio tries to log to syslog. rsyslog
receives the request
and tries to send it via MySQL. Unfortunatelly it gets frozen as the
DB doesn't work, and it neither writes the log to the local log file
!!! (this is really surprising to me).
If the entry for mysql is before the entry for the local file, it's not
surprising.
- Worse is the fact the rsyslog replies nothing to kamailio process so
the kamailio process gets 100% *blocked* waiting for the response
(this is what I suspect).
- As a dirty workaround, stopping the local rsyslog server makes
kamailio to work again.
A better workaround is to have queue support in rsyslog. Messages are stored in
memory and in a disk queue and they are pushed to the db when the
connection is recovered.
Try something like this in your rsyslog.conf configuration:
# Memory and disk Queuing support
$WorkDirectory /var/log/queue
$ActionQueueType LinkedList
$ActionQueueFileName SL
$ActionQueueMaxDiskSpace 4g
$ActionQueueSaveOnShutdown on
$ActionResumeRetryCount -1
5:39 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
28 jul 2010 kl. 17.29 skrev Iñaki Baz Castillo:
Hi, finally I've discovered the cause of important
issues with my
Kamailio deployments which sometimes get frozen "with no reason":
- We use Debian Lenny with rsyslog writting the logs in local files
(/var/log/kamailio.log) and also rsyslog-mysql extension to send the
logs to a remote MySQL server using mysql TCP protocol.
- For "external" reason (external to me) such MySQL server sometimes
fails or it's down.
- Then kamailio tries to log to syslog. rsyslog receives the request
and tries to send it via MySQL. Unfortunatelly it gets frozen as the
DB doesn't work, and it neither writes the log to the local log file
!!! (this is really surprising to me).
- Worse is the fact the rsyslog replies nothing to kamailio process so
the kamailio process gets 100% *blocked* waiting for the response
(this is what I suspect).
- As a dirty workaround, stopping the local rsyslog server makes
kamailio to work again.
So, I think this is mostly a bug in rsyslog-mysql as it shouldn't get
frozen if the MySQL server doesn't work. However I also think that
Kamailio should not depend on it, and perhaps it shouldn't wait
indefinitely for the rsyslog response. What do you think?
Would make sense a "ping" mechanism like with RtpProxy servers in
order to enable/dissable the syslog logging?
Syslog is defined in http://tools.ietf.org/html/rfc5424, but I can't find
anything there about this situation. It's a simplex protocol, so the implementation
should propably handle this situation, as you say, rsyslog is at fault here.
If it does, we need to figure out a way so that Kamailio doesn't lock up
if this happens, not logging in the same process or thread or something...
/O
5:44 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
2010/7/28 Olle E. Johansson <oej(a)edvina.net>et>:
Syslog is defined in
http://tools.ietf.org/html/rfc5424, but I can't find
anything there about this situation. It's a simplex protocol, so the implementation
should propably handle this situation
Note that we don't use the "syslog remote protocol" as defined in RFC
5424. Kamailio logs to the local rsyslog server and rsyslog logs to a
local file(s) and also performs a SQL query to store the log in a
MySQL server.
If it does, we need to figure out a way so that
Kamailio doesn't lock up
if this happens, not logging in the same process or thread or something...
Being a multiprocess blocking design it would be a bit difficult such
solution. Perhaps the "ping syslog" mechanism I suggested in my
initial mail :)
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
5:52 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
28 jul 2010 kl. 17.44 skrev Iñaki Baz Castillo:
I thought it wasn't easy... But still, we need some sort of solution
since this can affect a lot of systems.
/O
2010/7/28 Olle E. Johansson <oej(a)edvina.net>et>:
Ahh.
Syslog is defined in
http://tools.ietf.org/html/rfc5424, but I can't find
anything there about this situation. It's a simplex protocol, so the implementation
should propably handle this situation
Note that we don't use the "syslog remote protocol" as defined in RFC
5424. Kamailio logs to the local rsyslog server and rsyslog logs to a
local file(s) and also performs a SQL query to store the log in a
MySQL server. If it does, we need to figure out a way so that
Kamailio doesn't lock up
if this happens, not logging in the same process or thread or something...
Being a multiprocess blocking design it would be a bit difficult such
solution. Perhaps the "ping syslog" mechanism I suggested in my
initial mail :)
10:18 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
2010/7/28 Olle E. Johansson <oej(a)edvina.net>et>:
Let me suggest this proposal:
- Having a dedicated kamailio process to act as syslogger.
- Other kamailio processes send logging messages to such syslogger
process by using a posix queue fifo which is non blocking. This means
that kamailio workers would never wait for the "syslog()" call to
return.
- Posix mesage queues implement a configurable queue. But also, the
syslogger process could manage its own queue (by using an array as a
FIFO system) so messages received by the posix queue would be
inserted in the FIFO and extracted from there when they are logged to
syslog.
- In this way, if syslog daemon gets frozen kamailio workers wouldn't
realize of it. Some logs would be lost in case the FIFO gets full but
this is not so important as getting Kamailio non processing SIP
messages :)
Opinnions? Do you consider it feasible?
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
Being a
multiprocess blocking design it would be a bit difficult such
solution. Perhaps the "ping syslog" mechanism I suggested in my
initial mail :)
I thought it wasn't easy... But still, we need some sort of solution
since this can affect a lot of systems.
10:27 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
28 jul 2010 kl. 22.18 skrev Iñaki Baz Castillo:
2010/7/28 Olle E. Johansson <oej(a)edvina.net>et>:
Let me suggest this proposal:
- Having a dedicated kamailio process to act as syslogger.
- Other kamailio processes send logging messages to such syslogger
process by using a posix queue fifo which is non blocking. This means
that kamailio workers would never wait for the "syslog()" call to
return.
- Posix mesage queues implement a configurable queue. But also, the
syslogger process could manage its own queue (by using an array as a
FIFO system) so messages received by the posix queue would be
inserted in the FIFO and extracted from there when they are logged to
syslog.
- In this way, if syslog daemon gets frozen kamailio workers wouldn't
realize of it. Some logs would be lost in case the FIFO gets full but
this is not so important as getting Kamailio non processing SIP
messages :)
Opinnions? Do you consider it feasible?
Other people are better judges of the architecture, but I do agree with the results.
We can accept syslog messages getting lost, as long as Kamailio keeps
running the SIP handling processes.
/O
Being a
multiprocess blocking design it would be a bit difficult such
solution. Perhaps the "ping syslog" mechanism I suggested in my
initial mail :)
I thought it wasn't easy... But still, we need some sort of solution
since this can affect a lot of systems.
11:57 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
El Wed, 28 Jul 2010 22:27:26 +0200
"Olle E. Johansson" <oej(a)edvina.net> escribió:
28 jul 2010 kl. 22.18 skrev Iñaki Baz Castillo:
I do not know from the programmer point of view if this approach is feasible.
But kamailio is never the only process running in a system. Other processes as
cron, a mta, ssh server (at least) run in the same machine. If syslog is
blocked, you might get a frozen system anyways. Almost every service relies on
syslog, which makes this solution incomplete.
I think that the solution to this problem is in syslog's side. It's a critical
service in any system and this solution would just mask the problem.
2010/7/28 Olle E. Johansson
<oej(a)edvina.net>et>:
Let me suggest this proposal:
- Having a dedicated kamailio process to act as syslogger.
- Other kamailio processes send logging messages to such syslogger
process by using a posix queue fifo which is non blocking. This means
that kamailio workers would never wait for the "syslog()" call to
return.
- Posix mesage queues implement a configurable queue. But also, the
syslogger process could manage its own queue (by using an array as a
FIFO system) so messages received by the posix queue would be
inserted in the FIFO and extracted from there when they are logged to
syslog.
- In this way, if syslog daemon gets frozen kamailio workers wouldn't
realize of it. Some logs would be lost in case the FIFO gets full but
this is not so important as getting Kamailio non processing SIP
messages :)
Opinnions? Do you consider it feasible?
Other people are better judges of the architecture, but I do agree with the
results. We can accept syslog messages getting lost, as long as Kamailio keeps
running the SIP handling processes.
Being a
multiprocess blocking design it would be a bit difficult such
solution. Perhaps the "ping syslog" mechanism I suggested in my
initial mail :)
I thought it wasn't easy... But still, we need some sort of solution
since this can affect a lot of systems.
29 Jul
29 Jul
12:08 a.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
2010/7/28 Jon Bonilla <manwe(a)aholab.ehu.es>es>:
I do not know from the programmer point of view if
this approach is feasible.
I've coded a very similar solution for a personal project and works
really well under scenarios with high traffic so I consider it
feasible, I just wonder if it's feasible from the current Kamailio
design point of view.
But kamailio is never the only process running in a
system. Other processes as
cron, a mta, ssh server (at least) run in the same machine. If syslog is
blocked, you might get a frozen system anyways. Almost every service relies on
syslog, which makes this solution incomplete.
Sure, but anyway I don't care ssh, a mta (never running in my kamailio
servers!) or cron (just to rotate logs, no more). If kamailio remains
working that's what I need :)
I think that the solution to this problem is in
syslog's side. It's a critical
service in any system and this solution would just mask the problem.
Don't think in my suggestion just from the point of view of
"reliability" but also think in "efficience":
Currently a kamailio worker must wait for the syslog() call to return
before continuing processing the SIP message (blocking design). Using
a posix queue the worker sends the log to it which is not a blocking
call. Just the kamailio syslogger process should have to deal with
syslog daemon.
Regards.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
8:59 a.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
El Thu, 29 Jul 2010 00:08:54 +0200
Iñaki Baz Castillo <ibc(a)aliax.net> escribió:
What your're suggesting here is having queues in kamailio instead of having
them in syslog. You're trying to fix a syslog problem from kamailio side.
If syslog block because it's mesg buffer is full, kamailio will do what syslog
should do. This solution only works for kamailio, and you're in risk of getting
a frozen system anyways, no warranty of having a working kamailio.
Example: You have a cronjob every 5 minutes. This cronjob cannot finish because
of the unresponsive syslog. You'll get a new cron process every 5 minutes until
you no more processes can be called.
But kamailio is never the only process running in
a system. Other processes
as cron, a mta, ssh server (at least) run in the same machine. If syslog is
blocked, you might get a frozen system anyways. Almost every service relies
on syslog, which makes this solution incomplete.
Sure, but anyway I don't care ssh, a mta (never running in my kamailio
servers!) or cron (just to rotate logs, no more). If kamailio remains
working that's what I need :)
Don't think in my suggestion just from the point of view of
"reliability" but also think in "efficience":
Ok. This is a different point of view. That "efficience" word should now
trigger an "Andrei respawn" :)
4:50 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
On Wednesday 28 July 2010, Iñaki Baz Castillo wrote:
Let me suggest this proposal:
[..]
Hi Iñaki,
in fact kamailio have already such a solution since 1.5.0:
- non-blocking logging
* support for non-blocking log writes to prevent blocking of the server in
certain error situations
* can be enabled by setting the SYSLOG_ASYNC define in the Makefile.defs,
the default is the old implementation
We implemented it sometimes in the past because of a somewhat similar issue.
There is maybe still one bug left (need to dig for the report..), but in
general it should work fine. I'm not sure if we ported this to sr, but should
be not that hard.
Cheers,
Henning
Being a multiprocess blocking design it would be a bit
difficult such
solution. Perhaps the "ping syslog" mechanism I suggested in my
initial mail :)
I thought it wasn't easy... But still, we need some sort of solution
since this can affect a lot of systems.
5:32 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
2010/7/29 Henning Westerholt <henning.westerholt(a)1und1.de>de>:
Hi Iñaki,
in fact kamailio have already such a solution since 1.5.0:
- non-blocking logging
* support for non-blocking log writes to prevent blocking of the server in
certain error situations
* can be enabled by setting the SYSLOG_ASYNC define in the Makefile.defs,
the default is the old implementation
We implemented it sometimes in the past because of a somewhat similar issue.
There is maybe still one bug left (need to dig for the report..), but in
general it should work fine. I'm not sure if we ported this to sr, but should
be not that hard.
Ops, I didn't know it!
Do you use it in production?
PS: The problem for me is that changes into Makefile.defs are not
enabled when doing "make deb" :(
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
5:41 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
On Thursday 29 July 2010, Iñaki Baz Castillo wrote:
Hi Iñaki,
we planned to use it during some time were we needed some extensive logging on
balancer class systems. But in the end we don't needed it, and don't use it so
far. But the implementation should be straightforward, its a bit easier than
you suggested - it just throw away log lines if some internal buffer is
filled.
Cheers,
Henning
in fact
kamailio have already such a solution since 1.5.0:
- non-blocking logging
* support for non-blocking log writes to prevent blocking of the server
in certain error situations
* can be enabled by setting the SYSLOG_ASYNC define in the
Makefile.defs, the default is the old implementation
We implemented it sometimes in the past because of a somewhat similar
issue. There is maybe still one bug left (need to dig for the report..),
but in general it should work fine. I'm not sure if we ported this to sr,
but should be not that hard.
Ops, I didn't know it!
Do you use it in production?
6:38 p.m.
New subject: kamailio gets frozen when rsyslog-mysql cannot send the SQL query
2010/7/29 Henning Westerholt <henning.westerholt(a)1und1.de>de>:
Ok, thanks a lot.
--
Iñaki Baz Castillo
<ibc(a)aliax.net>
Ops, I
didn't know it!
Do you use it in production?
Hi Iñaki,
we planned to use it during some time were we needed some extensive logging on
balancer class systems. But in the end we don't needed it, and don't use it so
far. But the implementation should be straightforward, its a bit easier than
you suggested - it just throw away log lines if some internal buffer is
filled.
5031
days inactive
5032
days old
15 comments
4 participants
participants (4)
-
Henning Westerholt -
Iñaki Baz Castillo -
Jon Bonilla -
Olle E. Johansson