On 11/21/2014 10:59 AM, dbisc...@hrz.uni-kassel.de wrote:
Hi,
On Thu, 20 Nov 2014, thierry bordaz wrote:
On 11/20/2014 12:03 PM, dbisc...@hrz.uni-kassel.de wrote:
On Thu, 20 Nov 2014, thierry bordaz wrote:
Server1 successfully replicated to Server2, but Server2 fails to
replicated to Server1.
The replication Server2->Server1 is done with kerberos
authentication. Server1 receives the replication session,
successfully identify the replication manager, start to receives
replication extop but suddenly closes the connection.
[19/Nov/2014:14:21:39 +0100] conn=2980 fd=78 slot=78 connection from
xxx to yyy
[19/Nov/2014:14:21:39 +0100] conn=2980 op=0 BIND dn="" method=sasl
version=3 mech=GSSAPI
[19/Nov/2014:14:21:39 +0100] conn=2980 op=0 RESULT err=14 tag=97
nentries=0 etime=0, SASL bind in progress
[19/Nov/2014:14:21:39 +0100] conn=2980 op=1 BIND dn="" method=sasl
version=3 mech=GSSAPI
[19/Nov/2014:14:21:39 +0100] conn=2980 op=1 RESULT err=14 tag=97
nentries=0 etime=0, SASL bind in progress
[19/Nov/2014:14:21:39 +0100] conn=2980 op=2 BIND dn="" method=sasl
version=3 mech=GSSAPI
[19/Nov/2014:14:21:39 +0100] conn=2980 op=2 RESULT err=0 tag=97
nentries=0 etime=0 dn="krbprincipalname=xxx"
[19/Nov/2014:14:21:39 +0100] conn=2980 op=3 SRCH base="" scope=0
filter="(objectClass=*)" attrs="supportedControl supportedExtension"
[19/Nov/2014:14:21:39 +0100] conn=2980 op=3 RESULT err=0 tag=101
nentries=1 etime=0
[19/Nov/2014:14:21:39 +0100] conn=2980 op=4 SRCH base="" scope=0
filter="(objectClass=*)" attrs="supportedControl supportedExtension"
[19/Nov/2014:14:21:39 +0100] conn=2980 op=4 RESULT err=0 tag=101
nentries=1 etime=0
[19/Nov/2014:14:21:39 +0100] conn=2980 op=5 EXT
oid="2.16.840.1.113730.3.5.12" name="replication-multimaster-extop"
[19/Nov/2014:14:21:39 +0100] conn=2980 op=5 RESULT err=0 tag=120
nentries=0 etime=0
[19/Nov/2014:14:21:39 +0100] conn=2980 op=6 SRCH base="cn=schema"
scope=0 filter="(objectClass=*)" attrs="nsSchemaCSN"
[19/Nov/2014:14:21:39 +0100] conn=2980 op=6 RESULT err=0 tag=101
nentries=1 etime=0
[19/Nov/2014:14:21:39 +0100] conn=2980 op=-1 fd=78 closed - I/O
function error.
The reason of this closure is logged in server1 error log.
sasl_decode fails to decode a received PDU.
[19/Nov/2014:14:21:39 +0100] - sasl_io_recv failed to decode packet
for connection 2980
I do not know why it fails but I wonder if the received PDU is not
larger than the maximum configured value. The attribute
nsslapd-maxsasliosize is set to 2Mb by default. Would it be
possible to increase its value (5Mb) to see if it has an impact
[...]
I set nsslapd-maxsasliosize to 6164480 on both machines, but the
problem remains.
The sasl-decode fails but the exact returned value is not logged.
With standard version we may need to attach a debugger and then set a
conditional breakpoint in sasl-decode just after conn->oparams.decode
that will fire if result !=0. Now this can change the dynamic and
possibly prevent the problem to occur again. The other option is to
use an instrumented version to log this value.
If I understand the mechanism correctly, Server1 needs to have debug
versions of the relevant packages (probably 389-ds-base and
cyrus-sasl) installed in order to track down the problem.
Unfortunately, my Server1 is in production use - if I break it, my
colleagues will grab forks and torches and be after me. A short
downtime would be ok, though.
Is there something else I could do?
Hello,
Sure I do not want to trigger so much trouble ;-)
I think my email was not clear. To go further we would need to know the
exact reason why sasl_decode fails. I see two options:
* Prepare a debug version, that would report in the error logs the
returned valud of sasl_decode (when it fails). Except downtime to
install the debug version, it has no impact in production.
* Do a debug session (gdb) on Server1. The debug session will install
a breakpoint at a specific place, let the server run, catch the
sasl_decode failure and note the return code, exit from debugger.
When the problem occurs, it happens regularly (each 5 seconds) so we
should not have to wait long.
That means that debugging Server1 should disturb production for 5 to
10 min.
A detailed procedure to do the debug session is required.
thanks
thierry
Mit freundlichen Gruessen/With best regards,
--Daniel.
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