[Freeipa-devel] slow response

[Rich Megginson]

On 08/02/2012 11:29 AM, Stephen Ingram wrote:
> On Thu, Aug 2, 2012 at 10:23 AM, Simo Sorce<simo at redhat.com>  wrote:
>> On Thu, 2012-08-02 at 10:17 -0700, Stephen Ingram wrote:
>>> On Wed, Aug 1, 2012 at 7:35 AM, Simo Sorce<simo at redhat.com>  wrote:
>>>> On Tue, 2012-07-31 at 08:49 -0700, Stephen Ingram wrote:
>>>>> On Tue, Jul 31, 2012 at 1:39 AM, Petr Spacek<pspacek at redhat.com>  wrote:
>>>>>> On 07/31/2012 12:27 AM, John Dennis wrote:
>>>>>>>
>>>>>>> What is taking so long with session bookkeeping? I don't know yet. I would
>>>>>>> need more timing instrumentation. I will say when I looked at the
>>>>>>> python-krb5
>>>>>>> code (which we use to populate the ccache from the session and read back
>>>>>>> to
>>>>>>> store in the session) seemed to be remarkably inefficient. We also elected
>>>>>>> to
>>>>>>> use file based ccache rather than in-memory ccache (that means there is a
>>>>>>> bit
>>>>>>> of file-IO occurring).
>>>>>>
>>>>>> A note regarding python-krbV:
>>>>>> I used python-krbV extensively in my thesis for KDC stress test. Python-krbV
>>>>>> can obtain several thousands of TGTs per second (even with ccache in a
>>>>>> file). AFAIK VFS calls are not done synchronously. But others parts of
>>>>>> python-krbV were left uncovered, so it can contain some surprises.
>>>>>>
>>>>>> === Wild speculation follows ===
>>>>>> 1.5 second is incredibly long time, it sounds like some kind of timeout.
>>>>>> Krb5 libs have usual timeout = 1 second per request.
>>>>>>
>>>>>> Are all KDCs in /etc/krb5.conf alive and reachable?
>>>>> In this case, as I'm referring to the extreme slowness of the Web UI,
>>>>> the KDC is on the same system (the ipa server) that is making the
>>>>> request, correct?
>>>>>
>>>>>> Is SSSD running on problematic server?
>>>>> Yes. Again, I'm guessing the problematic server is the IPA server itself.
>>>>>
>>>>>> Is proper KDC selected by SSSD KDC auto-locator plugin?
>>>>>> (See /var/lib/sss/pubconf/)
>>>>> Yes, I checked that file and it is the IP address of the IPA server on
>>>>> the same server. Perhaps should this be 127.0.0.1 instead?
>>>>>
>>>>> I also have checked the resolv.conf file, and indeed the IP points to
>>>>> the IPA server itself (same machine) as expected. Both forward and
>>>>> reverse DNS work. I'm not really sure what else could be setup
>>>>> incorrectly to cause any KDC slowness.
>>>>>
>>>>> Due to the extreme UI slowness issue, I have not created any replicas
>>>>> so this system is it. I'm not so sure I would be able to see the 1.5 s
>>>>> delay if it weren't compounded by the overall slowness of the Web UI,
>>>>> however, the KDC seems to perform well for other systems in the realm.
>>>>> I'm certainly not taxing it with a huge load, but tickets seem to be
>>>>> issued without delay.
>>>> Stephen,
>>>> another user sent me a wireshark trace for a similar performance issue.
>>>> So far I see a pause when doing the first leg of a SASL authentication.
>>>> This may well explain also your issue.
>>>>
>>>> Can you test connecting to the ldap server using ldapsearch -Y GSSAPI
>>>> (you need a kerberos ticket) and telling me if you experience any
>>>> delay ?
>>>> If you could run a bunch of searches in a loop and take a wireshark
>>>> trace that may help analyzing the timings and seeing if there is a
>>>> correlation.
>>> I've done this. It looks like this delay has been uncovered already
>>> though? I can still send you the dump privately if you think it would
>>> help.
>> I think we reproduced it, can you confirm you are also running on RHEL ?
>> So far it seem the only platfrom we can reproduce is RHEL 6.3
>
> Yes, I'm running RHEL 6.3. I just ran the command in the BZ and it
> takes 1.542s for me. What are Z-stream packages?

They are packages delivered between minor RHEL releases e.g. between 
RHEL 6.3 and RHEL 6.4 - the 389-ds-base package released with RHEL 6.3 
was 389-ds-base-1.2.10.2-15.el6 - since RHEL 6.3, we released some 
bugfix packages, and the latest is now 389-ds-base-1.2.10.2-20.el6_3 - 
note the "_3" at the end - this means it is a bugfix release for RHEL 
6.3 - "Z-stream" is just Red Hat terminology for a package released 
between minor RHEL releases - the "Z" stands for the "Z" in the 
versioning scheme "X.Y.Z"


> Is this new for
> 389ds?
>
> Steve