Turns out we had configured our services to connect to mcrouter via haproxy, but we didn't have a stanza for mcrouter in our haproxy config, and that was breaking caching.
On Thursday, April 4, 2024 at 03:45:27 AM EDT, Eugen Block <eblock@nde.ag> wrote:


I know absolutely nothing about mcrouter, unfortunately. I also 
remember that we didn't really have much to go on with memcached, it's 
been a couple of years since we last tweaked it. I'll need to ask a 
colleague if he remembers the details how we pinpointed it to 
memcached. I'll get back to you if I get more details.

Zitat von Albert Braden <ozzzo@yahoo.com>:

> That's plausible; we did have some trouble with memcached/mcrouter 
> after the rebuild and we had to tweak our mcrouter config, but I'm 
> having trouble getting good logs. I set designate_logging_debug: 
> "True" and did a full deploy but I don't see any logs for memcached 
> and mcrouter doesn't log anything interesting.
>      On Tuesday, April 2, 2024 at 03:50:53 PM EDT, Eugen Block 
> <eblock@nde.ag> wrote:
>
>  Hm, we’ve seen something similar in the past when our memcached config 
> was not correct, although I’m not sure if keystone was the culprit or 
> if it was a different service. Anyway, I would probably start to 
> compare memcached configs.
>
> Zitat von "Braden, Albert" <abraden@verisign.com>:
>
>> The timing result is 1.6 seconds (vs 0.2 on a non-rebuilt region), 
>> but the elapsed time is 2.7 seconds (vs 1.2):
>>
>> Rebuilt region:
>>
>> $ time openstack user show --timing user
>> +---------------------+------------------------------------------------------------------+
>> | Field              | Value                                       
>>                     |
>> +---------------------+------------------------------------------------------------------+
>> | domain_id          | <DID>                                |
>> | email              | user@ourdomain.com                           
>>                   |
>> | enabled            | True                                         
>>                     |
>> | id                  | <ID> |
>> | name                | user                                         
>>                   |
>> | options            | {}                                           
>>                     |
>> | password_expires_at | None                                         
>>                     |
>> +---------------------+------------------------------------------------------------------+
>>
>> +------------------------------------------------------------------------------------------------------------------+--------------------+
>> | URL                                                               
>>                                               |            Seconds |
>> +------------------------------------------------------------------------------------------------------------------+--------------------+
>> | GET https://api-ext.region.ourdomain.com:5000/v3                   
>>                                                       |           
>> 0.030608 |
>> | POST https://api-ext.region.ourdomain.com:5000/v3/auth/tokens     
>>                                                       |           
>> 0.550521 |
>> | GET https://api-ext.region.ourdomain.com:5000/                     
>>                                                       |           
>> 0.006306 |
>> | GET https://api-ext.region.ourdomain.com:5000/v3/auth/tokens       
>>                                                       |           
>> 0.608377 |
>> | GET https://api-ext.region.ourdomain.com:5000/v3/users/<ID> |     
>>       0.458892 |
>> | Total                                                             
>>                                               | 1.6547040000000002 |
>> +------------------------------------------------------------------------------------------------------------------+--------------------+
>>
>> real    0m2.733s
>> user    0m0.982s
>> sys    0m0.105s
>>
>> Not rebuilt:
>>
>> $ time openstack user show --timing user
>> +---------------------+------------------------------------------------------------------+
>> | Field              | Value                                       
>>                     |
>> +---------------------+------------------------------------------------------------------+
>> | domain_id          | <DID>                                |
>> | email              | user@ourdomain.com                           
>>                   |
>> | enabled            | True                                         
>>                     |
>> | id                  | <ID> |
>> | name                | user                                         
>>                   |
>> | options            | {}                                           
>>                     |
>> | password_expires_at | None                                         
>>                     |
>> +---------------------+------------------------------------------------------------------+
>>
>> +------------------------------------------------------------------------------------------------------------------+----------+
>> | URL                                                               
>>                                               |  Seconds |
>> +------------------------------------------------------------------------------------------------------------------+----------+
>> | GET https://api-ext.oldregion.ourdomain.com:5000/v3               
>>                                                         | 0.026787 |
>> | POST https://api-ext.oldregion.ourdomain.com:5000/v3/auth/tokens   
>>                                                         | 0.042511 |
>> | GET https://api-ext.oldregion.ourdomain.com:5000/                 
>>                                                         |  0.00767 |
>> | GET https://api-ext.oldregion.ourdomain.com:5000/v3/auth/tokens   
>>                                                         | 0.049546 |
>> | GET https://api-ext.oldregion.ourdomain.com:5000/v3/users/<ID> | 
>> 0.044296 |
>> | Total                                                             
>>                                               |  0.17081 |
>> +------------------------------------------------------------------------------------------------------------------+----------+
>>
>> real    0m1.176s
>> user    0m0.892s
>> sys    0m0.118s
>>
>> -----Original Message-----
>> From: Eugen Block <eblock@nde.ag>
>> Sent: Tuesday, April 2, 2024 12:52 PM
>> To: openstack-discuss@lists.openstack.org
>> Subject: [EXTERNAL] Re: [kolla] [Wallaby] Openstack operations 2x 
>> slower after rebuilding from RHEL8/Train to RHEL9/Wallaby
>>
>> Caution: This email originated from outside the organization. Do not 
>> click links or open attachments unless you recognize the sender and 
>> know the content is safe.
>>
>> Hi, could you please share the details of (or any other command that 
>> takes longer than usual):
>>
>> openstack user show --timing
>>
>> Thanks,
>> Eugen
>>
>> Zitat von Albert Braden <ozzzo@yahoo.com>:
>>
>>> After rebuilding a couple of our clusters, moving from Train on
>>> RHEL8 to Wallaby on RHEL9, we see all openstack operations taking 2x
>>> longer. Even simple database reads such as "openstack user show"
>>> average 1.5 seconds on old regions and 3 seconds on rebuilt regions.
>>> I enabled debug and poked around in the logs but nothing is jumping
>>> out at me. I was thinking maybe mariadb needed to be tuned differently
>>> from RHEL8->9 but if I log into the mariadb container and query the
>>> database it seems equally fast; I can do 100 simple queries in a
>>> second. Where should I be looking for the source of this delay?