[Swift] [kolla] Swift issues in one cluster

Albert Braden ozzzo at yahoo.com
Fri Jun 24 15:24:34 UTC 2022

 Reading in [1] I see this:

"Having another look at that issue, it sounds like slow client shouldn't be handled by OpenStack services but rather with a load balancer, especially if the service is Internet facing"

I don't understand what is being recommended here. We have 60 Swift servers, and customer traffic goes directly to those servers. It seems like a load-balancer would be a performance-reducing bottleneck. Our clusters are not internet-facing, and I haven't seen internet-facing Swift clusters at any of my employers. What is the solution for this problem? We have worked around it by getting our customer to stop using his Java app to download large files for now, but we would like to find a long-term solution. Is there any hope of getting this bug fixed?
     On Thursday, June 23, 2022, 12:49:29 PM EDT, Albert Braden <ozzzo at yahoo.com> wrote:  
  We're running 2.23.3 but it appears that we are experiencing the bug (1). We tracked the problem down to a client who recently started using a java library to read large files from Swift. When he moves his activity to the other QA cluster, the problem follows. Am I guessing correctly that the bug was never fixed, and that (2) fixes a different problem?
     On Thursday, June 23, 2022, 10:43:44 AM EDT, Clay Gerrard <clay.gerrard at gmail.com> wrote:  
 https://review.opendev.org/c/openstack/swift/+/575254 has been included in every released swift tag since 2.21.0

I believe Train included a swift version of at least 2.22 https://releases.openstack.org/train/#swift
Nvidia doesn't use haproxy in front of our swift proxies, and we don't see BlockingIOError in tracebacks - the traceback might go away if you upgrade to the latest swift (2.29) and/or eventlet and/or python 3.8ish
On Thu, Jun 23, 2022 at 8:49 AM Albert Braden <ozzzo at yahoo.com> wrote:

 Can anyone help with this Swift issue? It looks like we are being hit with this bug (1) but this bug doesn't seem to mention where/whether it was ever fixed. This (2) appears to be a fix, and it appears to have been merged, but it doesn't mention the bug, and it's not obvious to me what version it affects. Is anyone else encountering this problem? It appears that customers in this one cluster may be doing something to cause it; we're still trying to track down specifically what they are doing, that they aren't doing in the other clusters.

We are running kolla-ansible Train on RHEL7.

1. https://bugs.launchpad.net/swift/+bug/1572719
2. https://opendev.org/openstack/swift/commit/0e81ffd1e1481a73146fce17f61f2ab9e01eb684
     On Wednesday, June 22, 2022, 05:10:10 PM EDT, Albert Braden <ozzzo at yahoo.com> wrote:  
  Is this bug fixed in Train?

     On Tuesday, June 21, 2022, 09:26:47 AM EDT, Albert Braden <ozzzo at yahoo.com> wrote:  
  All of our endpoints are https:

| ID | Region | Service Name | Service Type | Enabled | Interface | URL |
| <ID> | <region> | keystone | identity | True | internal | https://api-int.<region>.<domain>:5000 |
| <ID> | <region>| swift | object-store | True | public | https://swift. <region>.<domain>:8080/v1/AUTH_%(tenant_id)s |
| <ID> | <region>| swift | object-store | True | internal | https://swift.<region>.<domain>:8080/v1/AUTH_%(tenant_id)s |
| <ID> | <region>| keystone | identity | True | admin | https://api-int. <region>.<domain>:35357 |
| <ID> | <region>| keystone | identity | True | public | https://api-ext. <region>.<domain>:5000 |
| <ID> | <region>| swift | object-store | True | admin | https://swift. <region>.<domain>:8080/v1 |

I don't think this is causing the issue; all of our clusters are setup the same. We did think it was load at first, and got the 2 heaviest users to stop what they were doing, but that didn't make a difference. Our other QA cluster has similar load and identical hardware. When I look at the network graphs, I see traffic spiking up to 1G, but these are 25G interfaces, and none of the resources on the boxes are exhausted. CPU is 97% idle; memory is 30% used, disk is not full. It doesn't look like the problem is load-related. We see the haproxy connections stacking up even when load is low. What else could be causing this?
     On Friday, June 17, 2022, 11:12:36 PM EDT, Pete Zaitcev <zaitcev at redhat.com> wrote:  
 On Fri, 17 Jun 2022 17:33:27 +0000 (UTC)
Albert Braden <ozzzo at yahoo.com> wrote:

> $ openstack container list
> Unable to establish connection to https://swift.<region>.<domain>:8080/v1/AUTH_<project>: ('Connection aborted.', ConnectionResetError(104, 'Connection reset by peer')

Right away I have a question: why in the world are you connecting
to 8080 with HTTPS?

> (from Splunk):
> Payload: swift-proxy-server: STDERR: File "/usr/lib64/python3.6/socket.py", line 604, in write#012 return self._sock.send(b)
> Payload: swift-proxy-server: STDERR: BlockingIOError
> Payload: swift-proxy-server: STDERR: os.read(self.rfd, 1)
> Payload: swift-proxy-server: STDERR: File "/usr/lib/python3.6/site-packages/eventlet/wsgi.py", line 818, in process_request#012 proto.__init__(conn_state, self)

This looks quite fishy to me, because the os.read is in swift/common/utils.py
and it's responsible for the mutex.

> When we look at network connections, we see haproxy stacking up (many lines of this):
> # netstat -ntup | sort -b -k2 -n -r | head -n +100
> tcp  5976932      0          ESTABLISHED 13045/haproxy      
> tcp  5976446      0          ESTABLISHED 13045/haproxy      
> tcp  5973217      0          ESTABLISHED 13045/haproxy      
> tcp  5973120      0          ESTABLISHED 13045/haproxy      
> tcp  5971968      0          ESTABLISHED 13045/haproxy      
>  ...
> If we restart the swift_haproxy and swift_proxy_server containers then the problem goes away, and comes back over a few minutes. Where should we be looking for the root cause of this issue?

Indeed if so many requests are established, you're in trouble.
The best fix, I think, is to find the customer who's doing it and punish them.
Otherwise, quotas and the ratelimiting middleware are your friends.

There's also a possibility that your cluster is underperforming, although
usually that results in 500 results first. But then again, at times
users would "compensate" for issues by just launching way more requests,
in effect DoS-ing the cluster even worse.

-- Pete


Clay Gerrard210 788 9431
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