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Hi Franck,

although it's a different topic than your original question I wanted  
to comment on the volume creation time (maybe a new thread would make  
sense). What is your storage back end? If it is ceph, are your images  
in raw format? Otherwise cinder has to download the image from glance  
(to /var/lib/cinder/conversion) and convert it, then upload it back to  
ceph. It's similar with nova, nova stores base images in  
/var/lib/nova/instances/_base to prevent the compute nodes from  
downloading it every time. This may save some time for the download,  
but the upload has to happen anyway. And if you don't use shared  
storage for nova (e.g. for live-migration) you may encounter that some  
compute nodes are quicker creating an instance because they only have  
to upload, others will first have to download, convert and then upload  
it.

You would see the conversion in the logs of cinder:

INFO cinder.image.image_utils  
[req-f2062570-4006-464b-a1f5-d0d5ac34670d  
d71f59600f1c40c394022738d4864915 31b9b4900a4d4bdaabaf263d0b4021be - -  
-] Converted 2252.00 MB image at 757.52 MB/s

Hope this helps.

Eugen


Zitat von Franck VEDEL <franck.vedel at univ-grenoble-alpes.fr>:

> Sunday morning: my openstack works…. OUF.
> the "kolla-ansible -i multimode mariadb_recovery"  command (which is  
> magic anyway) fixed the problem and then the mariadb and nova  
> containers started.
> Once solved the problems between my serv3 and the iscsi bay, restart  
> the container glance, everything seems to work.
>
>> 4 minutes to create a 20GB empty volume seems too long to me. For  
>> an actual 20GB image, it's going to depend on the speed of the  
>> backing storage tech.
> 4 minutes is for a volume from an image. I will see this problem  
> next summer , I will retry to change the MTU value.
>
> Thanks a lot, really
>
>
> Franck
>
>> Le 5 févr. 2022 à 17:08, Laurent Dumont <laurentfdumont at gmail.com> a écrit :
>>
>> Any chance to revert back switches + server? That would indicate  
>> that MTU was the issue.
>> Dont ping the iscsi bay, ping between the controllers in Openstack,  
>> they are the ones running mariadb/galera.
>> Since the icmp packets are small, it might not trigger the MTU  
>> issues. Can you try something like "ping -s 8972 -M do -c 4  
>> $mariadb_host_2" from $ mariadb_host_1?
>> What is your network setup on the servers? Two ports in a bond? Did  
>> you change both physical interface MTU + bond interface itself?
>>
>> 4 minutes to create a 20GB empty volume seems too long to me. For  
>> an actual 20GB image, it's going to depend on the speed of the  
>> backing storage tech.
>>
>> On Sat, Feb 5, 2022 at 1:51 AM Franck VEDEL  
>> <franck.vedel at univ-grenoble-alpes.fr  
>> <mailto:franck.vedel at univ-grenoble-alpes.fr>> wrote:
>> Thanks for your help.
>>
>>
>>> What was the starting value for MTU?
>> 1500
>>> What was the starting value changed to for MTU?
>> 9000
>>> Can ping between all your controllers?
>> yes, all container starts except nova-conductor, nova-scheduler, maraidb
>>
>>
>>> Do you just have two controllers running mariadb?
>> yes
>>> How did you change MTU?
>>
>> On the 3 servers:
>> nmcli connection modify team0-port1 802-3-ethernet.mtu 9000
>> nmcli connection modify team1-port2 802-3-ethernet.mtu 9000
>> nmcli connection modify type team0 team.runner lack ethernet.mtu 9000
>> nmcli con down team0
>> nmcli con down team1
>>
>>
>>> Was the change reverted at the network level as well (switches  
>>> need to be configured higher or at the same MTU value then the  
>>> servers)
>> I didn’t change Mtu on network (switches) , but ping -s 10.0.5.117  
>> (iscsi bay) was working from serv3.
>>
>> I changed the value of the mtu because the creation of the volumes  
>> takes a lot of time I find (4 minutes for 20G, which is too long  
>> for what I want to do, the patience of the students decreases with  
>> the years)
>>
>> Franck
>>
>>> Le 4 févr. 2022 à 23:12, Laurent Dumont <laurentfdumont at gmail.com  
>>> <mailto:laurentfdumont at gmail.com>> a écrit :
>>>
>>> What was the starting value for MTU?
>>> What was the starting value changed to for MTU?
>>> Can ping between all your controllers?
>>> Do you just have two controllers running mariadb?
>>> How did you change MTU?
>>> Was the change reverted at the network level as well (switches  
>>> need to be configured higher or at the same MTU value then the  
>>> servers)
>>> 4567 seems to be the port for galera (clustering for mariadb) <>
>>> On Fri, Feb 4, 2022 at 11:52 AM Franck VEDEL  
>>> <franck.vedel at univ-grenoble-alpes.fr  
>>> <mailto:franck.vedel at univ-grenoble-alpes.fr>> wrote:
>>> Hello,
>>> I am in an emergency situation, quite catastrophic situation  
>>> because I do not know what to do.
>>>
>>> I have an Openstack cluster with 3 servers (serv1, serv2, serv3).  
>>> He was doing so well…
>>>
>>>
>>> A network admin came to me and told me to change an MTU on the  
>>> cards. I knew it shouldn't be done...I shouldn't have done it.
>>> I did it.
>>> Of course, it didn't work as expected. I went back to my starting  
>>> configuration and there I have a big problem with mariadb which is  
>>> set up on serv1 and serv2.
>>>
>>> Here are my errors:
>>>
>>>
>>> 2022-02-04 17:40:36 0 [ERROR] WSREP: failed to open gcomm backend  
>>> connection: 110: failed to reach primary view: 110 (Connection  
>>> timed out)
>>> 	 at gcomm/src/pc.cpp:connect():160
>>> 2022-02-04 17:40:36 0 [ERROR] WSREP:  
>>> gcs/src/gcs_core.cpp:gcs_core_open():209: Failed to open backend  
>>> connection: -110 (Connection timed out)
>>> 2022-02-04 17:40:36 0 [ERROR] WSREP:  
>>> gcs/src/gcs.cpp:gcs_open():1475: Failed to open channel  
>>> 'openstack' at 'gcomm://10.0.5.109:4567,10.0.5.110:4567': <> -110  
>>> (Connection timed out)
>>> 2022-02-04 17:40:36 0 [ERROR] WSREP: gcs connect failed:  
>>> Connection timed out
>>> 2022-02-04 17:40:36 0 [ERROR] WSREP:  
>>> wsrep::connect(gcomm://10.0.5.109:4567,10.0.5.110:4567 <>) failed: 7
>>> 2022-02-04 17:40:36 0 [ERROR] Aborting
>>>
>>>
>>>
>>>
>>> I do not know what to do. My installation is done with  
>>> kolla-ansible, mariadb docker restarts every 30 seconds.
>>>
>>> Can the "kolla-ansible reconfigure mariadb" command be a solution?
>>> Could the command "kolla-ansible mariadb recovery" be a solution?
>>>
>>> Thanks in advance if you can help me.
>>>
>>>
>>>
>>> Franck
>>>
>>>
>>