Open Stack

Hi,

> Currently cinder-volume does support Active-Active HA, though not all
> drivers support this configuration.  Besides using a driver that
> supports A/A, a DLM is also required and needs to be configured in
> Cinder, finally the "host" and "backend_host" options must not be
> configured and the "cluster" configuration should be configured instead.

this is interesting information, I was not aware of that. Does the rbd  
driver support A/A? I'm still dealing with some older cloud  
deployments and didn't have the time to look into newer features yet,  
but it would be great! We do currently use the "host" option to let  
haproxy redirect the cinder-volume requests. I'm definitely gonna need  
to look into that. Thanks for pointing that out!

Thanks,
Eugen

Zitat von Gorka Eguileor <geguileo at redhat.com>:

> On 26/08, Eugen Block wrote:
>> Hi,
>>
>> just in addition to the previous response, cinder-volume is a stateful
>> service and there should be only one instance running. We configured it to
>> be bound to the virtual IP controlled by pacemaker, pacemaker also controls
>> all stateless services in our environment although it wouldn't be necessary.
>> But that way we have all resources at one place and don't need to
>> distinguish.
>>
>
> Hi,
>
> Small clarification, cinder-volume is not actually stateful.
>
> It is true that historically the cinder-volume service only supported
> High Availability in Active-Passive mode and required the configuration
> to set the "host" or "backend_host" configuration option to the same
> value in all the different controller nodes, so on failover the newly
> started service would consider existing resources as its own.
>
> Currently cinder-volume does support Active-Active HA, though not all
> drivers support this configuration.  Besides using a driver that
> supports A/A, a DLM is also required and needs to be configured in
> Cinder, finally the "host" and "backend_host" options must not be
> configured and the "cluster" configuration should be configured instead.
>
> Cheers,
> Gorka.
>
>
>>
>> Zitat von Satish Patel <satish.txt at gmail.com>:
>>
>> > Hi,
>> >
>> > 3 nodes requirements come from MySQL galera and RabbitMQ  
>> clustering because
>> > of quorum requirements ( it should be in odd numbers 1, 3, 5 etc..). Rest
>> > of components works without clustering and they live behind HAProxy LB for
>> > load sharing and redundancy.
>> >
>> > Someone else can add more details here if I missed something.
>> >
>> > On Thu, Aug 25, 2022 at 4:05 AM 박경원 <park0kyung0won at dgist.ac.kr> wrote:
>> >
>> > > Hello
>> > >
>> > >
>> > > I have two questions about deploying openstack in high available setup
>> > >
>> > > Specifically, HA setup for controller nodes
>> > >
>> > >
>> > > 1. Are openstack services (being deployed on controller nodes)  
>> stateless?
>> > >
>> > >
>> > > Aside from non-openstack packages(galera/mysql, zeromq, ...) for
>> > > infrastructure, are openstack services stateless?
>> > >
>> > > For example, can I achieve high availability by deploying two nova-api
>> > > services to two separate controller nodes
>> > >
>> > > by load balacing API calls to them through HAproxy?
>> > >
>> > > Is this(load balancer) the way how openstack achieves high availability?
>> > >
>> > >
>> > >
>> > > 2. Why minimum 3 controller nodes for HA?
>> > >
>> > >
>> > > Is this solely due to etcd?
>> > >
>> > >
>> > > Thanks!
>> > >
>>
>>
>>
>>