Hi Joe,

I can share some details on how murano is configured as part of the
default Mirantis OpenStack configuration and try to explain why it's
done in that way as it's done, I hope it helps you in your case.

As part of Mirantis OpenStack second instance of the RabbitMQ is
getting deployed specially for the murano, but it's configuration is
different than for the RabbitMQ instance used by the other OpenStack
components.

Why to use separate instance of the RabbitMQ?
     1. Prevent possibility to get access to the RabbitMQ supporting
whole cloud infrastructure by limiting access on the networking level
rather than rely on authentication/authorization
     2. Prevent possibility of DDoS by limiting access on the
networking level to the infrastructure RabbitMQ

Given that second RabbitMQ instance is used only for the murano-agent
<-> murano-engine communications and murano-agent is running on the
VMs we had to make couple of changes in the deployment of the RabbitMQ
(bellow I am referencing RabbitMQ as RabbitMQ instance used by Murano
for m-agent <-> m-engine communications):

1. RabbitMQ is not clustered, just separate instance running on each
controller node
2. RabbitMQ is exposed on the Public VIP where all OpenStack APIs are exposed
3. It's has different port number than default
4. HAProxy is used, RabbitMQ is hidden behind it and HAProxy is always
pointing to the RabbitMQ on the current primary controller

Note: How murano-agent is working? Murano-engine creates queue with
uniq name and put configuration tasks to that queue which are later
getting picked up by murano-agent when VM is booted and murano-agent
is configured to use created queue through cloud-init.

#1 Clustering

* Given that per 1 app deployment from we create 1-N VMs and send 1-M
configuration tasks, where in most of the cases N and M are less than
3.
* Even if app deployment will be failed due to cluster failover it's
can be always re-deployed by the user.
* Controller-node failover most probably will lead to limited
accessibility of the Heat, Nova & Neutron API and application
deployment will fail regardless of the not executing configuration
task on the VM.

#2 Exposure on the Public VIP

One of the reasons behind choosing RabbitMQ as transport for
murano-agent communications was connectivity from the VM - it's much
easier to implement connectivity *from* the VM than *to* VM.

But even in the case when you are connecting to the broker from the VM
you should have connectivity and public interface where all other
OpenStack APIs are exposed is most natural way to do that.

#3 Different from the default port number

Just to avoid confusion from the RabbitMQ used for the infrastructure,
even given that they are on the different networks.

#4 HAProxy

In case of the default Mirantis OpenStack configuration is used mostly
to support non-clustered RabbitMQ setup and exposure on the Public
VIP, but also helpful in case of more complicated setups.

P.S. I hope my answers helped, let me know if I can cover something in
more details.
-- 
Serg Melikyan, Development Manager at Mirantis, Inc.
http://mirantis.com | smelik...@mirantis.com

_______________________________________________
OpenStack-operators mailing list
OpenStack-operators@lists.openstack.org
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators

Reply via email to