[openstack-dev] [Openstack] [Quantum] Scalable agents

Dan Wendlandt dan at nicira.com
Mon Jul 23 08:02:40 UTC 2012


On Sun, Jul 22, 2012 at 5:51 AM, Gary Kotton <gkotton at redhat.com> wrote:

> **
>
>
> This is an interesting idea. In addition to the creation we will also need
> the update. I would prefer that the agents would have one topic - that is
> for all updates. When an agent connects to the plugin it will register the
> type of operations that are supported on the specific agent. The agent
> operations can be specific as bit masks.
>
> I have implemented something similar in
> https://review.openstack.org/#/c/9591
>
> This can certainly be improved and optimized. What are your thoughts?
>

Based on your follow-up emails, I think we're now thinking similarly about
this.  Just to be clear though, for updates I was talking about a different
topic for each entity that has its own UUID (e.g., topic
port-update-f01c8dcb-d9c1-4bd6-9101-1924790b4b45)


>
> In addition to this we have a number of issues where the plugin does not
> expose the information via the standard API's - for example the VLAN tag
> (this is being addressed via extensions in the provider networks feature)
>

Agreed.  There are a couple options here: direct DB access (no polling,
just direct fetching), admin API extensions, or custom RPC calls.  Each has
pluses and minuses.  Perhaps my real goal here would be better described as
"if there's an existing plugin agnostic way to doing X, our strong bias
should be to use it until presented with concrete  evidence to the
contrary".   For example, should a DHCP client create a port for the DHCP
server via the standard API, or via a custom API or direct DB access?  My
strong bias would be toward using the standard API.


> 3. Logging. At the moment the agents do not have a decent logging
> mechanism. This makes debugging the RPC code terribly difficult. This was
> scheduled for F-3. I'll be happy to add this if there are no objections.
>

That sounds valuable.


> 4. We need to discuss the notifications that Yong added and how these two
> methods can interact together. More specifically I think that we need to
> address the configuration files.
>

Agreed.  I think we need to decide on this at monday's IRC meeting, so we
can move forward.  Given F-3 deadlines, I'm well aware that I'll have to be
pragmatic here :)


>
> The RPC code requires that the eventlet monkey patch be set. This cause
> havoc when I was using the events from pyudev for new device creation. At
> the moment I have moved the event driven support to polling (if anyone who
> reads this is familiar with the issue or has an idea on how to address it
> any help will be great)
>

Sorry, wish I could help, but I'm probably in the same boat as you on this
one.

I'm going to make sure we have a good chunk of time to discuss this during
the IRC meeting on monday (sorry, I know that's late night for you...).

Dan




>
> Thanks
> Gary
>
>  Dan
>
>
>
>  ~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dan Wendlandt
> Nicira, Inc: www.nicira.com
> twitter: danwendlandt
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Dan Wendlandt
Nicira, Inc: www.nicira.com
twitter: danwendlandt
~~~~~~~~~~~~~~~~~~~~~~~~~~~
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