[ovs-dev] [PATCH v2] bridge: don't bring up internal ports by default.

[Gurucharan Shetty]

On Mon, Mar 31, 2014 at 1:19 PM, Ben Pfaff <blp at nicira.com> wrote:
> On Tue, Mar 25, 2014 at 02:50:17PM -0300, Flavio Leitner wrote:
>> It should be an administrator task to bring up devices as they
>> are configured properly.
>>
>> Currently, Fedora is deleting the bridges when the interface is
>> brought down. Therefore, there is no bridge on the next boot and
>> the initscripts can apply the networking configuration properly
>> for a new bridge.
>>
>> However, if the system didn't execute ifdown for some reason, the
>> bridge is left in the ovsdb and since internal ports are brought
>> up by default, there is no way for initscripts to known if the
>> adminitrator has configured it or not already.
>>
>> This patch partially reverts the commit
>> bef071a5fdf8e2dd87677b04b3cf7a8f5094edcb
>>
>> Signed-off-by: Flavio Leitner <fbl at redhat.com>
>
> I think you're right, that this is correct, but let's put the NEWS
> item at the top and give a little more explanation, something like
> this:
>
>    - Internal ports are no longer brought up by default, because it should be
>      an administrator task to bring up devices as they are configured properly.
>
> This is almost certain to break some people's setups, but I guess it's
> better than what we do now.
In most of the setups using Open vSwitch on hypervisors, we have a
integration bridge(br-int) with VM virtual interfaces attached to it
through a third utility (e.g., libvirt).
So far, adding a bridge to a ifcfg-* script or interfaces (on debian)
script was optional. Assuming there is a kernel crash or a reboot,
br-int would be automatically be UP and VMs would get started
automatically and traffic would flow after an outage. Now, that won't
be the case anymore. One is forced to add these bridges to some sort
of startup network configuration scripts. Assuming, we do ask users to
add some way to auto-start their integration bridge, then these
bridges are deleted and re-created. So any ports added will have to be
added back.

Also, if someone programmatically creates bridges using OVSDB, he is
now forced to add those bridges to some startup script. I don't think
it is feasible.

I feel that a default UP has less negative consequences than a default down.

Thanks,
Guru

>
> Please give a title when referring to a commit in a log message, e.g.:
>
>      This patch partially reverts the commit
>     bef071a5fdf8e2dd87677b04b3cf7a8f5094edcb (bridge: Always "up" internal
>     devices.).
>
> Finally, I would have just fixed all of the above and pushed it,
> except that it also breaks half a dozen tests in the testsuite.
> Please fix those and submit a v3.
>
> Thanks,
>
> Ben.
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