[ovirt-devel] [proposal] deprecate VDSM ping in favor of ping2 and confirmConnectivity

[Martin Sivak]

What stomp heartbeat? There is no such thing in the Python json rpc client.

Martin

On Tue, Aug 8, 2017 at 1:04 PM, Roy Golan <rgolan at redhat.com> wrote:
> Why isn't the stomp heartbeat enough?
>
> On Tue, 8 Aug 2017 at 13:45 Martin Sivak <msivak at redhat.com> wrote:
>>
>> MOM and hosted engine use the ping verb to verify the connection is
>> still OK. The RPC client did not have any reconnect logic in the past
>> (and I think it still does not..).
>>
>> Martin
>>
>> On Tue, Aug 8, 2017 at 12:01 PM, Roy Golan <rgolan at redhat.com> wrote:
>> > Petr, why do you need the ping verb? what are you after?
>> >
>> > On Tue, 8 Aug 2017 at 11:54 Martin Sivak <msivak at redhat.com> wrote:
>> >>
>> >> > The proposed solution is focused on making sure a command does one
>> >> > thing
>> >> > and
>> >> > not two:
>> >> > A ping that has no side effects and a "watchdog" mechanism to confirm
>> >> > connectivity.
>> >>
>> >> This sounds as exactly the right solution right now.
>> >>
>> >> >>> Still someone could call conirmConnectivity, no?
>> >>
>> >> We do not protect any other endpoints that can cause the host to go
>> >> wild (storage or even setupNetworks). I agree with Edward it is the
>> >> responsibility of the caller to do the right thing. You need to be
>> >> root or have the certificate to talk to VDSM anyway.
>> >>
>> >> Martin
>> >>
>> >> On Tue, Aug 8, 2017 at 8:24 AM, Edward Haas <ehaas at redhat.com> wrote:
>> >> >
>> >> >
>> >> > On Mon, Aug 7, 2017 at 11:06 PM, Nir Soffer <nsoffer at redhat.com>
>> >> > wrote:
>> >> >>
>> >> >> On Mon, Aug 7, 2017 at 5:28 PM Roy Golan <rgolan at redhat.com> wrote:
>> >> >>>
>> >> >>> Still someone could call conirmConnectivity, no? so the state isn't
>> >> >>> guarded from localhost tinkering anyhow. If you really need a
>> >> >>> solution
>> >> >>> you
>> >> >>> can acuire a token for this operation by setupNetworks, and confirm
>> >> >>> connectivity with this token passed back.
>> >> >>>
>> >> >>> I'm not sure about the severity of the problem here, I'll let other
>> >> >>> reply, but I'm against this kind of solution.
>> >> >>>
>> >> >>>
>> >> >>>
>> >> >>> On Mon, 7 Aug 2017 at 15:32 Petr Horacek <phoracek at redhat.com>
>> >> >>> wrote:
>> >> >>>>
>> >> >>>> Hello,
>> >> >>>>
>> >> >>>> current VDSM ping verb has a problem - it confirms network
>> >> >>>> connectivity as a side-effect. After Engine calls setupNetwork it
>> >> >>>> pings VDSM host to confirm that external network connectivity is
>> >> >>>> not
>> >> >>>> broken. This prohibits other users to call ping from localhost
>> >> >>>> since
>> >> >>>> it would confirm connectivity even though networking could be
>> >> >>>> broken.
>> >> >>
>> >> >>
>> >> >> Vdsm can save the client ip setting up the network. Getting a ping
>> >> >> from
>> >> >> this
>> >> >> client can confirm that the connectivity was restored. pings from
>> >> >> other
>> >> >> hosts
>> >> >> can be ignored.
>> >> >>
>> >> >> The client address is available in a thread local variable
>> >> >> (context.client_host)
>> >> >> during all api calls. see vdsm.common.api.context_string() for
>> >> >> example
>> >> >> usage.
>> >> >>
>> >> >> This infrastructure is available in 4.1.
>> >> >
>> >> >
>> >> > The proposed solution is focused on making sure a command does one
>> >> > thing
>> >> > and
>> >> > not two:
>> >> > A ping that has no side effects and a "watchdog" mechanism to confirm
>> >> > connectivity.
>> >> >
>> >> > Does it make sense to confirm connectivity from localhost? In many
>> >> > cases
>> >> > it
>> >> > probably does not,
>> >> > but there may be cases where it does make sense... it is not the
>> >> > functionality to determine what
>> >> > makes sense or not, it is the usage of it who has the responsibility
>> >> > to
>> >> > use
>> >> > it correctly.
>> >> >
>> >> >>
>> >> >> Nir
>> >> >>
>> >> >>>>
>> >> >>>>
>> >> >>>> In order to fix this problem ping should be split to ping2 (which
>> >> >>>> just
>> >> >>>> returns Success with no side-effect) and confirmConnectivity.
>> >> >>>> Change
>> >> >>>> on VDSM side was introduced in [1], we still need to expose new
>> >> >>>> verbs
>> >> >>>> in Engine.
>> >> >>>>
>> >> >>>> Regards,
>> >> >>>> Petr
>> >> >>>>
>> >> >>>> [1] https://gerrit.ovirt.org/#/c/80119/
>> >> >>>> _______________________________________________
>> >> >>>> Devel mailing list
>> >> >>>> Devel at ovirt.org
>> >> >>>> http://lists.ovirt.org/mailman/listinfo/devel
>> >> >>>
>> >> >>> _______________________________________________
>> >> >>> Devel mailing list
>> >> >>> Devel at ovirt.org
>> >> >>> http://lists.ovirt.org/mailman/listinfo/devel
>> >> >>
>> >> >>
>> >> >> _______________________________________________
>> >> >> Devel mailing list
>> >> >> Devel at ovirt.org
>> >> >> http://lists.ovirt.org/mailman/listinfo/devel
>> >> >
>> >> >
>> >> >
>> >> > _______________________________________________
>> >> > Devel mailing list
>> >> > Devel at ovirt.org
>> >> > http://lists.ovirt.org/mailman/listinfo/devel
>> >> _______________________________________________
>> >> Devel mailing list
>> >> Devel at ovirt.org
>> >> http://lists.ovirt.org/mailman/listinfo/devel