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

[Roy Golan]

This is for 4.1 https://gerrit.ovirt.org/#/c/78916/ , track that, it should
be in.

On Tue, 8 Aug 2017 at 15:10 Martin Sivak <msivak at redhat.com> wrote:

> 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
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> >> >> http://lists.ovirt.org/mailman/listinfo/devel
>
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