Re: [vdsm] link state semantics
- Original Message -
From: Antoni Segura Puimedon asegu...@redhat.com
To: vdsm-devel@lists.fedorahosted.org
Cc: Alona Kaplan alkap...@redhat.com
Sent: Tuesday, December 4, 2012 7:32:34 PM
Subject: [vdsm] link state semantics
Hi list!
We are working on the new 3.2 feature for adding support for updating
VM
devices, more specifically at the moment network devices.
There is one point of the design which is not yet consensual and we'd
need to agree on a proper and clean design that would satisfy us all:
My current proposal, as reflected by patch:
http://gerrit.ovirt.org/#/c/9560/5/vdsm_api/vdsmapi-schema.json
and its parent is to have a linkActive boolean that is true for link
status 'up' and false for link status 'down'.
We want to support a none (dummy) network that is used to dissociate
vnics
from any real network. The semantics, as you can see in the patch are
that
unless you specify a network, updateDevice will place the interface
on that
network. However, Adam Litke argues that not specifying a network
should
keep the vnic on the network it currently is, as network is an
optional
parameter and 'linkActive' is also optional and has this preserve
current
state semantics.
I can certainly see the merit of what Adam proposes, and the
implementation
would be that linkActive becomes an enum like so:
{'enum': 'linkState'/* or linkActive */ , 'data': ['up', 'down',
'disconnected']}
If you are going for this use 'linkState'
With this change, network would only be changed if one different than
the current
one is specified and the vnic would be taken to the dummy bridge when
the linkState
would be set to 'disconnected'.
In general +1 for new one, with a little doubt.
It looks a bit inconsistent that we leave the network as is if it omitted from
input,
but if linkState is 'disconnected' we will move it to dummy bridge.
But I can live with it.
There is also an objection, raised by Adam about the semantics of
portMirroring.
The current behavior from my patch is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - No action taken.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to
the specified vnic.
His proposal is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is
currently set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to
the specified vnic.
+1 for Adam's approach, just don't forget to unset portMirroring from all nets
setted before
if they not in new portMirroring = [a,b,z]
I would really welcome comments on this to have finally an agreement
to the api for this
feature.
Best,
Toni
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Re: [vdsm] link state semantics
On Tue, Dec 04, 2012 at 03:10:00PM -0600, Adam Litke wrote:
On Tue, Dec 04, 2012 at 12:32:34PM -0500, Antoni Segura Puimedon wrote:
Hi list!
We are working on the new 3.2 feature for adding support for updating VM
devices, more specifically at the moment network devices.
There is one point of the design which is not yet consensual and we'd
need to agree on a proper and clean design that would satisfy us all:
My current proposal, as reflected by patch:
http://gerrit.ovirt.org/#/c/9560/5/vdsm_api/vdsmapi-schema.json
and its parent is to have a linkActive boolean that is true for link
status 'up' and false for link status 'down'.
We want to support a none (dummy) network that is used to dissociate vnics
from any real network. The semantics, as you can see in the patch are that
unless you specify a network, updateDevice will place the interface on that
network. However, Adam Litke argues that not specifying a network should
keep the vnic on the network it currently is, as network is an optional
parameter and 'linkActive' is also optional and has this preserve current
state semantics.
I can certainly see the merit of what Adam proposes, and the implementation
would be that linkActive becomes an enum like so:
{'enum': 'linkState'/* or linkActive */ , 'data': ['up', 'down',
'disconnected']}
With this change, network would only be changed if one different than the
current
one is specified and the vnic would be taken to the dummy bridge when the
linkState
would be set to 'disconnected'.
There is also an objection, raised by Adam about the semantics of
portMirroring.
The current behavior from my patch is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - No action taken.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
His proposal is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is currently
set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
I would really welcome comments on this to have finally an agreement to the
api for this
feature.
ack for portMirroring semantics. [] must mean no networks are mirrored
to this nic.
I am less sure about allowing a No action taken semantics, as it
add the current state to the API and complicates it. I'd also like to
keep the updateDevice API as similar as possible to vmCreate one.
However, we already have defaults in vmCreate (for pci address
allocation, portmirroring off) so I suppose I can join Adam here.
But this does not mean we should allow a default everywhere. I find it
unintuitive to have a linkState=disconnected, as setting this attribute
should clear the network attribute - they become non-orthogonal. So in
my opinion, a missing network should mean nic is connected to no
network rather than keep current connection.
Dan.
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Re: [vdsm] link state semantics
On Wed, Dec 05, 2012 at 02:21:16PM +0200, Dan Kenigsberg wrote:
On Tue, Dec 04, 2012 at 03:10:00PM -0600, Adam Litke wrote:
On Tue, Dec 04, 2012 at 12:32:34PM -0500, Antoni Segura Puimedon wrote:
Hi list!
We are working on the new 3.2 feature for adding support for updating VM
devices, more specifically at the moment network devices.
There is one point of the design which is not yet consensual and we'd
need to agree on a proper and clean design that would satisfy us all:
My current proposal, as reflected by patch:
http://gerrit.ovirt.org/#/c/9560/5/vdsm_api/vdsmapi-schema.json
and its parent is to have a linkActive boolean that is true for link
status 'up' and false for link status 'down'.
We want to support a none (dummy) network that is used to dissociate vnics
from any real network. The semantics, as you can see in the patch are that
unless you specify a network, updateDevice will place the interface on
that
network. However, Adam Litke argues that not specifying a network should
keep the vnic on the network it currently is, as network is an optional
parameter and 'linkActive' is also optional and has this preserve current
state semantics.
I can certainly see the merit of what Adam proposes, and the
implementation
would be that linkActive becomes an enum like so:
{'enum': 'linkState'/* or linkActive */ , 'data': ['up', 'down',
'disconnected']}
With this change, network would only be changed if one different than the
current
one is specified and the vnic would be taken to the dummy bridge when the
linkState
would be set to 'disconnected'.
There is also an objection, raised by Adam about the semantics of
portMirroring.
The current behavior from my patch is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - No action taken.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
His proposal is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is currently
set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
I would really welcome comments on this to have finally an agreement to
the api for this
feature.
ack for portMirroring semantics. [] must mean no networks are mirrored
to this nic.
I am less sure about allowing a No action taken semantics, as it
add the current state to the API and complicates it. I'd also like to
keep the updateDevice API as similar as possible to vmCreate one.
However, we already have defaults in vmCreate (for pci address
allocation, portmirroring off) so I suppose I can join Adam here.
But this does not mean we should allow a default everywhere. I find it
unintuitive to have a linkState=disconnected, as setting this attribute
should clear the network attribute - they become non-orthogonal. So in
my opinion, a missing network should mean nic is connected to no
network rather than keep current connection.
Hmm, a split second after sending this, I've realized that my suggestion
has a similar non-orthogonality problem: when you remove the network
attribute, you implictly change the linkState to down.
So both options are bad :-(
Still I feel that linkState is a lesser attribute, relative to
network, and it would be better to have network imply linkState and not
vice versa.
Dan.
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Re: [vdsm] link state semantics
On 05/12/12 14:21, Dan Kenigsberg wrote:
On Tue, Dec 04, 2012 at 03:10:00PM -0600, Adam Litke wrote:
On Tue, Dec 04, 2012 at 12:32:34PM -0500, Antoni Segura Puimedon wrote:
Hi list!
We are working on the new 3.2 feature for adding support for updating VM
devices, more specifically at the moment network devices.
There is one point of the design which is not yet consensual and we'd
need to agree on a proper and clean design that would satisfy us all:
My current proposal, as reflected by patch:
http://gerrit.ovirt.org/#/c/9560/5/vdsm_api/vdsmapi-schema.json
and its parent is to have a linkActive boolean that is true for link
status 'up' and false for link status 'down'.
We want to support a none (dummy) network that is used to dissociate vnics
from any real network. The semantics, as you can see in the patch are that
unless you specify a network, updateDevice will place the interface on that
network. However, Adam Litke argues that not specifying a network should
keep the vnic on the network it currently is, as network is an optional
parameter and 'linkActive' is also optional and has this preserve current
state semantics.
I can certainly see the merit of what Adam proposes, and the implementation
would be that linkActive becomes an enum like so:
{'enum': 'linkState'/* or linkActive */ , 'data': ['up', 'down',
'disconnected']}
With this change, network would only be changed if one different than the
current
one is specified and the vnic would be taken to the dummy bridge when the
linkState
would be set to 'disconnected'.
There is also an objection, raised by Adam about the semantics of
portMirroring.
The current behavior from my patch is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - No action taken.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
His proposal is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is currently
set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
I would really welcome comments on this to have finally an agreement to the
api for this
feature.
ack for portMirroring semantics. [] must mean no networks are mirrored
to this nic.
+1, It makes sense.
I am less sure about allowing a No action taken semantics, as it
add the current state to the API and complicates it. I'd also like to
keep the updateDevice API as similar as possible to vmCreate one.
However, we already have defaults in vmCreate (for pci address
allocation, portmirroring off) so I suppose I can join Adam here.
But this does not mean we should allow a default everywhere. I find it
unintuitive to have a linkState=disconnected, as setting this attribute
should clear the network attribute - they become non-orthogonal. So in
my opinion, a missing network should mean nic is connected to no
network rather than keep current connection.
I find the 'disconnect' state a bit problematic, a 'test' I do to see if
things make sense is a comparison to the 'physical' world.
In the physical world a link can have up or down, any other state that
we add is less intuitive and IMO should be avoided.
The 'problematic' status we are trying to express in the API is a
network card that has no wire connected to it, how about using an empty
network name to express that no network is connected to this card?
Then we can keep the semantics of not sending a network-name means no
change in the network.
And I also agree with danken that we should keep the API consistent,
createVM hotplug and updateDevice should behave similarly.
Livnat
Dan.
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Re: [vdsm] link state semantics
On Wed, Dec 05, 2012 at 04:25:48AM -0500, Antoni Segura Puimedon wrote:
- Original Message -
From: Igor Lvovsky ilvov...@redhat.com
To: Antoni Segura Puimedon asegu...@redhat.com
Cc: Alona Kaplan alkap...@redhat.com, vdsm-devel@lists.fedorahosted.org
Sent: Wednesday, December 5, 2012 10:17:50 AM
Subject: Re: [vdsm] link state semantics
- Original Message -
From: Antoni Segura Puimedon asegu...@redhat.com
To: vdsm-devel@lists.fedorahosted.org
Cc: Alona Kaplan alkap...@redhat.com
Sent: Tuesday, December 4, 2012 7:32:34 PM
Subject: [vdsm] link state semantics
Hi list!
We are working on the new 3.2 feature for adding support for
updating
VM
devices, more specifically at the moment network devices.
There is one point of the design which is not yet consensual and
we'd
need to agree on a proper and clean design that would satisfy us
all:
My current proposal, as reflected by patch:
http://gerrit.ovirt.org/#/c/9560/5/vdsm_api/vdsmapi-schema.json
and its parent is to have a linkActive boolean that is true for
link
status 'up' and false for link status 'down'.
We want to support a none (dummy) network that is used to
dissociate
vnics
from any real network. The semantics, as you can see in the patch
are
that
unless you specify a network, updateDevice will place the interface
on that
network. However, Adam Litke argues that not specifying a network
should
keep the vnic on the network it currently is, as network is an
optional
parameter and 'linkActive' is also optional and has this preserve
current
state semantics.
I can certainly see the merit of what Adam proposes, and the
implementation
would be that linkActive becomes an enum like so:
{'enum': 'linkState'/* or linkActive */ , 'data': ['up', 'down',
'disconnected']}
If you are going for this use 'linkState'
With this change, network would only be changed if one different
than
the current
one is specified and the vnic would be taken to the dummy bridge
when
the linkState
would be set to 'disconnected'.
In general +1 for new one, with a little doubt.
It looks a bit inconsistent that we leave the network as is if it
omitted from input,
but if linkState is 'disconnected' we will move it to dummy bridge.
But I can live with it.
Yes, the 'disconnected' overrules the network and that, as you point
out, can be a source of confusion. I propose to add a warning to the
return dictionary that tells the user that setting disconnected overrules
any network setting.
There is also an objection, raised by Adam about the semantics of
portMirroring.
The current behavior from my patch is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - No action taken.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to
the specified vnic.
His proposal is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is
currently set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to
the specified vnic.
+1 for Adam's approach, just don't forget to unset portMirroring from
all nets setted before
if they not in new portMirroring = [a,b,z]
So you're saying:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is
currently set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to
the specified vnic AND unset any other mirroring.
I'm fine with it, I think it is even more complete and correct.
Yes, +1.
I would really welcome comments on this to have finally an
agreement
to the api for this
feature.
Best,
Toni
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--
Adam Litke a...@us.ibm.com
IBM Linux Technology Center
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Re: [vdsm] link state semantics
On Tue, Dec 04, 2012 at 12:32:34PM -0500, Antoni Segura Puimedon wrote:
Hi list!
We are working on the new 3.2 feature for adding support for updating VM
devices, more specifically at the moment network devices.
There is one point of the design which is not yet consensual and we'd
need to agree on a proper and clean design that would satisfy us all:
My current proposal, as reflected by patch:
http://gerrit.ovirt.org/#/c/9560/5/vdsm_api/vdsmapi-schema.json
and its parent is to have a linkActive boolean that is true for link
status 'up' and false for link status 'down'.
We want to support a none (dummy) network that is used to dissociate vnics
from any real network. The semantics, as you can see in the patch are that
unless you specify a network, updateDevice will place the interface on that
network. However, Adam Litke argues that not specifying a network should
keep the vnic on the network it currently is, as network is an optional
parameter and 'linkActive' is also optional and has this preserve current
state semantics.
I can certainly see the merit of what Adam proposes, and the implementation
would be that linkActive becomes an enum like so:
{'enum': 'linkState'/* or linkActive */ , 'data': ['up', 'down',
'disconnected']}
With this change, network would only be changed if one different than the
current
one is specified and the vnic would be taken to the dummy bridge when the
linkState
would be set to 'disconnected'.
There is also an objection, raised by Adam about the semantics of
portMirroring.
The current behavior from my patch is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - No action taken.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
His proposal is:
portMirroring is None or is not set - No action taken.
portMirroring = [] - Unset port mirroring to the vnic that is currently set.
portMirroring = [a,b,z] - Set port mirroring for nets a,b and z to the
specified vnic.
I would really welcome comments on this to have finally an agreement to the
api for this
feature.
+1 to the updated proposal. Is there any better way to do it?
--
Adam Litke a...@us.ibm.com
IBM Linux Technology Center
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