Re: [openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
On 02/10/2014 05:46 AM, Mathieu Rohon wrote: Hi, one other comment inline : Hi Mathieu, see below: On Wed, Feb 5, 2014 at 5:01 PM, Robert Kukura rkuk...@redhat.com wrote: On 02/05/2014 09:10 AM, Henry Gessau wrote: Bob, this is fantastic, I really appreciate all the detail. A couple of questions ... On Wed, Feb 05, at 2:16 am, Robert Kukura rkuk...@redhat.com wrote: A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently
Re: [openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
On 02/05/2014 10:47 AM, Mathieu Rohon wrote: Hi, thanks for this great proposal Just following up on the one comment below: On Wed, Feb 5, 2014 at 3:10 PM, Henry Gessau ges...@cisco.com wrote: Bob, this is fantastic, I really appreciate all the detail. A couple of questions ... On Wed, Feb 05, at 2:16 am, Robert Kukura rkuk...@redhat.com wrote: A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently unbound binding states
Re: [openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
Hi, one other comment inline : On Wed, Feb 5, 2014 at 5:01 PM, Robert Kukura rkuk...@redhat.com wrote: On 02/05/2014 09:10 AM, Henry Gessau wrote: Bob, this is fantastic, I really appreciate all the detail. A couple of questions ... On Wed, Feb 05, at 2:16 am, Robert Kukura rkuk...@redhat.com wrote: A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently unbound binding states as shown. If a value for binding:host_id was supplied,
Re: [openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
Bob, this is fantastic, I really appreciate all the detail. A couple of questions ... On Wed, Feb 05, at 2:16 am, Robert Kukura rkuk...@redhat.com wrote: A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently unbound binding states as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value
Re: [openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
Hi, thanks for this great proposal On Wed, Feb 5, 2014 at 3:10 PM, Henry Gessau ges...@cisco.com wrote: Bob, this is fantastic, I really appreciate all the detail. A couple of questions ... On Wed, Feb 05, at 2:16 am, Robert Kukura rkuk...@redhat.com wrote: A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently unbound binding states as shown. If a value for binding:host_id was supplied, binding will occur afterwards as
Re: [openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
On 02/05/2014 09:10 AM, Henry Gessau wrote: Bob, this is fantastic, I really appreciate all the detail. A couple of questions ... On Wed, Feb 05, at 2:16 am, Robert Kukura rkuk...@redhat.com wrote: A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently unbound binding states as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']:
[openstack-dev] [neutron][ml2] Port binding information, transactions, and concurrency
A couple of interrelated issues with the ML2 plugin's port binding have been discussed over the past several months in the weekly ML2 meetings. These effect drivers being implemented for icehouse, and therefore need to be addressed in icehouse: * MechanismDrivers need detailed information about all binding changes, including unbinding on port deletion (https://bugs.launchpad.net/neutron/+bug/1276395) * MechanismDrivers' bind_port() methods are currently called inside transactions, but in some cases need to make remote calls to controllers or devices (https://bugs.launchpad.net/neutron/+bug/1276391) * Semantics of concurrent port binding need to be defined if binding is moved outside the triggering transaction. I've taken the action of writing up a unified proposal for resolving these issues, which follows... 1) An original_bound_segment property will be added to PortContext. When the MechanismDriver update_port_precommit() and update_port_postcommit() methods are called and a binding previously existed (whether its being torn down or not), this property will provide access to the network segment used by the old binding. In these same cases, the portbinding extension attributes (such as binding:vif_type) for the old binding will be available via the PortContext.original property. It may be helpful to also add bound_driver and original_bound_driver properties to PortContext that behave similarly to bound_segment and original_bound_segment. 2) The MechanismDriver.bind_port() method will no longer be called from within a transaction. This will allow drivers to make remote calls on controllers or devices from within this method without holding a DB transaction open during those calls. Drivers can manage their own transactions within bind_port() if needed, but need to be aware that these are independent from the transaction that triggered binding, and concurrent changes to the port could be occurring. 3) Binding will only occur after the transaction that triggers it has been completely processed and committed. That initial transaction will unbind the port if necessary. Four cases for the initial transaction are possible: 3a) In a port create operation, whether the binding:host_id is supplied or not, all drivers' port_create_precommit() methods will be called, the initial transaction will be committed, and all drivers' port_create_postcommit() methods will be called. The drivers will see this as creation of a new unbound port, with PortContext properties as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original: None PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: supplied value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3b) Similarly, in a port update operation on a previously unbound port, all drivers' port_update_precommit() and port_update_postcommit() methods will be called, with PortContext properies as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value or None PortContext.original['binding:vif_type']: 'unbound' or 'binding_failed' PortContext.original_bound_segment: None PortContext.original_bound_driver: None PortContext.current['binding:host_id']: current value or None PortContext.current['binding:vif_type']: 'unbound' PortContext.bound_segment: None PortContext.bound_driver: None 3c) In a port update operation on a previously bound port that does not trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting unchanged binding states as shown. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: previous value PortContext.current['binding:vif_type']: previous value PortContext.bound_segment: previous value PortContext.bound_driver: previous value 3d) In a the port update operation on a previously bound port that does trigger unbinding or rebinding, all drivers' update_port_precommit() and update_port_postcommit() methods will be called with PortContext properties reflecting the previously bound and currently unbound binding states as shown. If a value for binding:host_id was supplied, binding will occur afterwards as described in 4 below. PortContext.original['binding:host_id']: previous value PortContext.original['binding:vif_type']: previous value PortContext.original_bound_segment: previous value PortContext.original_bound_driver: previous value PortContext.current['binding:host_id']: new or current value PortContext.current['binding:vif_type']: 'unbound'
