d291213f1e
- This change add a new isolate_vif config option to the OVS plugin. - The isolate_vif option defaults to False for backwards compatiblity with SDN-based deployments. - This change is a partial mitigation of bug 1734320, when isolate_vif is set to True os-vif will assign VIFs to the neutron l2 agent dead VLAN 4095. This should only be set when using the ml2/ovs neutron backend. Change-Id: I87ee9626cc6b4a01465a6b1908bc66bc7be0a4bc Partial-Bug: #1734320
38 lines
2.0 KiB
YAML
38 lines
2.0 KiB
YAML
---
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features:
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In this release the OVS plugin was extended to always plug VIFs even when
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libvirt could plug the vif. This will enable faster migration leveraging
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the multiple port bindings work completed in the Rocky release.
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security:
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In this release an edgecase where libvirt plugged the VIF instead of os-vif
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was addressed. Previously if ``ovs_hybrid_plug`` was set to ``False`` in
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the port binding details, os-vif would only ensure the ovs bridge existed
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and the plugging would be done by libvirt. As a result during live
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migration, there was a short interval where a guest could receive tagged
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broadcast, multicast, or flooded traffic to/from another tenant.
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This vulnerability is described in `bug 1734320`_. By ensuring that
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os-vif always creates the OVS port as part of vif plugging we enable
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neutron to isolate the port prior to nova resuming the VM on the
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destination node. Note that as Nova cannot rely on Neutron to send
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``network-vif-plugged`` events on completion of wiring up an interface
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it cannot wait to receive a notification before proceeding with the
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migration. As a result this is a partial mitigation and additional changes
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will be required to fully address this bug.
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.. _bug 1734320: https://bugs.launchpad.net/neutron/+bug/1734320
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A new config option was introduced for the OVS VIF plugin.
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The ``isolate_vif`` option was added as a partial mitigation of
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`bug 1734320`_. The ``isolate_vif`` option defaults to ``False`` for
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backwards compatibility with SDN controller based OpenStack deployments.
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For all deployments using the reference implementation of ML2/OVS with
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the neutron L2 agents, ``isolate_vif`` should be set to ``True``.
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This option instructs the OVS plugin to assign the VIF to the
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Neutron dead VLAN (4095) when attaching the interface to OVS. By setting
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the VIF's VLAN to this dead VLAN number, we eliminate the small attack
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vector that exists for other tenants to read packets during the VIF's
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bring up.
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