After building the current openvswitch master branch today and connecting to it via ODL OVSDB southbound, it was observed that the OVSDB operational MD-SAL was not populated for the OVSDB node. The log trace and investigation showed that the OVS host had an interface type 'stt' in the 'iface_types' column which is not present in the ovsdb.yang model.

Adding the 'stt' interface type to the model resolved the problem.

A better fix would be to ignore unknown interface types.

Log snippet:
2015-06-22 06:37:54,567 | INFO | lt-dispatcher-16 | OvsdbConnectionManager | 171 - org.opendaylight.ovsdb.southbound-impl - 1.1.0.SNAPSHOT | OVSDB Connection from /10.11.21.9:6640
2015-06-22 06:37:54,905 | WARN | n-invoker-impl-0 | TransactionInvokerImpl | 171 - org.opendaylight.ovsdb.southbound-impl - 1.1.0.SNAPSHOT | Exception invoking Transaction:
java.lang.IllegalArgumentException: All keys must be specified for class org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.rev150105.ovsdb.node.attributes.InterfaceTypeEntryKey. Missing key is getInterfaceType. Supplied key is InterfaceTypeEntryKey []
at com.google.common.base.Preconditions.checkArgument(Preconditions.java:145)[51:com.google.guava:18.0.0]
at org.opendaylight.yangtools.binding.data.codec.impl.ValueContext.getAndSerialize(ValueContext.java:46)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.IdentifiableItemCodec.serialize(IdentifiableItemCodec.java:124)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.IdentifiableItemCodec.serialize(IdentifiableItemCodec.java:31)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.KeyedListNodeCodecContext.serialize(KeyedListNodeCodecContext.java:80)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.BindingToNormalizedStreamWriter.startMapEntryNode(BindingToNormalizedStreamWriter.java:156)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.rev150105.ovsdb.node.attributes.InterfaceTypeEntry$StreamWriter.serialize(DataObjectSerializerPrototype.java)[170:org.opendaylight.ovsdb.southbound-api:1.1.0.SNAPSHOT]
at org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.ovsdb.rev150105.OvsdbNodeAugmentation$StreamWriter.serialize(DataObjectSerializerPrototype.java)[170:org.opendaylight.ovsdb.southbound-api:1.1.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.BindingNormalizedNodeCodecRegistry$DataObjectSerializerProxy.serialize(BindingNormalizedNodeCodecRegistry.java:295)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.util.AugmentableDispatchSerializer.emitAugmentation(AugmentableDispatchSerializer.java:79)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.util.AugmentableDispatchSerializer.serialize(AugmentableDispatchSerializer.java:51)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yang.gen.v1.urn.tbd.params.xml.ns.yang.network.topology.rev131021.network.topology.topology.Node$StreamWriter.serialize(DataObjectSerializerPrototype.java)[69:org.opendaylight.yangtools.model.ietf-topology:2013.10.21.7-SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.BindingNormalizedNodeCodecRegistry$DataObjectSerializerProxy.serialize(BindingNormalizedNodeCodecRegistry.java:295)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.yangtools.binding.data.codec.impl.BindingNormalizedNodeCodecRegistry.toNormalizedNode(BindingNormalizedNodeCodecRegistry.java:106)[96:org.opendaylight.yangtools.binding-data-codec:0.7.0.SNAPSHOT]
at org.opendaylight.controller.md.sal.binding.impl.BindingToNormalizedNodeCodec.toNormalizedNode(BindingToNormalizedNodeCodec.java:133)[147:org.opendaylight.controller.sal-binding-broker-impl:1.2.0.SNAPSHOT]
at org.opendaylight.controller.md.sal.binding.impl.AbstractWriteTransaction.merge(AbstractWriteTransaction.java:53)[147:org.opendaylight.controller.sal-binding-broker-impl:1.2.0.SNAPSHOT]
at org.opendaylight.controller.md.sal.binding.impl.BindingDOMWriteTransactionAdapter.merge(BindingDOMWriteTransactionAdapter.java:46)[147:org.opendaylight.controller.sal-binding-broker-impl:1.2.0.SNAPSHOT]
at org.opendaylight.ovsdb.southbound.transactions.md.OpenVSwitchUpdateCommand.execute(OpenVSwitchUpdateCommand.java:91)[171:org.opendaylight.ovsdb.southbound-impl:1.1.0.SNAPSHOT]
at org.opendaylight.ovsdb.southbound.transactions.md.OvsdbOperationalCommandAggregator.execute(OvsdbOperationalCommandAggregator.java:30)[171:org.opendaylight.ovsdb.southbound-impl:1.1.0.SNAPSHOT]
at org.opendaylight.ovsdb.southbound.transactions.md.TransactionInvokerImpl.run(TransactionInvokerImpl.java:77)[171:org.opendaylight.ovsdb.southbound-impl:1.1.0.SNAPSHOT]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)[:1.7.0_65]
at java.util.concurrent.FutureTask.run(FutureTask.java:262)[:1.7.0_65]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)[:1.7.0_65]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)[:1.7.0_65]
at java.lang.Thread.run(Thread.java:745)[:1.7.0_65]