Created attachment 1372065 [details]
engine log

Description of problem:
Engine requires to set a gateway in order to sync a network

Can't sync network with combination of static IP(no GW) and VM<>non-VM property.
Can't sync network with combination of static IP(no GW) and vlan/non-vlan property.

Looks like engine requires to set a gateway in order to sync the network.

'Error while executing action: 

zeus-vds1.qa.lab.tlv.redhat.com:
must match "^\b((25[0-5]|2[0-4]\d|[01]\d\d|\d?\d)\_){3}(25[0-5]|2[0-4]\d|[01]\d\d|\d?\d)"
Attribute: ipConfiguration.iPv4Addresses[0].gateway'

2017-12-25 08:52:51,296+02 WARN  [org.ovirt.engine.core.bll.network.host.HostSetupNetworksCommand] (default task-4) [2535d33c] Validation of action 'HostSetupNetworks' failed for user admin@internal-authz. Reasons: VAR__ACTION__SETUP,VAR__TYPE__NETWORKS,must match "^\b((25[0-5]|2[0-4]\d|[01]\d\d|\d?\d)\.){3}(25[0-5]|2[0-4]\d|[01]\d\d|\d?\d)",$flags [Ljavax.validation.constraints.Pattern$Flag;@6f99d3a6,$regexp ^\b((25[0-5]|2[0-4]\d|[01]\d\d|\d?\d)\.){3}(25[0-5]|2[0-4]\d|[01]\d\d|\d?\d),$groups [Ljava.lang.Class;@1867ff02,$message {javax.validation.constraints.Pattern.message},$payload [Ljava.lang.Class;@1474d76a,ACTION_TYPE_FAILED_ATTRIBUTE_PATH,$path ipConfiguration.iPv4Addresses[0].gateway,$validatedValue 
2017-12-25 08:52:51,312+02 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (default task-4) [2535d33c] EVENT_ID: PERSIST_SETUP_NETWORK_ON_HOST_FAILED(10,904), (1/1): Failed to apply changes on host zeus-vds1.qa.lab.tlv.redhat.com. (User: admin@internal-authz)
2017-12-25 08:52:51,325+02 ERROR [org.ovirt.engine.core.bll.network.host.SyncAllHostNetworksCommand] (default task-4) [2535d33c] Transaction rolled-back for command 'org.ovirt.engine.core.bll.network.host.SyncAllHostNetworksCommand'.
2017-12-25 08:52:51,337+02 ERROR [org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector] (default task-4) [2535d33c] EVENT_ID: HOST_SYNC_ALL_NETWORKS_FAILED(10,900), Failed to sync all host zeus-vds1.qa.lab.tlv.redhat.com networks


Version-Release number of selected component (if applicable):
4.2.0.2-0.1.el7

How reproducible:
100% 

Steps to Reproduce:
Scenario1 - 
1. Create 2 DCs, run host in DC1
2. Create network called 'net1' on both DCs, on DC1 set it as VM network, on DC2 set it as non-VM network. Attach net1 to host in DC1 with static IP without GW.
3. Set host to maintenance and  Move the host to DC2(net1 network is now out-of-sync and non-VM network in DC2)
4. Try to sync the network

Scenario2 - 
1. Create 2 DCs, run host in DC1
2. Create network called 'net1' on both DCs, on DC1 set it with vlan tag 11, on DC2 set it as non-vlan network. Attach 'net1' to host in DC1 with static IP without GW.
3. Set host to maintenance and  Move the host to DC2(net1 network is now out-of-sync and non-vlan network in DC2)
4. Try to sync the network

Actual results:
Failed - engine expecting to set GW 

Expected results:
Sync should work if static IP has no gateway as well.