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Guest network is created on wrong physical network when multiple physical networks exist #12941
Description
problem
When multiple physical networks are configured for guest traffic—one using VXLAN-based isolation and another using VLAN-based isolation—creating a new L2 guest network via the UI:
Infrastructure -> Physical Networks -> Traffic Types -> Add Guest
results in the network being created on the VXLAN-based physical network, regardless of the intended isolation type.
versions
-
Hypervisor: KVM
-
Network setup:
- Multiple physical networks for guest traffic
- VXLAN + VLAN isolation types
- KVM agent configuration:
guest.network.device=broverlay
ACS version: 4.22.0
OS: Ubuntu 24.04.3 LTS
The steps to reproduce the bug
- Configure two physical networks for guest traffic:
- One with VXLAN-based isolation (kvmnetworklabel: broverlay)
- One with VLAN-based isolation (kvmnetworklabel: brtrunk)
-
Ensure KVM hosts are configured with:
guest.network.device=broverlay -
Navigate to:
Infrastructure -> Physical Networks -> Traffic Types -> Add Guest -
Attempt to create a new L2 guest network with VLAN isolation
Expected result
The guest network should be created on the physical network from which the action was initiated (i.e., the selected VLAN-based physical network)
Actual result
The guest network is created on the VXLAN-based physical network, not on the selected one
What to do about it?
Using cmk, the VLAN-based guest network can be created successfully by explicitly specifying the physical network ID.
Currently, the UI does not allow selecting the physical network when creating a guest network under Network -> Guest Networks; this option should be added.
Activity
weizhouapache commentedon Apr 1, 2026
@akoskuczi-bw
what are the tags of the physical networks and L2 network offerings ?
akoskuczi-bw commentedon Apr 1, 2026
@weizhouapache
cmk list networkofferings id="51b37ee3-6a76-43f7-a235-2b72759306c3" filter=tags,name
{
"count": 1,
"networkoffering": [
{
"name": "DefaultL2NetworkOfferingConfigDriveVlan"
}
]
}
cmk listphysicalnetworks
{
"count": 5,
"physicalnetwork": [
{
"broadcastdomainrange": "ZONE",
"id": "c6e00f00-012d-427c-ad59-5eff383a06ea",
"isolationmethods": "VLAN",
"name": "PN-Management",
"state": "Enabled",
"zoneid": "3e69da92-3496-4e85-a996-526087ba81ee",
"zonename": "Zone-A"
},
{
"broadcastdomainrange": "ZONE",
"id": "e12c90ff-b805-47aa-bb95-7a6208d68dbf",
"isolationmethods": "VLAN",
"name": "PN-Storage",
"state": "Enabled",
"zoneid": "3e69da92-3496-4e85-a996-526087ba81ee",
"zonename": "Zone-A"
},
{
"broadcastdomainrange": "ZONE",
"id": "6072a5eb-9d1f-46b5-bdea-f531aaf2bcb7",
"isolationmethods": "VLAN",
"name": "PN-Public",
"state": "Enabled",
"zoneid": "3e69da92-3496-4e85-a996-526087ba81ee",
"zonename": "Zone-A"
},
{
"broadcastdomainrange": "ZONE",
"id": "73de3452-4500-4c2c-8e47-6f1baa57fba0",
"isolationmethods": "VXLAN",
"name": "PN-Overlay",
"state": "Enabled",
"vlan": "10000-90000",
"zoneid": "3e69da92-3496-4e85-a996-526087ba81ee",
"zonename": "Zone-A"
},
{
"broadcastdomainrange": "ZONE",
"id": "476b73b1-be37-4b83-a579-88a7360662a8",
"isolationmethods": "VLAN",
"name": "PN-Trunk",
"state": "Enabled",
"tags": "Trunk-network",
"zoneid": "3e69da92-3496-4e85-a996-526087ba81ee",
"zonename": "Zone-A"
}
]
}
cmk listtraffictypes physicalnetworkid="73de3452-4500-4c2c-8e47-6f1baa57fba0"
{
"count": 1,
"traffictype": [
{
"id": "8a21cbf3-a4d7-4c5e-80d5-15eadf8faa50",
"kvmnetworklabel": "broverlay",
"physicalnetworkid": "73de3452-4500-4c2c-8e47-6f1baa57fba0",
"traffictype": "Guest"
}
]
}
cmk listtraffictypes physicalnetworkid="476b73b1-be37-4b83-a579-88a7360662a8"
{
"count": 1,
"traffictype": [
{
"id": "a48c3d29-3e7f-4690-95ea-516ee46abf33",
"kvmnetworklabel": "brtrunk",
"physicalnetworkid": "476b73b1-be37-4b83-a579-88a7360662a8",
"traffictype": "Guest"
}
]
}
I think I get it. So the network offering must include tags that match the ones assigned to the physical network?
akoskuczi-bw commentedon Apr 1, 2026
Based on your advice, the guest network is provisioned correctly when the network offering and the physical network share the same tags.