Network Extension feature doesn't persist the vlan information

### problem

Network Extension feature doesn't persist the vlan information

### versions

ACS 4.23, KVM

### The steps to reproduce the bug

Follow the steps mentioned here to register network extension

https://github.com/apache/cloudstack-extensions/blob/network-namespace/Network-Namespace/README.md

1. Create a network offering with vlan enabled

2. Create a network based on the above network offering

3. Launch a vm in the network > Vm deployed successfully

4. Destroy the vm

After some time the network state changes from implemented to allocated since there are no vm's

5. Check the networks table, the brodcast_uri changes to NULL

6. The subsequent vm launch will result in a failure

logs
```
root@Cloudstack-423:/var/log/cloudstack/management# cat /var/log/cloudstack/management/management-server.log.2026-09-07 | grep -i "logid:63df11b4" | grep -iE "Script output|failed with exit code|Cannot find|Ensuring network
device|Implementing network extension|applyFWRules|Applying|dhcp|dns"
2026-09-07 11:14:23,762 DEBUG [c.c.c.CapacityManagerImpl] (API-Job-Executor-49:[ctx-564cbc63, job-1216, ctx-099a3943, FirstFitRoutingAllocator]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:24,714 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:24,716 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:24,717 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:24,756 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Implementing network extension for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (VLAN null)
2026-09-07 11:14:24,756 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={})
2026-09-07 11:14:25,306 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:25,316 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:25,628 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:27,212 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: Cannot find device "vn--227"
2026-09-07 11:14:27,212 ERROR [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Network extension script implement-network failed with exit code 3: Cannot find device "vn--227"
2026-09-07 11:14:27,261 DEBUG [c.c.n.f.FirewallManagerImpl] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) applying default firewall egress rules
2026-09-07 11:14:27,263 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) applyFWRules: network=Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} activeRules=0 defaultEgressAllow=true
2026-09-07 11:14:27,263 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:27,565 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:29,149 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: apply-fw-rules: built 0 ingress rule(s) across 0 public IP(s), 0 egress rule(s), default_egress=ALLOW, default-DROP chains for 0 static-NAT IP(s) with no rules
2026-09-07 11:14:29,149 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Ignoring non-JSON script output: apply-fw-rules: built 0 ingress rule(s) across 0 public IP(s), 0 egress rule(s), default_egress=ALLOW, default-DROP chains for 0 static-NAT IP(s) with no rules
2026-09-07 11:14:29,155 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Applying 1 IPs for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40}
2026-09-07 11:14:29,156 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:29,463 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:31,012 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:31,319 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:33,117 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:33,117 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-63:[ctx-806840fb, job-1216/job-1217, ctx-f951d8a4]) (logid:63df11b4) Hosts's actual total RAM: (6.57 GB) 7053959168 and RAM after applying overprovisioning: (6.57 GB) 7053959168
2026-09-07 11:14:34,682 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32, FirstFitRoutingAllocator]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:34,709 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:34,711 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:34,711 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:34,751 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Implementing network extension for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (VLAN null)
2026-09-07 11:14:34,751 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={})
2026-09-07 11:14:35,058 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:35,084 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:35,391 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:36,929 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: Cannot find device "vn--227"
2026-09-07 11:14:36,929 ERROR [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Network extension script implement-network failed with exit code 3: Cannot find device "vn--227"
2026-09-07 11:14:36,978 DEBUG [c.c.n.f.FirewallManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) applying default firewall egress rules
2026-09-07 11:14:36,982 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) applyFWRules: network=Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} activeRules=0 defaultEgressAllow=true
2026-09-07 11:14:36,982 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:37,288 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:38,864 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: apply-fw-rules: built 0 ingress rule(s) across 0 public IP(s), 0 egress rule(s), default_egress=ALLOW, default-DROP chains for 0 static-NAT IP(s) with no rules
2026-09-07 11:14:38,864 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Ignoring non-JSON script output: apply-fw-rules: built 0 ingress rule(s) across 0 public IP(s), 0 egress rule(s), default_egress=ALLOW, default-DROP chains for 0 static-NAT IP(s) with no rules
2026-09-07 11:14:38,868 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Applying 1 IPs for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40}
2026-09-07 11:14:38,868 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:39,170 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:40,738 INFO [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Ensuring network device for network Network {"id": 227, "name": "test6", "uuid": "2e690dff-8d4e-4603-8454-7e06672bdc56", "networkofferingid": 40} (current={"host":"192.168.55.179","namespace":"cs-net-227"})
2026-09-07 11:14:41,046 DEBUG [o.a.c.f.e.n.NetworkExtensionElement] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Script output: {"host":"192.168.55.179","namespace":"cs-net-227"}
2026-09-07 11:14:42,881 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Hosts's actual total CPU: 12748 and CPU after applying overprovisioning: 12748
2026-09-07 11:14:42,881 DEBUG [c.c.c.CapacityManagerImpl] (Work-Job-Executor-64:[ctx-69cc0292, job-1216/job-1218, ctx-c4e49f32]) (logid:63df11b4) Hosts's actual total RAM: (6.57 GB) 7053959168 and RAM after applying overprovisioning: (6.57 GB) 7053959168

```

```

*************************** 28. row ***************************
id: 227
name: test6
uuid: 2e690dff-8d4e-4603-8454-7e06672bdc56
display_text: test6
traffic_type: Guest
broadcast_domain_type: Vlan
broadcast_uri: NULL
gateway: 10.1.1.1
cidr: 10.1.1.0/24
mode: Dhcp
network_offering_id: 40
physical_network_id: 200
data_center_id: 1
guru_name: NetworkExtensionGuestNetworkGuru
state: Allocated
related: 227
domain_id: 1
account_id: 2
dns1: 8.8.8.8
dns2: NULL
ip6dns1: NULL
ip6dns2: NULL
guru_data: NULL
set_fields: 0
acl_type: Account
network_domain: cs2cloud.internal
reservation_id: f9fe4b5c-831e-4903-9258-7ab5338e27bd
guest_type: Isolated
restart_required: 0
created: 2026-09-07 10:31:15
removed: NULL
specify_ip_ranges: 0
vpc_id: NULL
ip6_gateway: NULL
ip6_cidr: NULL
network_cidr: NULL
display_network: 1
network_acl_id: NULL
streched_l2: 0
redundant: 0
external_id: NULL
public_mtu: 1500
private_mtu: 1500
keep_mac_address_on_public_nic: 1

```

### What to do about it?

The vlan information of the guest network should be persisted in the database so that the vlan

Root cause found

```
NetworkExtensionGuestNetworkGuru.implement() (server/src/main/java/com/cloud/network/guru/NetworkExtensionGuestNetworkGuru.java:104-120):

public Network implement(final Network network, final NetworkOffering offering, final DeployDestination dest, final ReservationContext context)
throws InsufficientVirtualNetworkCapacityException {
...
// The broadcast_domain_type and broadcast_uri are set by the extension script output
final NetworkVO implemented = getNetworkVO(network, offering, physicalNetworkId);
return implemented;
}

private static NetworkVO getNetworkVO(Network network, NetworkOffering offering, Long physicalNetworkId) {
final NetworkVO implemented = new NetworkVO(...);
...
if (network.getBroadcastUri() != null) {
implemented.setBroadcastUri(network.getBroadcastUri()); // only copies through — never allocates
}
return implemented;
}

```
Compare to the parent it extends, GuestNetworkGuru.implement() (server/src/main/java/com/cloud/network/guru/GuestNetworkGuru.java:398), which calls allocateVnet():

```
protected void allocateVnet(final Network network, final NetworkVO implemented, final long dcId, final long physicalNetworkId, final String reservationId)
throws InsufficientVirtualNetworkCapacityException {
if (network.getBroadcastUri() == null) {
final String vnet = _dcDao.allocateVnet(dcId, physicalNetworkId, network.getAccountId(), reservationId, ...);
implemented.setBroadcastUri(BUri(vnet)); // auto-allocates a fresh
VLAN
} else {
implemented.setBroadcastUri(n
}
}

```

Start with Network-Namespace/README.md and the NetworkExtensionElement entry point shown in the logs. Trace the network lifecycle after VM destruction and inspect how the networks table stores broadcast_uri. Done means VLAN information remains persisted after the network returns to allocated, and a subsequent VM launch succeeds.

由索引模型根据 Issue 内容生成。