cannot unlink subnet after commission

Hi Robert,

Could you include in the bug report the version of MAAS that you are using as well as the installation type (deb/snap)?

Could you add the steps to reproduce your issue as well?

MAAS version is 3.2.9

maas-hq-a:~$ dpkg -l maas|tail -1
ii maas 1:3.2.9-12055-g.c3d5597a7-0ubuntu1~20.04.1 all

Its a DEB pkg.

Reproduce the issue:

1.) commission a node
2.) try to unlink the primary (PXE) interface which will fail

From my understanding there is no bug here. The correct usage of that function should be

```
ID_LINK=$(maas admin interface read <your_machine_id> <your_interface_id> | jq ".links[].id")
maas admin interface unlink-subnet <your_machine_id> <your_interface_id> id=$ID_LINK
```

and then your interface should be unlinked. Could you confirm?

Hi,

Unfortunately I cannot confirm that. Unlink should work one-by-one if there are more than one links attached to an interface but it is not working for me. Your solution is to read all links and then unlink also not a solution either. Please again read my posts carefully. I said there is a hidden link, which is a remnant and cannot readable by any API call. This is definitely a BUG I think.

As you can see the ID 5699 is hidden:

HQ-A root@maas-hq-a:/home/ubuntu# maas admin interface unlink-subnet yyb3ck 556 id=1
{"id": ["'1' is not a valid id. It should be one of: '5699', '5700'."]}
HQ-A root@maas-hq-a:/home/ubuntu# maas admin interface read yyb3ck 556|jq '.links[].id'
5700

And If I try to unlink 5700 as a normal API client (Terraform for example) would do, Its failed:

HQ-A root@maas-hq-a:/home/ubuntu# maas admin interface unlink-subnet yyb3ck 556 id=5700
Success.
Machine-readable output follows:
{
    "tags": [],
    "firmware_version": null,
    "link_speed": 0,
    "sriov_max_vf": 0,
    "id": 556,
    "effective_mtu": 1500,
    "name": "ens4",
    "links": [
        {
            "id": 5705,
            "mode": "link_up",
            "subnet": {
                "name": "oam",
                "description": "",
                "vlan": {
                    "vid": 0,
                    "mtu": 1500,
                    "dhcp_on": true,
                    "external_dhcp": null,
                    "relay_vlan": null,
                    "fabric_id": 0,
                    "id": 5001,
                    "secondary_rack": null,
                    "name": "untagged",
                    "fabric": "fabric-0",
                    "primary_rack": "qxr7ms",
                    "space": "undefined",
                    "resource_uri": "/MAAS/api/2.0/vlans/5001/"
                },
                "cidr": "192.168.104.0/24",
                "rdns_mode": 2,
                "gateway_ip": "192.168.104.254",
                "dns_servers": [
                    "192.168.104.11",
                    "192.168.104.12",
                    "192.168.104.7"
                ],
                "allow_dns": true,
                "allow_proxy": true,
                "active_discovery": false,
                "managed": true,
                "disabled_boot_architectures": [],
                "id": 1,
                "space": "undefined",
                "resource_uri": "/MAAS/api/2.0/subnets/1/"
            }
        }
    ],
    "parents": [],
    "link_connected": true,
    "vendor": "Red Hat, Inc.",
    "type": "physical",
    "discovered": [
        {
            "subnet": {
                "name": "oam",
                "description": "",
                "vlan": {
                    "vid": 0,
                    "mtu": 1500,
                    "dhcp_on": true,
                    "external_dhcp": null,
                    "relay_vlan": null,
                    "fabric_id": 0,
                    "id": 5001,
                    "secondary_rack": null,
                    "name": "untagged",
                    "fabric": "fabric-0",
                    "primary_rack": "qxr7ms",
                    "space": "undefined",
                    "resource_uri": "/MAAS/api/2.0/vlans/5001/"
                },
                "cidr": "192.168.104.0/24",
                "rdns_mode": 2,
                "gateway_ip": "192.168.104.254",
                "dns_servers": [
                    "192.168.104.11",
                    "192.168.104.12",
                    "192.168.104.7"
                ],
                "allow_dns": true,
                "allo...

The link you see is of type `link_up` and you can actually ignore it as your interface was properly detached from the subnet already.

Sorry but I cannot ignore this. The subnet is not properly detached. Only the IP Mode went from Auto to Unconfigured. The subnet is still attached to my interface.

Just to clarify I know how MAAS should work and we are using it for years. This problem is a blocker for us because we wants to change the primary link IP mode to STATIC with an API client (automation) and we cannot do that because this weird behavior.

Right, I see. Thanks for reporting this!

Thank you!