Creating an instance with a bogus `source` config gives a cryptic error

[simondeziel]

With this bogus config:

from pylxd import Client

def create_container(instance_name):
    client = Client()
    print("Creating container")
    config = {
        "name": instance_name,
        # bogus source
        "source": {
            "type": "image",
            "mode": "pull",
            "alias": "ubuntu:22.04",
        },
        "type": "container"
    }
    container = client.instances.create(config, wait=True)
    print("Starting Container")
    container.start(wait=True)

create_container("foo")

We get the following cryptic error:

$ python3 c.py 
Creating container
Traceback (most recent call last):
  File "/home/ubuntu/git/pylxd/c.py", line 19, in <module>
    create_container("foo")
  File "/home/ubuntu/git/pylxd/c.py", line 15, in create_container
    container = client.instances.create(config, wait=True)
  File "/home/ubuntu/git/pylxd/pylxd/models/instance.py", line 343, in create
    client.operations.wait_for_operation(response.json()["operation"])
  File "/home/ubuntu/git/pylxd/pylxd/models/operation.py", line 57, in wait_for_operation
    operation.wait()
  File "/home/ubuntu/git/pylxd/pylxd/models/operation.py", line 94, in wait
    response = self._client.api.operations[self.id].wait.get()
  File "/home/ubuntu/git/pylxd/pylxd/client.py", line 207, in get
    self._assert_response(
  File "/home/ubuntu/git/pylxd/pylxd/client.py", line 178, in _assert_response
    raise exceptions.LXDAPIException(response)
pylxd.exceptions.LXDAPIException: <exception str() failed>

While lxc monitor --pretty has:

# lxc monitor --pretty
DEBUG  [2024-02-26T15:01:52Z] Event listener server handler started         id=33d585a0-2ba3-43bf-9cac-5d8dda84e083 local=/var/snap/lxd/common/lxd/unix.socket remote=@
DEBUG  [2024-02-26T15:01:58Z] Handling API request                          ip=@ method=GET protocol=unix url=/1.0 username=ubuntu
DEBUG  [2024-02-26T15:01:58Z] Handling API request                          ip=@ method=POST protocol=unix url=/1.0/instances username=ubuntu
DEBUG  [2024-02-26T15:01:58Z] Responding to instance create                
DEBUG  [2024-02-26T15:01:58Z] New operation                                 class=task description="Creating instance" operation=49a9e353-a37b-4198-97b8-135d224d56e7 project=default
INFO   [2024-02-26T15:01:58Z] ID: 49a9e353-a37b-4198-97b8-135d224d56e7, Class: task, Description: Creating instance  CreatedAt="2024-02-26 15:01:58.473108941 +0000 UTC" Err= Location=none MayCancel=false Metadata="map[]" Resources="map[containers:[/1.0/instances/foo] instances:[/1.0/instances/foo]]" Status=Pending StatusCode=Pending UpdatedAt="2024-02-26 15:01:58.473108941 +0000 UTC"
INFO   [2024-02-26T15:01:58Z] ID: 49a9e353-a37b-4198-97b8-135d224d56e7, Class: task, Description: Creating instance  CreatedAt="2024-02-26 15:01:58.473108941 +0000 UTC" Err="Image not provided for instance creation" Location=none MayCancel=false Metadata="map[]" Resources="map[containers:[/1.0/instances/foo] instances:[/1.0/instances/foo]]" Status=Failure StatusCode=Failure UpdatedAt="2024-02-26 15:01:58.473108941 +0000 UTC"
DEBUG  [2024-02-26T15:01:58Z] Failure for operation                         class=task description="Creating instance" err="Image not provided for instance creation" operation=49a9e353-a37b-4198-97b8-135d224d56e7 project=default
DEBUG  [2024-02-26T15:01:58Z] Started operation                             class=task description="Creating instance" operation=49a9e353-a37b-4198-97b8-135d224d56e7 project=default
INFO   [2024-02-26T15:01:58Z] ID: 49a9e353-a37b-4198-97b8-135d224d56e7, Class: task, Description: Creating instance  CreatedAt="2024-02-26 15:01:58.473108941 +0000 UTC" Err= Location=none MayCancel=false Metadata="map[]" Resources="map[containers:[/1.0/instances/foo] instances:[/1.0/instances/foo]]" Status=Running StatusCode=Running UpdatedAt="2024-02-26 15:01:58.473108941 +0000 UTC"
DEBUG  [2024-02-26T15:01:58Z] Handling API request                          ip=@ method=GET protocol=unix url=/1.0/operations/49a9e353-a37b-4198-97b8-135d224d56e7 username=ubuntu
DEBUG  [2024-02-26T15:01:58Z] Handling API request                          ip=@ method=GET protocol=unix url=/1.0/operations/49a9e353-a37b-4198-97b8-135d224d56e7/wait username=ubuntu

For reference, a valid source would look like that (equivalent of a lxc launch ubuntu:22.04):

        "source": {
            "type": "image",
            "mode": "pull",
            "server": "https://cloud-images.ubuntu.com/releases",
            "protocol": "simplestreams",
            "alias": "22.04",
        },

[tomponline]

@simondeziel did you reproduce the error?

pytest-cos lxc start cos-bar                 
Error: Failed to handle idmapped storage: No such file or directory: "/var/snap/lxd/common/lxd/storage-pools/default/containers/cos-bar/rootfs"
Try `lxc info --show-log cos-bar` for more info

I'm wondering how LXD got so far as to trying to idmap a non-existent dir because invalid image source was specified.

[simondeziel]

@tomponline no, I cannot reproduce that missing rootfs as it leaves me without any instance after the cryptic error.