az aks start crash

[dod38fr]

Describe the bug

az aks start --help crashes, even without options

Related command

az aks start
az aks stop

Errors

$ az aks start 
The command failed with an unexpected error. Here is the traceback:
'NoneType' object has no attribute '__dict__'
Traceback (most recent call last):
  File "/opt/az/lib/python3.13/site-packages/knack/cli.py", line 233, in invoke
    cmd_result = self.invocation.execute(args)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 571, in execute
    self.commands_loader.load_arguments(command)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/__init__.py", line 618, in load_arguments
    self.command_table[command].load_arguments()  # this loads the arguments via reflection
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 321, in load_arguments
    super().load_arguments()
    ~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/knack/commands.py", line 104, in load_arguments
    cmd_args = self.arguments_loader()
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 124, in arguments_loader
    op = self.get_op_handler(self.op_path)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 54, in get_op_handler
    get_versioned_sdk_path(self.cli_ctx.cloud.profile, rt,
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                           operation_group=self.operation_group))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 486, in get_versioned_sdk_path
    api_version = getattr(api_version, operation_group)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 281, in __getattr__
    self._resolve()
    ~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 268, in _resolve
    for operation_group_name, operation_type in self._client_type.__dict__.items():
                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute '__dict__'. Did you mean: '__dir__'?
To check existing issues, please visit: https://github.com/Azure/azure-cli/issues

Issue script & Debug output

 az aks start --debug
cli.knack.cli: Command arguments: ['aks', 'start', '--debug']
cli.knack.cli: __init__ debug log:
Enable color in terminal.
cli.knack.cli: Event: Cli.PreExecute []
cli.knack.cli: Event: CommandParser.OnGlobalArgumentsCreate [<function CLILogging.on_global_arguments at 0x7fd77ac4a840>, <function OutputProducer.on_global_arguments at 0x7fd77a982700>, <function CLIQuery.on_global_arguments at 0x7fd77a9c0860>]
cli.knack.cli: Event: CommandInvoker.OnPreCommandTableCreate []
cli.azure.cli.core: Modules found from index for 'aks': ['azure.cli.command_modules.acs', 'azext_aks_preview', 'azure.cli.command_modules.serviceconnector']
cli.azure.cli.core: Loading command modules...
cli.azure.cli.core: Loaded command modules in parallel:
cli.azure.cli.core: Name                  Load Time    Groups  Commands
cli.azure.cli.core: serviceconnector          0.245        20       331
cli.azure.cli.core: acs                       0.250        18        96
cli.azure.cli.core: Total (2)                 0.250        38       427
cli.azure.cli.core: These extensions are not installed and will be skipped: ['azext_ai_examples', 'azext_next']
cli.azure.cli.core: Loading extensions:
cli.azure.cli.core: Name                  Load Time    Groups  Commands  Directory
cli.knack.cli: Event: CommandLoader.OnLoadCommandTable []
cli.azure.cli.core: aks-preview               0.007        22       103  /home/domi/.azure/cliextensions/aks-preview
cli.azure.cli.core: Total (1)                 0.007        22       103  
cli.azure.cli.core: Loaded 45 groups, 457 commands.
cli.azure.cli.core: Found a match in the command table.
cli.azure.cli.core: Raw command  : aks start
cli.azure.cli.core: Command table: aks start
cli.knack.cli: Event: CommandInvoker.OnPreCommandTableTruncate [<function AzCliLogging.init_command_file_logging at 0x7fd7798e3420>]
cli.azure.cli.core.azlogging: metadata file logging enabled - writing logs to '/home/domi/.azure/commands/2026-04-02.11-05-04.aks_start.623044.log'.
az_command_data_logger: command args: aks start --debug
cli.knack.cli: Event: CommandInvoker.OnPreArgumentLoad [<function register_global_subscription_argument.<locals>.add_subscription_parameter at 0x7fd779934f40>]
cli.azure.cli.core.profiles._shared: Traceback (most recent call last):
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 455, in _get_attr
    op = import_module(full_mod_path)
  File "/opt/az/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1310, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 1023, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/home/domi/.azure/cliextensions/aks-preview/azext_aks_preview/vendored_sdks/__init__.py", line 6, in <module>
    __import__('pkg_resources').declare_namespace(__name__)
    ~~~~~~~~~~^^^^^^^^^^^^^^^^^
ModuleNotFoundError: No module named 'pkg_resources'

cli.azure.cli.core.azclierror: Traceback (most recent call last):
  File "/opt/az/lib/python3.13/site-packages/knack/cli.py", line 233, in invoke
    cmd_result = self.invocation.execute(args)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 571, in execute
    self.commands_loader.load_arguments(command)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/__init__.py", line 618, in load_arguments
    self.command_table[command].load_arguments()  # this loads the arguments via reflection
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 321, in load_arguments
    super().load_arguments()
    ~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/knack/commands.py", line 104, in load_arguments
    cmd_args = self.arguments_loader()
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 124, in arguments_loader
    op = self.get_op_handler(self.op_path)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 54, in get_op_handler
    get_versioned_sdk_path(self.cli_ctx.cloud.profile, rt,
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                           operation_group=self.operation_group))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 486, in get_versioned_sdk_path
    api_version = getattr(api_version, operation_group)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 281, in __getattr__
    self._resolve()
    ~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 268, in _resolve
    for operation_group_name, operation_type in self._client_type.__dict__.items():
                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute '__dict__'. Did you mean: '__dir__'?

cli.azure.cli.core.azclierror: The command failed with an unexpected error. Here is the traceback:
az_command_data_logger: The command failed with an unexpected error. Here is the traceback:
cli.azure.cli.core.azclierror: 'NoneType' object has no attribute '__dict__'
Traceback (most recent call last):
  File "/opt/az/lib/python3.13/site-packages/knack/cli.py", line 233, in invoke
    cmd_result = self.invocation.execute(args)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 571, in execute
    self.commands_loader.load_arguments(command)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/__init__.py", line 618, in load_arguments
    self.command_table[command].load_arguments()  # this loads the arguments via reflection
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 321, in load_arguments
    super().load_arguments()
    ~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/knack/commands.py", line 104, in load_arguments
    cmd_args = self.arguments_loader()
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 124, in arguments_loader
    op = self.get_op_handler(self.op_path)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 54, in get_op_handler
    get_versioned_sdk_path(self.cli_ctx.cloud.profile, rt,
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                           operation_group=self.operation_group))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 486, in get_versioned_sdk_path
    api_version = getattr(api_version, operation_group)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 281, in __getattr__
    self._resolve()
    ~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 268, in _resolve
    for operation_group_name, operation_type in self._client_type.__dict__.items():
                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute '__dict__'. Did you mean: '__dir__'?
az_command_data_logger: 'NoneType' object has no attribute '__dict__'
Traceback (most recent call last):
  File "/opt/az/lib/python3.13/site-packages/knack/cli.py", line 233, in invoke
    cmd_result = self.invocation.execute(args)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 571, in execute
    self.commands_loader.load_arguments(command)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/__init__.py", line 618, in load_arguments
    self.command_table[command].load_arguments()  # this loads the arguments via reflection
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/__init__.py", line 321, in load_arguments
    super().load_arguments()
    ~~~~~~~~~~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/knack/commands.py", line 104, in load_arguments
    cmd_args = self.arguments_loader()
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 124, in arguments_loader
    op = self.get_op_handler(self.op_path)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/commands/command_operation.py", line 54, in get_op_handler
    get_versioned_sdk_path(self.cli_ctx.cloud.profile, rt,
    ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                           operation_group=self.operation_group))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 486, in get_versioned_sdk_path
    api_version = getattr(api_version, operation_group)
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 281, in __getattr__
    self._resolve()
    ~~~~~~~~~~~~~^^
  File "/opt/az/lib/python3.13/site-packages/azure/cli/core/profiles/_shared.py", line 268, in _resolve
    for operation_group_name, operation_type in self._client_type.__dict__.items():
                                                ^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute '__dict__'. Did you mean: '__dir__'?
To check existing issues, please visit: https://github.com/Azure/azure-cli/issues
cli.knack.cli: Event: Cli.PostExecute [<function AzCliLogging.deinit_cmd_metadata_logging at 0x7fd7798e36a0>]
az_command_data_logger: exit code: 1
cli.__main__: Command ran in 0.421 seconds (init: 0.120, invoke: 0.301)
telemetry.main: Begin splitting cli events and extra events, total events: 1
telemetry.client: Accumulated 0 events. Flush the clients.
telemetry.main: Finish splitting cli events and extra events, cli events: 1
telemetry.save: Save telemetry record of length 8160 in cache file under /home/domi/.azure/telemetry/20260402110505039
telemetry.main: Begin creating telemetry upload process.
telemetry.process: Creating upload process: "/opt/az/bin/python3 /opt/az/lib/python3.13/site-packages/azure/cli/telemetry/__init__.py /home/domi/.azure /home/domi/.azure/telemetry/20260402110505039"
telemetry.process: Return from creating process 623065
telemetry.main: Finish creating telemetry upload process.

Expected behavior

no crash

Environment Summary

$ az --version
azure-cli 2.84.0

core 2.84.0
telemetry 1.1.0

Extensions:
aks-preview 14.0.0b4
aksarc 1.5.62
connectedk8s 1.10.10
ssh 2.0.6

Dependencies:
msal 1.35.0b1
azure-mgmt-resource 24.0.0

Python location '/opt/az/bin/python3'
Config directory '/home/domi/.azure'
Extensions directory '/home/domi/.azure/cliextensions'

Python (Linux) 3.13.11 (main, Feb 25 2026, 02:29:30) [GCC 12.2.0]

Legal docs and information: aka.ms/AzureCliLegal

Your CLI is up-to-date.

Additional context

Running on Debian/sid amd64

[yonzhan]

Thank you for opening this issue, we will look into it.

[github-actions]

Here are some similar issues that might help you. Please check if they can solve your problem.

• az aks exception #31345

---

Possible solution (Extracted from existing issue, might be incorrect; please verify carefully)

Solution 1:

Downgrading aks-preview extension worked for me:

az extension remove --name aks-preview
az extension add --name aks-preview --version 14.0.0b3

Reference:

• az aks exception #31345 (comment)

Solution 2:

Please run pip install azure-mgmt-core==1.5.0 in your python environment as a workaround.
Raised issue #31322 to cli team to completely fix the problem.

Reference:

• az aks exception #31345 (comment)

Solution 3:

I can see forcing pip install azure-mgmt-core==1.5.0, but it didn't help me.

this worked for me: az extension add --name aks-preview --version 14.0.0b3

Reference:

• az aks exception #31345 (comment)

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[microsoft-github-policy-service]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @mbifeld, @FumingZhang, @andyliuliming, @act-observability-squad.

[microsoft-github-policy-service]

🔔 Routing this issue to @act-observability-squad.

[microsoft-github-policy-service]

Thanks for the feedback! We are routing this to the appropriate team for follow-up. cc @mbifeld, @FumingZhang, @andyliuliming, @act-observability-squad.

[microsoft-github-policy-service]

🔔 Routing this issue to @act-observability-squad.