az aks start crash

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

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

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)

Powered by issue-sentinel

Mitchell Bifeld (@mbifeld)

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

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

Mitchell Bifeld (@mbifeld)

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

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

Mitchell Bifeld (@mbifeld)

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

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

Mitchell Bifeld (@mbifeld)

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

This aks start crash issue - I can investigate the root cause and submit a fix. Available for paid bug fixes. DM me. USDT/ETH preferred.

Dominique Dumont (@dod38fr)

Hi Dominique Dumont (@dod38fr), the issue has been resolved in a newer version of aks-preview. Please upgrade to the latest version of aks-preview like 20.0.0b1

Yes. it's working fine now with azure-cli 2.85.0-1~bookworm and a cleanup/upgrade of my az extensions.

Thanks for the fix.

Navigation Menu

Repository navigation

az aks start crash #33125

Describe the bug

Related command

Errors

Issue script & Debug output

Expected behavior

Environment Summary

Additional context

Solution 1:

Solution 2:

Solution 3:

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

az aks start crash #33125

Description

Describe the bug

Related command

Errors

Issue script & Debug output

Expected behavior

Environment Summary

Additional context

Activity

yonzhan commented on Apr 2, 2026

github-actions commented on Apr 2, 2026

Solution 1:

Solution 2:

Solution 3:

microsoft-github-policy-service commented on Apr 2, 2026

microsoft-github-policy-service commented on Apr 2, 2026

microsoft-github-policy-service commented on Apr 2, 2026

microsoft-github-policy-service commented on Apr 2, 2026

microsoft-github-policy-service commented on Apr 2, 2026

microsoft-github-policy-service commented on Apr 2, 2026

microsoft-github-policy-service commented on Apr 2, 2026

D2758695161 commented on Apr 2, 2026

FumingZhang commented on Apr 10, 2026

dod38fr commented on Apr 17, 2026

Metadata

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions