nova.compute.api.create don't validate max_count is a valid number

[Nachi Ueno]

nova.compute.api.create don't validate max_count is a valid number or not.
When the user input a string value as max_count, then nova.compute creates max quota number of instances .

[Mark McLoughlin (markmc)]

Moving from InProgress to Confirmed since nobody is assigned

[shanthkumar khandre (shanthkumar09)]

Hi all,

I have used the following code to reproduce the bug.

from novaclient.v1_1 import client
from os import environ as env
nt = client.Client(env['NOVA_USERNAME'], env['NOVA_API_KEY'],
env['NOVA_PROJECT_ID'], env['NOVA_URL'])
nt.servers.create("name4","c0b242ce-0b7c-4b18-b42b-0275c847b968",1, max_count="20")

It succeeded and max_quota number of instances are created if max_count is greater than the max_quota.

if max_count > num_instances:
    raise exception.QuotaError(code="InstanceLimitExceeded")

The above condition is added in def _create_instance method of compute.api file to validate the max count.

num_instances = quota.allowed_instances(context, max_count,
                                                instance_type) (add the above condition after this line)

If the above code is executed, then the following error will be produced.

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/dist-packages/novaclient/v1_1/servers.py", line 430, in create
    **boot_kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/v1_1/base.py", line 153, in _boot
    return_raw=return_raw, **kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/base.py", line 147, in _create
    resp, body = self.api.client.post(url, body=body)
  File "/usr/lib/python2.7/dist-packages/novaclient/client.py", line 137, in post
    return self._cs_request(url, 'POST', **kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/client.py", line 122, in _cs_request
    **kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/client.py", line 105, in request
    raise exceptions.from_response(resp, body)
novaclient.exceptions.OverLimit: Quota exceeded: code=%(code)s (HTTP 413)

But when a string value is passed in max_count (max_count = "any_string") following exception is thrown:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/dist-packages/novaclient/v1_1/servers.py", line 430, in create
    **boot_kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/v1_1/base.py", line 153, in _boot
    return_raw=return_raw, **kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/base.py", line 147, in _create
    resp, body = self.api.client.post(url, body=body)
  File "/usr/lib/python2.7/dist-packages/novaclient/client.py", line 137, in post
    return self._cs_request(url, 'POST', **kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/client.py", line 122, in _cs_request
    **kwargs)
  File "/usr/lib/python2.7/dist-packages/novaclient/client.py", line 105, in request
    raise exceptions.from_response(resp, body)
novaclient.exceptions.ClientException: The server has either erred or is incapable of performing the requested operation. (HTTP 500)

Please let me know if there are any comments on the same.

[shanthkumar khandre (shanthkumar09)]

Hi,

I have used the following code to reproduce the bug.
(max_quota is 10 in my environment.)

from novaclient.v1_1 import client
from os import environ as env
nt = client.Client(env['NOVA_USERNAME'], env['NOVA_API_KEY'],
env['NOVA_PROJECT_ID'], env['NOVA_URL'])
nt.servers.create("name4","c0b242ce-0b7c-4b18-b42b-0275c847b968",1, max_count="20")

From the above, user tries to create 20 instances and it got succeded and only max_quota number
of instances created. But user will think that 20 instances got created.

For example if already 5 instances are existing then if we execute the above command it creates only
5 instances. But user might think that 10 instances got created. Thats the reason i am checking the
below condition and throwing the exception(Quota exceeded) if max_count value is greater than the
num_instances i.e., allowed_instances.

if max_count > num_instances:
    raise exception.QuotaError(code="InstanceLimitExceeded")

Please let me know if there are any comments on the same.

[Brian Waldon (bcwaldon)]

max_count is not the number of requested instances, it is the *maximum* number of instances you would like created. The lower bound defaults to 1, so asking for a max of 20 will get you anywhere from 1 to 20. If you want a specific number of instances greater than 1, you will need to specify both max_cound AND min_count. Test that out and see if you get the expected behavior.

[shanthkumar khandre (shanthkumar09)]

I have tested by passing both min_count(20) and max_count(20), then its throwing an exception (Quota exceeded).
Because min_count value is greater than the max_quota(10).

I have tested by passing string value in max_count("2s") then its throwing an exception as expected. But when
I pass integer value in string like max_count="2", its validating and only those many instances got created.

Eg. nt.servers.create("name4","47b2171b-61e5-4ffc-877f-99e6c00ae53f",1,max_count="2")
Only 2 instances got created.
So marking the bug as invalid.