Add ALL-IN operator to extra spec ops¶
Allow extra spec to match all values in a list by adding the ALL-IN operator.
This blueprint aims to allow querying if ALL of the given values are present in a list.
Currently there’s support for an IN operator that returns True if a given element is present in a list. There is also an OR operator that only works for single values.
Suppose operator or user want a flavor that will place VMs on a host that has the cpu flags ‘aes’ and ‘vmx’. As it is today is not possible since the only posibility is to use the <in> operator. But, as the extra specs is a dict, the flavor extra-spec key would be the same:
capabilities:cpu_info:features : <in> aes capabilities:cpu_info:features : <in> vmx
Just one of them will be saved.
Something like this is needed:
capabilities:cpu_info:features : <all-in> aes vmx
This blueprint doest’t fit into scheduler priorities for Kilo. It was accepted for Juno.
We need to add the new <all-in> operator and its lambda function to _op_methods dict in extra_specs_ops.py.
… ‘<all-in>’: lambda x, y: all(val in x for val in y), …
Then add a call to this function with a list, instead of with a string if there are more than one element in the query.
Instead of add the ‘<all-in>’ operator extend/overload the ‘<in>’ operator to work with a list.
capabilities:cpu_info:features : <in> aes vmx
Seems to be easy to understand but could generate confusion because <in> operator as it is today, aims to be used to match a substring.
Another possibility is add both <any> and <all> operators. By doing this, we are using <in> and <or> for single values and the new set of operators for collections values. But something is missing with this approach, <all> or <any> what? All elements in a list, all elements are True, or all elements are equal to a given value.
Data model impact¶
REST API impact¶
Other end user impact¶
Other deployer impact¶
Add a new lambda function to nova/scheduler/filter/extra_specs_ops.py _ops_method dict:
‘<all-in>’: lambda x, y: all(val in x for val in y)
- Primary assignee:
- Other contributors:
The change is simple and can be done in one Gerrit patch. Implementation is acutally completed.
Unit tests should be added for the new operator.
Filter scheduler documentation should be updated with the new operator.