It's possible to assign role(s) to a node that can't meet default disk allocation minimums

[Andrew Woodward]

When assigning roles, its possible to assign one or more roles that cant satisfy the default disk allocations.

steps to reproduce
1. create a 20gb disk VM
2. discover the vm
3. allocate the VM to controller and cinder iscsi roles

expected result
node role combo should raise an exception that is given to the user and added role should not be saved.

actual result.
Node is successfully assigned role(s) in the cluster

Node can be deployed with the bad disk space

[Vladimir Sharshov (vsharshov)]

Looks like this bug covered by blueprint: https://blueprints.launchpad.net/fuel/+spec/volume-manager-refactoring. Move it to 8.0 after discuss with Alexander Gordeev.

Feel free to return and up priority if do not agree.

[Evgeniy L (rustyrobot)]

Basically it has nothing to do with volume manager, validation when role is changed should be added, also UI should be fixed in order to show it in user friendly way.

[Alexander Kislitsky (akislitsky)]

We passed SCF in 8.0. Moving the bug to 9.0.

[Dmitry Pyzhov (dpyzhov)]

We don't backport medium bugs