(In reply to Alexander Chuzhoy from comment #0)
> roles_data.yaml must include "subnet:"  under each network for a role.  This
> can affect upgrade from previous release.
> 
> Environment:
> openstack-tripleo-heat-templates-10.6.1-0.20190722170519.014b20c.el8ost.
> noarch
> 
> Here's an example of networks for the default controller role:
> - name: Controller
>   description: |
>     Controller role that has all the controler services loaded and handles
>     Database, Messaging and Network functions.
>   CountDefault: 1
>   tags:
>     - primary
>     - controller
>   networks:
>     External:
>       subnet: external_subnet
>     InternalApi:
>       subnet: internal_api_subnet
>     Storage:
>       subnet: storage_subnet
>     StorageMgmt:
>       subnet: storage_mgmt_subnet
>     Tenant:
>       subnet: tenant_subnet
> 
> 

This should not be a problem, prior to adding subnets the 'networks' of a role contained a list of network names, for example:

  networks:
    - External
    - InternalApi
    - Storage
    - StorageMgmt
    - Tenant

We have contition's checking if role.networks is a mapping or not already. If the role data from a previous release is used it would be a list and we fall-back to use {{network.name_lower}}_subnet.
A few examples where we ensure to support both the new and old format:
 https://github.com/openstack/tripleo-heat-templates/blob/master/puppet/role.role.j2.yaml#L425-L434
 https://github.com/openstack/tripleo-heat-templates/blob/9119734f0adec3bfd41f5f4a50f08a8cb8610968/environments/network-isolation.j2.yaml#L23-L32
 https://github.com/openstack/tripleo-heat-templates/search?q=%22if+role.networks+is+mapping%22&unscoped_q=%22if+role.networks+is+mapping%22


> A deployment will fail during validation if the subnets are commented out.
> This can affect upgrades from previous releases where subnets weren't set.

I was'nt aware of this validation, can you share more details such as the exact validation error so I may find that pice of validation code?
IMO it's not a bad idea to do such validation, and halt the deployment so that we may remove all that compatiblity code in a feature release. But the error should be clear about it, and we need to document it.

Sasha, do you have the output from when the validation failed? The actual error message would be helpful here.

Just removed the subnets from controller role:

(undercloud) [stack@undercloud-0 ~]$ diff templates/roles_data.yaml{,_orig}                                                                                                                   
16a17
>       subnet: external_subnet
17a19
>       subnet: internal_api_subnet
18a21
>       subnet: storage_subnet
19a23
>       subnet: storage_mgmt_subnet
20a25
>       subnet: tenant_subnet




(undercloud) [stack@undercloud-0 ~]$ bash overcloud_deploy.sh
Removing the current plan files
Uploading new plan files
Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'
{'result': "Failure caused by error in tasks: notify_zaqar\n\n  notify_zaqar [task_ex_id=2e3cd0ab-06f8-4b17-8607-587bb1ac4d50] -> Workflow failed due to message status. Status:FAILED Message:Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'\n    [wf_ex_id=a0118a77-38e0-4d9f-b801-b6837a2c0ef5, idx=0]: Workflow failed due to message status. Status:FAILED Message:Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'\n", 'swift_container': 'overcloud-swift-rings', 'status': 'FAILED', 'message': "Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'"}
Exception updating plan: {'result': "Failure caused by error in tasks: notify_zaqar\n\n  notify_zaqar [task_ex_id=2e3cd0ab-06f8-4b17-8607-587bb1ac4d50] -> Workflow failed due to message status. Status:FAILED Message:Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'\n    [wf_ex_id=a0118a77-38e0-4d9f-b801-b6837a2c0ef5, idx=0]: Workflow failed due to message status. Status:FAILED Message:Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'\n", 'swift_container': 'overcloud-swift-rings', 'status': 'FAILED', 'message': "Error rendering template puppet/controller-role.yaml : 'None' has no attribute 'get'"}

(In reply to Alexander Chuzhoy from comment #7)
> Just removed the subnets from controller role:
> 
> (undercloud) [stack@undercloud-0 ~]$ diff templates/roles_data.yaml{,_orig} 
> 
> 16a17
> >       subnet: external_subnet
> 17a19
> >       subnet: internal_api_subnet
> 18a21
> >       subnet: storage_subnet
> 19a23
> >       subnet: storage_mgmt_subnet
> 20a25
> >       subnet: tenant_subnet


Sasha, what did your role_data.yaml networks section look like? I would expect this:

  networks:
    - External
    - InternalApi
    - Storage
    - StorageMgmt
    - Tenant

But if the only difference was the missing subnet: lines, does that mean that it actually looks like this?

  networks:
    - External:
    - InternalApi:
    - Storage:
    - StorageMgmt:
    - Tenant:

That seems to be the only logical conclusion if the only difference was the missing "subnet: <network>_subnet" lines.

Thanks for looking into it Dan,
I indeed forgot to remove the colons. Once removed - the deployment proceeds.
Closing as not a bug.