Enabling Fernet tokens by default during Fuel installation


Implement Fernet tokens as default authentication method, including initial generation and propagation of keys to all controllers.

Problem description

The default Keystone configuration for Fernet tokens does not support keystone service running on multiple nodes. As a result, the current state requires Operators that are interested in using Fernet tokens to manually generate and sync the Fernet token key across controllers. Keystone itself does not have any knowledge of multiple key locations and does not provide any syncing capabilities natively. However, it is critical to have the keys synced between all Keystone nodes in order to provide token validation.

The goal of this spec is to provide a mechanism by which Fernet token keys can be easily generated, propagated during initial cluster environment setup to all keystone nodes and enabled by default.

Proposed changes

Keystone with Fernet tokens does not natively support multiple controllers, we propose to implement this functionality using astute and puppet manifests in fuel-library. This will enable the user to generate and install Fernet keys to all Keystone nodes seamlessly during the deployment process.

To generate keys, a new ‘GenerateFernetKeys’ class will be added to ‘pre-deployment actions’ of astute. It will use the openssl tool for key generation. The generated keys will be stored in the following directory on the Fuel-Master node:


To copy the generated Fernet keys to all controllers, a new ‘UploadFernetKeys’ class will be added to ‘pre-deployment actions’ of astute. It will copy Fernet keys to the following destination:


After copying Fernet keys to all controller nodes, they will be installed to the appropriate directory using puppets facilities:


In order to use Fernet tokens as the default authentication mechanism, the ‘token_provider’ Keystone parameter will be set to ‘keystone.token.providers.fernet.Provider’ in the associated puppet manifest.

Web UI




Data model



No FUEL REST API changes.



RPC Protocol


Fuel Client




Fuel Library

The following option should be passed to ::keystone class in order to enable Fernet tokens: * token_provider = keystone.token.providers.fernet.Provider


  • generate fernet keys using default keystone tool on Fuel Master node (keystone-manage fernet_setup) and copy them to all keystone nodes:

    This proposition was rejected as this case could lead to upgrade of Keystone on Fuel Master node. And it would require a large overhead cost to perform this update.

  • generate fernet keys using default keystone tool on Primary node (keystone-manage fernet_setup) where keystone service is running keystone service is running and copy them to another keystone nodes:

    This case was not implemented as there were some complexities to derive keys from deployed Primary node and copy the keys to another keystone node using Astute. This case needed an additional researching.

Upgrade impact

There should be no impact for Fuel Master upgrades. For existing cloud environment upgrades, there may be some service interruption until all controllers have been upgraded to support Fernet tokens and all tokens have been updated and all clients have new Fernet based tokens.

Security impact

It is expected to have the same security level as for ssh keys of mysql, nova and etc.

Notifications impact


End user impact


Performance impact

Rally run showed the following results:

Scenario Load durations(s) Full duration(s) Itera tions
  uuid fernet uuid fernet  
keystone 5000.27 5000.27 5154.19 5062.73 150000
create_and_list_tenants 2.761 3.189 23.574 25.295 30
create_and_list_users 4.004 4.401 17.392 22.203 90
create_delete_user 9.945 18.189 31.679 40.501 90
create_tenant_with_users 37.672 72.488 260.214 417.182 30
assign_and_removeuser_role 75.359 101.323 159.812 163.355 150
create_and_delete_role 16.571 20.585 23.143 29.165 150
create_and_delete_service 9.567 13.987 35.691 41.265 150
create_and_list_user_roles 11.924 17.279 16.250 22.469 150
get_entities 2.431 4.724 20.309 22.459 15
get_token 1.556 2.890 6.392 17.149 15
update_and_delete_tenant 12.583 17.237 18.141 25.379 150
update_user_password 18.320 16.987 42.551 41.364 150
boot_and_delete_server 269.515 311.886 297.314 347.193 300

Deployment impact


Developer impact


Infrastructure impact


Documentation impact

Switching to Fernet tokens and manual Fernet keys rotation procedure should be documented in Fuel Deployment Guide [1].



Primary assignee:
Maksym Yatsenko <myatsenko>
QA engineers:
Oleksandr Petrov <apetrov>
Mandatory design review:
Sergii Golovatiuk <sgolovatiuk> Vladimir Kuklin <vkuklin>

Work Items

  • Implement enabling Fernet tokens.
  • Perform fernet keys generation.
  • Copy Fernet keys to all keystone nodes during deployment process.



Testing, QA

Manual Acceptance Tests

  • Deploy HA-mode configuration
  • All keystone nodes should contain identical fernet keys

HA/Destructive Tests

  • Token verification after controller failure * issue a token * stop a controller this token was issued * make sure token works


Environment with enabled Fernet tokens should pass all tests currently run on Scale Lab with no significant performance degradation.

Acceptance criteria

After successfull deployment all keystone nodes contain identical fernet keys, Keystone functions properly.


[1]Fuel documentation