[openstack-dev] [keystone] Token providers and Fernet as the default
clint at fewbar.com
Tue May 3 16:51:52 UTC 2016
Excerpts from Adam Young's message of 2016-05-03 07:21:52 -0700:
> On 05/03/2016 09:55 AM, Clint Byrum wrote:
> > When the operator has configured a new token format to emit, they should
> > also be able to allow any previously emitted formats to be validated to
> > allow users a smooth transition to the new format. We can then make the
> > default behavior for one release cycle to emit Fernet, and honor both
> > Fernet and UUID.
> > Perhaps ignore the other bit that I put in there about switching formats
> > just because you have fernet keys. Let's say the new pseudo code only
> > happens in validation:
> > try:
> > self._validate_fernet_token()
> > except NotAFernetToken:
> > self._validate_uuid_token()
> I was actually thinking of a different migration strategy, exactly the
> opposite: for a while, run with the uuid tokens, but store the Fernet
> body. After while, switch from validating the uuid token body to the
> stored Fernet. Finally, switch to validating the Fernet token from the
> request. That way, we always have only one token provider, and the
> migration can happen step by step.
> It will not help someone that migrates from Icehouse to Ocata. Then
> again, the dual plan you laid out above will not either; at some point,
> people will have to dump the token table to make major migrations.
Your plan has a nice aspect that it allows validating Fernet tokens on
UUID-configured nodes too, which means operators don't have to be careful
to update all nodes at one time. So I think what you describe above is
an even better plan.
Either way, the point is to avoid an immediate mass token invalidation
event on change of provider.
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