[Freeipa-devel] DNSSEC: upgrade path to Vault

[Petr Spacek]

On 10.3.2014 12:08, Martin Kosek wrote:
> On 03/10/2014 11:49 AM, Petr Spacek wrote:
>> On 7.3.2014 17:33, Dmitri Pal wrote:
>>> I do not think it is the right architectural approach to try to fix a specific
>>> use case with one off solution while we already know that we need a key storage.
>>> I would rather do things right and reusable than jam them into the currently
>>> proposed release boundaries.
>> I want to make clear that I'm not opposed to Vault in general. I'm questioning
>> the necessity of Vault from the beginning because it will delay DNSSEC
>> significantly.
>
> +1, I also now see number of scenarios where Vault will be needed.
>
>>
>> One of the proposals in this thread is to use something simple for DNSSEC keys
>> (with few lines of Python code) and migrate DNSSEC with Vault when Vault is
>> available and stable enough (in some later release).
>>
>>> I understand that Vault brings a lot of work to the table. But let us do it
>>> right and if it does not fit into 4.0 let us do it in 4.1.
>> We will have one huge release with DNSSEC + Vault at once if we to postpone
>> DNSSEC to the same release as Vault.
>>
>> As a result, it would be harder to debug it because we will have to find if
>> something is broken because of:
>> - DNSSEC-IPA integration
>> - Vault-IPA integration
>> - DNSSEC-Vault integration.
>>
>> I don't think it is a good idea to make such huge release.
>>
>> "Release early, release often"
>>
>
> I must say I tend to agree with Petr. If the "poor man's solution" of DNSSEC
> without Vault does not cost us too much time and it would seem that the Vault
> is not going to squeeze in 4.0 deadlines, I would rather release the poor man's
> solution in 4.0 and switch to Vault when it's available in 4.1.
>
> This would let our users test the non-Vault parts of our DNSSEC solution
> instead of waiting to test a perfect solution.

Yesterday we have agreed that DNSSEC support is not going to depend on Vault 
from the beginning and that we can migrate to Vault later.

Here I'm proposing safe upgrade path from non-vault to Vault solution.

After all, it seems relatively easy.

TL;DR version
=============
Use information in cn=masters to detect if there are old replicas and 
temporarily convert new keys from Vault to LDAP storage (until all old 
replicas are deleted).

Full version
============
IPA 4.0 is going to have OpenDNSSEC key generator on a single IPA server and 
separate key import/export daemon (i.e. script called from cron or something 
like that) on all IPA servers.

In 4.0, we can add new LDAP objects for DNSSEC-related IPA services (please 
propose better names :-):
- key generator:
cn=OpenDNSSECv1,cn=vm.example.com,cn=masters,cn=ipa,cn=etc,dc=ipa,dc=example

- key imported/exporter:
cn=DNSSECKeyImporterv1,cn=vm.example.com,cn=masters,cn=ipa,cn=etc,dc=ipa,dc=example


Initial state before upgrade:
- N IPA 4.0 replicas
- N DNSSECKeyImporterv1 service instances (i.e. key distribution for IPA 4.0)
- 1 OpenDNSSECv1 service instance (key generator)

Now we want to upgrade a first replica to IPA 4.1. For simplicity, let's add a 
*requirement* to upgrade the replica with OpenDNSSECv1 first. (We can 
generalize the procedure if this requirement is not acceptable.)

Upgrade procedure:
- stop OpenDNSSECv1 service
- stop DNSSECKeyImporterv1 service
- convert OpenDNSSECv1 database to OpenDNSSECv2
This step is not related to Vault. We need to covert local SQLite database 
from single-node OpenDNSSEC to LDAP-backed distributed OpenDNSSEC.

- convert private keys from LDAP to Vault *but let them in LDAP for a while*.
- walk through cn=masters,cn=ipa,cn=etc,dc=ipa,dc=example and check if there 
are any other replicas with DNSSECKeyImporterv1 service:
a) No such replica exists -> delete old-fashioned keys from LDAP.
b) Another replica with DNSSECKeyImporterv1 service exists:
- *Temporarily* run DNSSECKeyImporterv2 which will do one-way key conversion 
from Vault to LDAP.
- DNSSECKeyImporterv2 can check e.g. daily if all DNSSECKeyImporterv1 
instances were deleted or not. Then it can delete old-fashioned keys from LDAP 
and also stop itself when all old replicas were deleted (and compatibility 
mode is not needed anymore).

This approach removes time constraints from upgrade procedure and prevents DNS 
servers from failing when update is delayed etc. As a result, admin can 
upgrade replica-by-replica at will.

-- 
Petr^2 Spacek