On 11.3.2014 12:21, Martin Kosek wrote:
On 03/11/2014 11:33 AM, Petr Spacek wrote:
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

cn=DNSSEC,cn=vm.example.com,cn=masters,cn=ipa,cn=etc,dc=ipa,dc=example

DNSSEC will be translated by FreeIPA to appropriate service name. This can vary
between platforms. "v1" can be an attribute of the entry, I would not add it's
to name.

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

I am thinking it may be sufficient to have just:

cn=DNSSEC,cn=vm.example.com,cn=masters,cn=ipa,cn=etc,dc=ipa,dc=example

for all DNSSEC empowered masters and then just have:
ipaConfigString: keygenerator

... in the master VM. I am just trying to be future agnostic and avoid
hardcoding service names and implementations details in cn=masters. FreeIPA on
master would know what services to run when it is a keygenerator or not.

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:

In my proposal, one would just search for "cn=DNSSEC,cn=*,cn=masters..." with
filter "(ipaConfigString=version 1)".
Why not :-) I do not care as long as it is unambiguous.

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.

Ok, though I am a little bit afraid that the temporary solution would become a
permanent solution. There would need to be something forcing and pushing admins
to migrate.

Could you be more specific? Is there any particular difference from any other IPA upgrade?

We always tell users to upgrade soon:
It is expected
that all servers will be upgraded in a relatively short period (days or weeks,
not months). They should be able to co-exist peacefully but new features will
not be available on old servers  [...]

IMHO the key is in "new features will not be available on old servers". In this case the "new feature" is "no single point of failure" which seems pretty important to me :-)

--
Petr^2 Spacek

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