Updating a DNSSEC config to use a different algorithm

[@lbutlr]

On 02 Feb 2021, at 02:23, Matthijs Mekking <matthijs at isc.org> wrote:
> 1. Create a dnssec-policy that matches your current keys (so in your case algorithm 7, also make sure you use the same length).
> 
> So I guess something like:
> 
>    dnssec-policy alg13-ksk-unlimited-zsk-60day {
>        keys {
>            ksk key-directory lifetime unlimited algorithm 7 2048;
>            zsk key-directory lifetime P60D algorithm 7 1024 ;
>        };
>    };
> 
> This is an assumption. Check the key length with your existing keys.

Yes, the current keys are alg 7 2048 bit. Is there a document on the various options here? I am plowing through the "BIND 9 Administrator Reference Manual, Release BIND 9.16.5 (Stable Release)" but it is slow going right now and "dnssec-policy" does not appear in the pdf in a searchable form, which makes things even more fun).

(This domain has a RRSIG range of 20210122220953 - 20210221230953) 

I am guessing as soon as I add that DNSSEC-policy I also need to change each domain record from "auto-dnssec maintain;" to "dnssec-policy default;" or do I do that after the .state files have been created? (That doesn't sound right, but best to check).

> Now that you have migrated your existing key files (they will now have a .state file), you can reconfigure your dnssec-policy with a new algorithm,. The alg-7 keys will be gracefully removed from the zone, while new keys with a new algorithm will be introduced.

So once all the domains have a .state file associated with them in the key directory I can change the dnssec-policy to the sample I had before and it will just migrate from the alg 7 keys above to alg ECDSAP256SHA256 (or I can just say alg 13 instead).

#v+
dnssec-policy alg13-ksk-unlimited-zsk-60day {
    keys {
        ksk key-directory lifetime unlimited algorithm 13;
        zsk key-directory lifetime P60D algorithm 13;
    };
};
#v-

That seems very straightforward, there must be a catch somewhere.

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