879769 - imaging processes should not regenerate SSH host keys

Status: RESOLVED WONTFIX

(Infrastructure & Operations :: RelOps: Puppet, task)

Description

[Dustin J. Mitchell [:dustin] (he/him)]

I've been reimaging bld-lion-r5-003 recently, and just realized I haven't gotten any warnings about the host key, because it's not changing.

Aside from a few edge cases (e.g., multiple hosts in a pool accepting ssh connections), every host should have a different host key.  So this should be fixed in the imaging process.

Comment 1

[Amy Rich [:arr] [:arich]]

I don't so much care if all hosts have different host keys, but each host should keep the *same* host key through a reimage.

Comment 2

[Dustin J. Mitchell [:dustin] (he/him)]

Joe?  There's some convenience to having hosts keep the same key, and the only practical way to accomplish that is for all hosts to have the same single key.

Comment 3

[Amy Rich [:arr] [:arich]]

Or to store the keys in a db of some sort and have them reloaded onto the machine after each image.

Comment 4

[Dustin J. Mitchell [:dustin] (he/him)]

I'd be leery of storing a whole pile of private keys in one database.

Comment 5

[Dustin J. Mitchell [:dustin] (he/him)]

Per :kang, a single host key across the pool is the best solution.

So, we should fix a pub/pvt key pair at whatever level of granularity is easiest, and install it.  We should do that with puppet, since this should *not* apply to non-slaves.

Comment 6

[Dustin J. Mitchell [:dustin] (he/him)]

I think that the design would be to add a slave_ssh_host_key/slave_ssh_host_key_pub secret pair, and if those are nonempty, set them when puppet runs, but only on slaves.

Not a high priority, so I'm unassigning from myself.

Comment 7

[Dustin J. Mitchell [:dustin] (he/him)]

I think this is moot in the era of images.