Re: Guix "ops"

[Ludovic Courtès]

Christopher Allan Webber <address@hidden> skribis:

> Ludovic Courtès writes:
>
>> Christopher Allan Webber <address@hidden> skribis:
>>
>>>  - Should I build the entire derivation of the system I want to run on
>>>    the remote machine locally first, then copy that over?  (I assume
>>>    this is possible, and eventually desirable, especially if doing
>>>    mass deployments?  But it might not be desirable in every case.)
>>>    Would that use the substitute mechanism?
>>
>> Yes!  :-)
>>
>> Essentially deployment would work like this:
>>
>>   1. Compute the system derivation and build it locally (i.e., on the
>>      machine where ‘guix deploy’ is running.)
>>
>>      As a user, you can choose to have offloading setup such that the
>>      actual build will take place on (some of) the target machines, but
>>      that’s completely orthogonal.
>>
>>   2. Send the derivation out to the target(s) that are real machines.
>>      For targets that are local containers or VMs, there’s nothing to
>>      do.
>>
>>   3. On targets that are real machines, perform the equivalent of ‘guix
>>      system reconfigure’—i.e., update the /run/current-system symlink,
>>      restart Shepherd services that can be restarted, etc.
>>
>> IIRC David was testing using VMs and containers as the targets (the
>> <platform> record¹) because it’s easier.
>>
>> Does that make sense?
>>
>> Hopefully David will correct me.  :-)
>
> Ok, it does make sense!
>
> It's nice to see the examples in the docs of exporting a system over
> ssh, even.  Anyway, I played with "guix archive" this morning; it works
> well.  So, sending an entire closure over the network: should be easy.
>
> I see that there's a --missing field; I'm a little bit unsure of how two
> machines would coordinate here though with the existing tooling... it
> doesn't look like we have a way to export the list of packges that
> --missing could then read in?  And then you'd need to feed whatever
> --missing gave you back into --export I guess.

Yes, there’s an example of that in (guix scripts offload), in
‘send-files’.

Essentially you do:

  guix archive --export \
    `guix gc -R the-thing-to-send | ssh host guix archive --missing` | \
    ssh host guix archive --import

HTH!

Ludo’.