Re: How to add custom channels to ISO

[Elais Player <elais@fastmail.com>]

I don't know if it's something that should be put in the manual 
because I'm not really sure about the security implications of 
adding the channels file to the store. Though honestly I think its 
a neat solution because doing things this way you don't even have 
to create a =channels.scm= file. You can use the =scheme-file= 
procedure to just embed scheme code in a file like object and 
deliver it to the destination. Also when I asked on the IRC [1] 
ludo raised some concerns because there may be some issues with 
creating the =/etc/guix/= directory but I haven't run into any on 
three machines where I've done this.

Also glad I could help.

[1] https://logs.guix.gnu.org/guix/2020-12-04.log
phodina <phodina@protonmail.com> writes:

> Thanks Elais. This is exactly what I need.
>
> Also you're right regarding the ISO running out of space 
> (memory) as I ran =guix pull= once before the store was setup 
> and mounted on the target system.
>
> Also pinning the channels is useful to get "identical" os 
> installed across the machines.
>
> This might be a neat code excerpt and note in the manual 
> perhaps. Would you agree?
>
> Of course, once the system is setup then there is =guix deploy=.
>
>
>
>
> ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
>
> On Friday, July 30th, 2021 at 6:15 PM, Elais Player 
> <elais@fastmail.com> wrote:
>
>> You could add the custom channels file as an
>>
>> =extra-special-file=1 in the =os-configuration=.
>>
>> It would look something like this:
>>
>> #+BEGIN_SRC scheme
>>
>> (define %my-installation-os
>>
>> (operating-system
>>
>> (inherit installation-os)
>>
>> (services
>>
>> (cons*
>>
>> (extra-special-file
>>
>> "/etc/guix/channels.scm"
>>
>> (local-file "/path/to/my/channels.scm"))
>>
>> (operating-system-services installation-os)))))
>>
>> #+END_SRC
>>
>> Plus side is you now have a global channels file from which all
>>
>> you need to do is run =guix pull= to have all your channels up 
>> to
>>
>> date. You may also want to pin those channels to certain 
>> commits
>>
>> just in case. Down side is running =guix pull= will start 
>> filling
>>
>> up your disk or memory on an ISO and you can easily run out of
>>
>> space. (I would advise not running =guix pull= until after
>>
>> partitioning and setting up the target system), and this file 
>> will
>>
>> be added to the store (but if you're creating a channels file 
>> in
>>
>> =/etc= shouldn't matter honestly).
>>
>> phodina via help-guix@gnu.org writes:
>>
>> > Hello,
>> >
>> > I'm migrating to a newer machine and I'm taking my GuixSD
>> >
>> > configuration with me.
>> >
>> > So the first logical step I did was to create an ISO image 
>> > based
>> >
>> > on this section 1. As I use my custom channel with modified
>> >
>> > packages I added them to the configuration to make them
>> >
>> > available on the new machine.
>> >
>> > Or so I thought. I booted and partitioned the new machine 
>> > then
>> >
>> > ran
>> >
>> > guix system init /root/configurations.scm /mnt to install 
>> > Guix
>> >
>> > there.
>> >
>> > However, after reboot turns out that the packages are not 
>> > from
>> >
>> > my channel but from public Guix repository without
>> >
>> > modifications.
>> >
>> > Therefore my question is if it's possible to specify also
>> >
>> > channels in the configuration file so that they are used 
>> > during
>> >
>> > installation?
>> >
>> > Reading the manual I came to a nice command guix system 
>> > describe
>> >
>> > 2 which gives me the current configuration with the
>> >
>> > channels. Could that be used to build an ISO which would then
>> >
>> > also know about the additional channels?
>> >
>> > Kind regards
>> >
>> > Petr