/run/booted-system is not protected from GC. Here’s what I observed on a machine with unattended upgrades (which includes automatic removal of old system generations):
--8<---------------cut here---------------start------------->8--- ~$ ls -l /run/booted-system lrwxrwxrwx 1 root root 33 Nov 2 16:06 /run/booted-system -> /var/guix/profiles/system-68-link ~$ ls -l /var/guix/profiles/system-68-link ls: cannot access '/var/guix/profiles/system-68-link': No such file or directory ~$ ls -lrt /var/guix/profiles/system-*-link lrwxrwxrwx 1 root root 50 Nov 29 01:34 /var/guix/profiles/system-74-link -> /gnu/store/ym7bs9pp9lxy0s1pjfrbic0pjjr7svzd-system lrwxrwxrwx 1 root root 50 Dec 6 01:33 /var/guix/profiles/system-75-link -> /gnu/store/ivxak4d58gqz2xqihkc636nhwhpa1fs4-system lrwxrwxrwx 1 root root 50 Dec 13 01:35 /var/guix/profiles/system-76-link -> /gnu/store/wqpwlqlfsc4yqm0nypzvan1a8sb9xmcc-system lrwxrwxrwx 1 root root 50 Dec 27 01:33 /var/guix/profiles/system-77-link -> /gnu/store/y539xw934mbdcqidg6zaxrzq9hy8hm9p-system lrwxrwxrwx 1 root root 50 Jan 4 09:29 /var/guix/profiles/system-78-link -> /gnu/store/3582jh1v9vn51wasyl1y189ng4vhqiy9-system lrwxrwxrwx 1 root root 50 Jan 10 01:33 /var/guix/profiles/system-79-link -> /gnu/store/q67avpz4bfhq2zyfhh8ka6q9hpqzc3xj-system lrwxrwxrwx 1 root root 50 Jan 17 01:33 /var/guix/profiles/system-80-link -> /gnu/store/13bwrvjgsl16sigwpa93yr4r51qnm8zi-system lrwxrwxrwx 1 root root 50 Jan 19 14:23 /var/guix/profiles/system-81-link -> /gnu/store/v151wf6lj4ivgj3xwysi9fdmva55jzqp-system lrwxrwxrwx 1 root root 50 Jan 24 01:35 /var/guix/profiles/system-82-link -> /gnu/store/rvarwdsymd94am8bc8b1rx2xdrxcvx6l-system lrwxrwxrwx 1 root root 50 Jan 31 01:33 /var/guix/profiles/system-83-link -> /gnu/store/0sgd2yb702483zi3hl04wv4r4rn3ibcy-system lrwxrwxrwx 1 root root 50 Feb 7 01:32 /var/guix/profiles/system-84-link -> /gnu/store/bix4yp9zs2h3vy8zi9ap9mazap727hng-system lrwxrwxrwx 1 root root 50 Feb 14 01:33 /var/guix/profiles/system-85-link -> /gnu/store/702l59w3gbsc45c7nffsyv89vnaky5zc-system lrwxrwxrwx 1 root root 50 Feb 21 01:34 /var/guix/profiles/system-86-link -> /gnu/store/qq4rz2fprvnsgqhj24v735hhmp189jl8-system --8<---------------cut here---------------end--------------->8--- This is bad but mostly harmless since all the packages actually in use are GC-protected anyway, via ‘guix gc --list-busy’. It breaks things like ‘guix deploy’ though. Specifically, its remote initrd module check in (gnu machine ssh) looks for /run/booted-system/kernel/lib/modules/KERNEL-VERSION/modules.alias, via ‘missing-modules’ of (gnu build linux-modules). That code throws because ‘modules.alias’ is supposed to exist, which in turn leads ‘guix deploy’ to crash badly: --8<---------------cut here---------------start------------->8--- $ guix time-machine -C channels.scm -- deploy deploy.scm The following 1 machine will be deployed: guix-hpc guix deploy: deploying to guix-hpc... substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0% La jenaj derivoj estos konstruataj: /gnu/store/nh0n44vb4i445msj6g6i0kwyp3jgs39c-remote-exp.scm.drv /gnu/store/44271p6fvygx0fa7dvjhmqz7jwnnr9sc-remote-assertion.scm.drv /gnu/store/5nqzxyal9lhhga7bz9qf6hvml5v862xw-remote-assertion.scm.drv 0.0 MB will be downloaded downloading from https://ci.guix.gnu.org/nar/lzip/1q9118pw4d18ihj91csfilbg6x2x29am-module-import-compiled ... module-import-compiled 8KiB 1.7MiB/s 00:00 [##################] 100.0% building /gnu/store/44271p6fvygx0fa7dvjhmqz7jwnnr9sc-remote-assertion.scm.drv... building /gnu/store/5nqzxyal9lhhga7bz9qf6hvml5v862xw-remote-assertion.scm.drv... building /gnu/store/nh0n44vb4i445msj6g6i0kwyp3jgs39c-remote-exp.scm.drv... guix deploy: sending 8 store items (5 MiB) to 'localhost'... FORMAT: error with call: (format #f "missing modules for ~a:~{ ~a~}<===~%" #<file-system-label "root"> ===>#f ) expected a list argument FORMAT: INTERNAL ERROR IN FORMAT-ERROR! destination: #f format string: "missing modules for ~a:~{ ~a~}~%" format args: (#<file-system-label "root"> #f) error args: (#f "error in format" () #f) Backtrace: In guix/store.scm: 1305:8 19 (call-with-build-handler #<procedure 7f0d3cc35240 at guix/ui.scm:1171:2 (continue store things mode)> _) In guix/scripts/deploy.scm: 170:14 18 (_) In guix/store.scm: 1346:2 17 (map/accumulate-builds #<store-connection 256.99 7f0d39c6c000> _ _) In srfi/srfi-1.scm: 586:17 16 (map1 (#<<unresolved> things: (("/gnu/store/b5nnbpgkvgdpzgvj67539ylcaqacj90l-guile-3.0.2.drv" . "out"…>)) In guix/store.scm: 1305:8 15 (call-with-build-handler #<procedure build-accumulator (continue store things mode)> _) In ice-9/boot-9.scm: 1736:10 14 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _) In guix/scripts/deploy.scm: 144:6 13 (_) In guix/store.scm: 2066:24 12 (run-with-store #<store-connection 256.99 7f0d39c6c000> _ #:guile-for-build _ #:system _ #:target _) In gnu/machine/ssh.scm: 445:2 11 (_ _) 338:4 10 (_ _) In srfi/srfi-1.scm: 650:11 9 (for-each #<procedure 7f0d3e372d28 at gnu/machine/ssh.scm:338:14 (proc value)> _ _) In gnu/machine/ssh.scm: 275:26 8 (_ #f) In ice-9/format.scm: 1546:2 7 (format #f "missing modules for ~a:~{ ~a~}~%" #<file-system-label "root"> #f) 571:24 6 (format:format-work "missing modules for ~a:~{ ~a~}~%" (#<file-system-label "root"> #f)) In ice-9/boot-9.scm: 1736:10 5 (with-exception-handler _ _ #:unwind? _ #:unwind-for-type _) In ice-9/format.scm: 102:10 4 (_) In ice-9/boot-9.scm: 1669:16 3 (raise-exception _ #:continuable? _) 1669:16 2 (raise-exception _ #:continuable? _) 1669:16 1 (raise-exception _ #:continuable? _) 1669:16 0 (raise-exception _ #:continuable? _) ice-9/boot-9.scm:1669:16: In procedure raise-exception: error in format --8<---------------cut here---------------end--------------->8--- Ludo’.
