$ guix system reconfigure $HOME/dotfiles/guix/system-magnolia.scm

substitute: updating list of substitutes from 'https://berlin.guixsd.org'... 100.0%
The following derivations will be built:
   /gnu/store/v9dp6193rpxrx1rqfdw59s5ss4wlrfdh-system.drv
   /gnu/store/carkycnf6zcarbmnk5745pgsx1nv478y-grub.cfg.drv
   /gnu/store/r5p953fx3dl18aav1ggwmiy2bqnv991s-activate-service.drv
   /gnu/store/pjjm6595562ysk40zjrznhmsfsid1k8r-activate.drv
   /gnu/store/l41adszqk24sb200dwm8sj6ky71ivwpi-boot.drv
/gnu/store/qqhzapsv5w8mrbz3s8hgy7w42r3dbyv9-system
/gnu/store/b4i4drp7lpxmgpcfkbvgmrig2hlszl3j-grub.cfg
/gnu/store/0b459jxdmyz5vf22avav9sm8ig03173k-grub-efi-2.02
/gnu/store/ijw065yljn1np4x0p5l1qkx9w4z9ikcl-bootloader-installer
activating system...
making '/gnu/store/qqhzapsv5w8mrbz3s8hgy7w42r3dbyv9-system' the current system...
setting up setuid programs in '/run/setuid-programs'...
populating /etc from /gnu/store/iyr9ji3idg3iphi3fskh2hqjlmg4h5w0-etc...
usermod: no changes
adding group 'test'...
groupadd: existing lock file /etc/group.lock without a PID
groupadd: cannot lock /etc/group; try again later.
usermod: no changes
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: no changes
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: existing lock file /etc/group.lock without a PID
usermod: cannot lock /etc/group; try again later.
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
usermod: no changes
creating nginx log directory '/var/log/nginx'
creating nginx run directory '/var/run/nginx'
creating nginx temp directories '/var/run/nginx/{client_body,proxy,fastcgi,uwsgi,scgi}_temp'
nginx: [alert] could not open error log file: open() "/gnu/store/vyj2vkmdmlpxn3mnj71vz8zc8j30ahkf-nginx-1.12.1/logs/error.log" failed (2: No such file or directory)
nginx: the configuration file /gnu/store/xms1g2z62rcj2h9i9d6fbqyl65a4yycm-nginx.conf syntax is ok
nginx: configuration file /gnu/store/xms1g2z62rcj2h9i9d6fbqyl65a4yycm-nginx.conf test is successful
guix system: unloading service 'user-homes'...
shepherd: Removing service 'user-homes'...
shepherd: Done.
guix system: loading new services: user-homes...
shepherd: Evaluating user expression (register-services (primitive-load "/gnu/sto?")).
shepherd: Service user-homes could not be started.
Installing for x86_64-efi platform.
Installation finished. No error reported.