Ubuntu installation: preseed late_command fails

[Vladimir Kozhukalov]

VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "6.1"
  api: "1.0"
  build_number: "205"
  build_id: "2015-03-18_11-17-17"
  nailgun_sha: "b30621920d9fadff6b13981bec98f57c69181ed4"
  python-fuelclient_sha: "9917b2eab41c27375719d6a311884339b2e2da11"
  astute_sha: "8b8b2681b6bdec07b091aacbf15b90d0f0593cfe"
  fuellib_sha: "de7ea04ef1a8b8399949d1ad28c6ac29d2b3e084"
  ostf_sha: "6727353aa4c9f83be2508d123ccde41cba72b1cb"
  fuelmain_sha: "188e6536bfbe31a297be9c8c327f0b127eeca6d8"

Ubuntu installing freezes on "Finish the installation" stage and shows purple user menu. See below log tail

/var/log/remove/node-X/finish-install.log
2015-03-18T18:09:54.594715+00:00 notice: info: Running /usr/lib/finish-install.d/01kickseed
2015-03-18T18:09:54.603178+00:00 notice: info: Running /usr/lib/finish-install.d/05localechooser
2015-03-18T18:09:54.607382+00:00 notice: info: Running /usr/lib/finish-install.d/06user-setup
2015-03-18T18:09:54.615349+00:00 notice: warning: /usr/lib/finish-install.d/06user-setup returned error code 127
2015-03-18T18:09:54.617132+00:00 notice: info: Running /usr/lib/finish-install.d/07brltty
2015-03-18T18:09:54.624490+00:00 notice: info: Running /usr/lib/finish-install.d/07preseed
2015-03-18T18:09:54.655694+00:00 notice: /bin/preseed_command:
2015-03-18T18:09:54.658803+00:00 notice: return:
2015-03-18T18:09:54.658803+00:00 notice: line 23:
2015-03-18T18:09:54.658827+00:00 notice: Illegal number: "
2015-03-18T18:09:54.658827+00:00 notice:
2015-03-18T18:09:54.659429+00:00 notice: warning: /usr/lib/finish-install.d/07preseed returned error code 2
2015-03-18T18:09:54.661073+00:00 notice: info: Running /usr/lib/finish-install.d/07speakup

[Vladimir Kozhukalov (kozhukalov)]

It turned out that the reason for this error to appear was the absence of /dev/disk/by-id link because I used QEMU+virtio disk without additional tags like serial or wwn.