libs check turns yellow if no kernel image exists

[Andreas Oberritter]

If there's no kernel image installed, e.g. in an LXC environment, then the following output gets generated. This didn't happen in 14.04 LTS.

Thu Jan 14 16:00:37 2016 - libs NOT ok

yellow Warning: Use of uninitialized value $newest_kernel_image in pattern match (m//) at /usr/lib/xymon/client/ext/libs line 66.
yellow Warning: Use of uninitialized value $newest_kernel_image in concatenation (.) or string at /usr/lib/xymon/client/ext/libs line 69.
yellow Warning: Use of uninitialized value $kernel_image_release in concatenation (.) or string at /usr/lib/xymon/client/ext/libs line 74.
yellow Warning: Use of uninitialized value $newest_kernel_image in -r at /usr/lib/xymon/client/ext/libs line 86.
yellow Warning: Use of uninitialized value $newest_kernel_image in concatenation (.) or string at /usr/lib/xymon/client/ext/libs line 87.
yellow Kernel image unreadable. Can't check kernel version!
See comment #3 on https://bugs.launchpad.net/bugs/759725 for details and a permanent workaround.

In a container environment, testing the kernel version doesn't make sense anyway, as the host kernel will always be in use. Maybe you could disable the test if you detect a container? There are many ways to do this, e.g.:

1.) Manually

Detect Libvirt-LXC:
# grep -z '^LIBVIRT_LXC_NAME=' /proc/1/environ
LIBVIRT_LXC_NAME=xyz

Detect LXC:
# grep -z '^container=' /proc/1/environ
container=lxc

Detect Linux-Vserver (VxID > 0):
# grep -E '^VxID:\s+[1-9]' /proc/self/status
VxID: 40010

(See /etc/init/container-detect.conf on 14.04 for more examples)

2.) With upstart (14.04 LTS)

# cat /run/container_type
lxc-libvirt

3.) With systemd (16.04 Development)

# systemd-detect-virt -c
lxc-libvirt

---

# ls -la /boot/
total 8
drwxr-xr-x 2 root root 4096 Apr 11 2014 .
drwxr-xr-x 22 root root 4096 Jan 7 23:15 ..

# lsb_release -rd
Description: Ubuntu Xenial Xerus (development branch)
Release: 16.04

# apt-cache policy hobbit-plugins
hobbit-plugins:
  Installiert: 20151005
  Installationskandidat: 20151005
  Versionstabelle:
 *** 20151005 500
        500 http://de.archive.ubuntu.com/ubuntu xenial/universe amd64 Packages
        100 /var/lib/dpkg/status

[Axel Beckert (xtaran)]

Thanks for the bug report.

Fix committed in git in Debian: https://anonscm.debian.org/cgit/collab-maint/hobbit-plugins.git/commit/?id=ce1ae825c922f32033d45f9cc7dcea4140adc016

[Launchpad Janitor (janitor)]

This bug was fixed in the package hobbit-plugins - 20160122

---------------
hobbit-plugins (20160122) unstable; urgency=low

  [ Christoph Berg ]
  * Restructure source to "make install" easier.
  * misc, xynagios: Rewrite to use IPC::Run.
  * Install xynagios to /usr/bin (but provide symlink from old location).
  * xynagios: Add --test option and options to configure RRD trends data.
  * Add t/xynagios.t.

  [ Axel Beckert ]
  * temp: Fix uninitialized values if /sys/devices/platform/*/temp*_input
    exists, has read permissions, but is still not readable.
  * Fix the remaining occurrences of "bb-hosts" in the documentation.
  * libs: Don't warn if no kernel is found, e.g. in containers. (LP:
    #1534220)
  * Remove obsolete "GPL-2" license paragraph in debian/copyright. Thanks
    Lintian!
  * Bump debhelper compatibility to 9 as recommended.
  * mq:
    + Recognize when GMail/Google is blocking the monitored server.
    + Ignore possible RBL issues from ocmail<somenumber>.in.
    + Don't count greylisting, local problems on the remote server, too
      much load on the remote server or shutting down servers as RBL
      issues.
  * Get test suite working again by adding a symlink lib →
    src/usr/share/perl5. Also replace "perl -Iperl" in individual tests by
    using "prove -l". That way (using "lib" instead of "perl" as source
    code path name) the test suite is also closer to what's standard in
    the Perl community.

  [ Mathias Merscher ]
  * Add /etc/xymon/plugins.yaml for plugin configuration.
  * Make entropy and ntpq tests configurable, add ntpq graph.
  * Add netstats test.

 -- Axel Beckert <email address hidden> Fri, 22 Jan 2016 15:13:58 +0100