check_lxc

Monitoring plugin to check LXC (Linux Container)

Full documentation: https://www.claudiokuenzler.com/monitoring-plugins/check_lxc.php

Usage

sudo ./check_lxc.sh -n container -t type [-u unit] [-w warning] [-c critical]

sudo needed

check_lxc.sh requires to be run with root privileges because certain commands within the plugin require elevated permissions. Therefore create an entry in /etc/sudoers similar to this (adapt to your own environment):

nagios          ALL = NOPASSWD: /usr/lib/nagios/plugins/check_lxc.sh

If you use NRPE, the corresponding command definition could look like this:

command[check_lxc]=sudo /usr/lib/nagios/plugins/check_lxc.sh -n $ARG1$ -t $ARG2$

Options and check types explained

Options:
    -n name of container (or ALL for some types)
    -t type to check (see list below)
    [-u unit of output values (k|m|g)]
    [-w warning threshold] (makes only sense if limit is set in lxc config)
    [-c critical threshold] (makes only sense if limit is set in lxc config)
    [-s sleep in seconds between cpu checks]
    
Types:
    mem -> Check the memory usage of the given container (thresholds in percent)
    swap -> Check the swap usage (thresholds in MB)
    cpu -> Check cpu usage (percentage) of a container (thresholds in percent)
    auto -> Check autostart of container (-n ALL possible)

Examples (container name: lxctest01)

./check_lxc.sh -n lxctest01 -t mem 
LXC lxctest01 OK - Used Memory: 96 MB|mem_used=100941824B;0;0;0;

./check_lxc.sh -n lxctest01 -t mem -w 2 -c 54 
LXC lxctest01 WARNING - Used Memory: 2% (97 MB)|mem_used=101982208B;0;0;0;4294967296

./check_lxc.sh -n lxctest01 -t mem -w 85 -c 95 -u k
LXC lxctest01 OK - Used Memory: 2% (98600 KB)|mem_used=100966400B;0;0;0;4294967296

./check_lxc.sh -n ALL -t auto 
LXC AUTOSTART CRITICAL: lxctest01

./check_lxc.sh -n lxctest01 -t swap -w 50 -c 70
LXC lxctest01 CRITICAL - Used Swap: 81 MB|swap=85680128B;52428800;73400320;0;0

./check_lxc.sh -n lxctest01 -t cpu -w 80 -c 90
LXC lxctest01 OK - CPU Usage: 27%|cpu=27%;80;90;0;0

Enable cgroup memory for memory check

To be able to run the memory check (-t mem), the cgroup subsys "memory" must be enabled. You can verify this manually by running:

cat /proc/cgroups | grep memory

If the first value is not enabled (0), then add the following options as your kernel boot parameter: "cgroup_enable=memory" and "swapaccount=1". In Debian this can be done by modifying /etc/default/grub2 followed by a update of the grub2 and reboot:

# cat /etc/default/grub | grep CMDLINE_LINUX_DEFAULT
GRUB_CMDLINE_LINUX_DEFAULT="quiet cgroup_enable=memory swapaccount=1"

update-grub2
reboot

Then verify if you can get the memory statistics of a container:

lxc-cgroup -n lxctest01 memory.stat