Linux SSH · Centreon documentation

Overview

Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds.

Plugin-Pack Assets

Monitored Objects

This Plugin-Pack provides assets to monitor all types of Linux based systems with a SSH server enabled:

Centos
Redhat
Debian
Ubuntu
Fedora
...

Collected Metrics

Cpu

Cpu Detailled

Memory

Filesdate

Filessize

Diskio

Openfiles

Swap

Load

Uptime

Paging

Connections

Inodes

Process

Ntp

Quota

Storage

Traffic

Metric name	Description
cpu.utilization.percentage	CPU utilization. Unit : %
core.cpu.utilization.percentage	CPU utilization by core. Unit : %

Per CPU :

Metric name	Description
cpu_user	Average user for CPU. Unit : %
cpu_nice	Average nice for CPU. Unit : %
cpu_system	Average system for CPU. Unit : %
cpu_idle	Average idle for CPU. Unit : %
cpu_wait	Average wait for CPU. Unit : %
cpu_interrupt	Average interrupt for CPU. Unit : %
cpu_softirq	Average softirq for CPU. Unit : %
cpu_steal	Average steal for CPU. Unit : %
cpu_guest	Average guest for CPU. Unit : %
cpu_guestnice	Average guest nice for CPU. Unit : %

Total :

Metric name	Description
total_cpu_guest_avg	Total average guest CPUs. Unit : %
total_cpu_guestnice_avg	Total average guest nice CPUs. Unit : %
total_cpu_idle_avg	Total average idle CPUs. Unit : %
total_cpu_interrupt_avg	Total average interrupt CPUs. Unit : %
total_cpu_nice_avg	Total average nice CPUs. Unit : %
total_cpu_softirq_avg	Total average softirq CPUs. Unit : %
total_cpu_steal_avg	Total average steal CPUs. Unit : %
total_cpu_system_avg	Total average system CPUs. Unit : %
total_cpu_user_avg	Total average user CPUs. Unit : %
total_cpu_wait_avg	Total average wait CPUs. Unit : %

Metric name	Description
used	Memory used. Unit : B
slab	Slab allocation memory used. Unit : B
buffer	Memory buffured. Unit : B
cached	Memory cached. Unit : B

Metric name	Description
name	Time (modified, creation,...) of files/directories. Unit: s

Metric name	Description
name	Size of one file/directorie. Unit : B
total	Total Size of files/directories. Unit : B

Metric name	Description
device.io.read.usage.bytespersecond	Read IO usage in Bytes per second. Unit : B/s
device.io.write.usage.bytespersecond	Write IO usage in Bytes per second. Unit : B/s
device.io.read.time.milliseconds	Read time in milliseconds. Unit : ms
device.io.write.time.milliseconds	Write time in milliseconds. Unit : ms
device.io.utils.percentage	IO utilization for different usage type of CPU. Unit : %

Metric name	Description
system.files.open.count	Number of files opened on the system

Metric name	Description
swap.usage.bytes	Swap usage. Unit: B
swap.free.bytes	Swap free. Unit: B
swap.usage.percentage	Swap usage in percentage. Unit: %

Metric name	Description
load1	Load average on 1 minute.
load5	Load average on 5 minutes.
load15	Load average on 15 minutes.

Metric name	Description
uptime	Duration of system has been working and available. Unit : s

Metric name	Description
system.pgpgin.usage.bytespersecond	Usage of the number of pgpgin in bytes per second. Unit : B/s
system.pgpgout.usage.bytespersecond	Usage of the number of pgpgout in bytes per second. Unit : B/s
system.pswpin.usage.bytespersecond	Usage of the number of pswpin in bytes per second. Unit : B/s
system.pswpout.usage.bytespersecond	Usage of the number of pages in bytes per second. Unit : B/s
system.pgfault.usage.bytespersecond	Usage pgfault in bytes per second. Unit : B/s
system.pgmajfault.usage.bytespersecond	Usage pgmajfault in bytes per second. Unit : B/s

Metric name	Description
app	Number of application connection
service	Number of service connection
con_closed	Number of connection closed
con_closeWait	Number of connection on wait close
con_closing	Number of connection closing
con_established	Number of connection etablished
con_finWait1	Number of connection finWait1
con_finWait2	Number of connection finWait1
con_lastAck	Number of connection on last Ack
con_listen	Number of connection on listen
con_synReceived	Number of connection synchronized Received
con_synSent	Number of connection synchronized syn Sent
con_timeWait	Number of connection on time wait
total	Total of connection

Metric name	Description
used	Inodes space usage on partitions. Unit : %

Metric name	Description
nbproc	Number of current processes.

Metric name	Description
offset	Offset of ntpd service. Unit : ms

Metric name	Description
data_used	Quota usage on partitions. Unit : B

Metric name	Description
used	Storage usages. Unit : B

Metric name	Description
status	Status of the interface
interface.traffic.in.bitspersecond	Incoming traffic going through the interface. Units: b/s
interface.traffic.out.bitspersecond	Outgoing traffic going through the interface. Units: b/s

Prerequisites

SSH configuration

A user is required to query the OS Linux by SSH. There is no need for root or sudo privileges. There are two possible ways to perform SSH check, either by exchanging the SSH key from centreon-engine to the target server, or by setting your unique user and password directly in the host macros.

SSH keys exchange

User/Password Authentication

Add and generate a password for your user on the Target sever:

adduser ro_ssh_centreon
passwd ro_ssh_centreon

Switch to centreon-engine's bash environment on your Central server and Poller :

su - centreon-engine

Then, copy this key on to the Target server with the following commands:

ssh-keygen -t ed25519 -a 100
ssh-copy-id -i .ssh/id_ed25519.pub ro_ssh_centreon@<IP_TARGET_SERVER>

After setting the Name, Alias, IP, and Host Template parameters, you need to set up in the macros described in the Configuration part below.

Installation

Online IMP Licence & IT-100 Editions

Offline IMP License

Install the Centreon Plugin on every poller monitoring Linux SSH resources:

yum install centreon-plugin-Operatingsystems-Linux-Ssh.noarch

On the Centreon Web interface in "Configuration > Plugin packs > Manager", install the Linux SSH Plugin-Pack

Install the Centreon Plugin on every poller monitoring Linux SSH resources:

yum install centreon-plugin-Operatingsystems-Linux-Ssh.noarch

On the Centreon Central server, install the Centreon Plugin-Pack from the RPM:

yum install centreon-pack-operatingsystems-linux-ssh.noarch

On the Centreon Web interface in "Configuration > Plugin packs > Manager", install the Linux SSH Plugin-Pack

Configuration

Add a new Host and apply the Os-Linux-SSH-custom Host Template. Once the template set, you have to set values according to the chosen SSH backend. 3 SSH backends are available to connect to the Linux server: sshcli, plink and libssh which are detailed below.

sshcli backend

Mandatory	Name	Description
X	SSHBACKEND	Name of the backend: `sshcli`
X	SSHUSERNAME	By default, it uses the user running process `centengine` on your poller
	SSHPASSWORD	Cannot be used with backend. Only ssh key authentication
	SSHPORT	By default: 22
	SSHEXTRAOPTIONS	Customize it with your own if needed. E.g.: `--ssh-priv-key=/user/.ssh/id_rsa`

Warning With that backend, you have to validate the target server fingerprint manually (with the SSHUSERNAME used).

plink backend

Mandatory	Name	Description
X	SSHBACKEND	Name of the backend: `plink`
X	SSHUSERNAME	By default, it uses the user running process `centengine` on your poller
	SSHPASSWORD	Can be used. If not set, SSH key authentication is used
	SSHPORT	By default: 22
	SSHEXTRAOPTIONS	Customize it with your own if needed. E.g.: `--ssh-priv-key=/user/.ssh/id_rsa`

Warning With that backend, you have to validate the target server fingerprint manually (with the SSHUSERNAME used).

libssh backend (by default)

Mandatory	Name	Description
X	SSHBACKEND	Name of the backend: `libssh`
X	SSHUSERNAME	By default, it uses the user running process `centengine` on your poller
	SSHPASSWORD	Can be used. If not set, SSH key authentication is used
	SSHPORT	By default: 22
	SSHEXTRAOPTIONS	Customize it with your own if needed. E.g.: `--ssh-priv-key=/user/.ssh/id_rsa`

With that backend, you don't have to validate the target server fingerprint manually.

FAQ

How to check in the CLI that the configuration is OK and what are the main options for ?

Once the Plugin installed, log into your poller using the centreon-engine user account and test by running the following command :

 /usr/lib/centreon/plugins//centreon_linux_ssh.pl \
    --plugin=os::linux::local::plugin \
    --mode='cpu' \
    --hostname='10.30.2.114' \
    --ssh-backend='libssh' \
    --ssh-username='myuser' \
    --ssh-password='mypassword' \
    --ssh-port='22' \
    --warning-core='60' \
    --critical-core='70' \
    --warning-average='60' \
    --critical-average='75' \
    --verbose \
    --use-new-perfdata
        
OK: CPU(s) average usage is 11.91 % - CPU '0' usage : 11.91 % |
'cpu.utilization.percentage'=11.91%;;;0;100 '0#core.cpu.utilization.percentage'=11.91%;;;0;100 
CPU '0' usage : 11.91 %

The check command gives the average CPU of a device using SSH (--mode=CPU). It uses a SSH username centreon (--ssh-username=centreon), a SSH password centreon-password (--ssh-password='centreon-password'), uses a SSH backend libssh (--ssh-backend='libssh') and it connects to the host 10.30.2.114 (--hostname=10.30.2.114) on the SSH default port 22 (---ssh-port=22).

This command will trigger a WARNING alarm if the CPU Average increases to more than 60% (--warning-average='60') and a CRITICAL alarm if more than 75% (--critical-average='75').

Thresholds can be set on all of the device metrics using the syntax --warning-*metric* --critical-*metric*.

All the options that can be used with this plugin can be found over the --help command:

/usr/lib/centreon/plugins//centreon_linux_ssh.pl --plugin=os::linux::local::plugin 
--mode=cpu --help

I have that error message: `UNKNOWN: Command error: Host key verification failed.`. What does it mean ?

It means you haven't manually validated the target server fingerprint with ssh or plink on the Centreon poller.