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Linux SSH

Pack assets​

This Monitoring Connector provides assets to monitor all types of Linux based systems with a SSH server that is enabled.

Templates​

The Monitoring Connector Linux SSH brings a host template:

  • OS-Linux-SSH-custom

The connector brings the following service templates (sorted by the host template they are attached to):

Service AliasService TemplateService Description
ConnectionsOS-Linux-Connections-SSH-customCheck tcp
CpuOS-Linux-Cpu-SSH-customCheck system CPUs
InodesOS-Linux-Inodes-SSH-customCheck inodes
LoadOS-Linux-Load-SSH-customCheck load average
MemoryOS-Linux-Memory-SSH-customCheck memory
Open-FilesOS-Linux-Open-Files-SSH-customCheck open files
PagingOS-Linux-Paging-SSH-customCheck paging informations
ProcessOS-Linux-Process-SSH-customCheck processes
SwapOS-Linux-Swap-SSH-customCheck swap usage
UptimeOS-Linux-Uptime-SSH-customCheck uptime

The services listed above are created automatically when the OS-Linux-SSH-custom host template is used.

Discovery rules​

Service discovery​

Rule nameDescription
OS-Linux-SSH-Systemd-Sc-Status-NameDiscover Linux services and monitor status

More information about discovering services automatically is available on the dedicated page and in the following chapter.

Collected metrics & status​

Here is the list of services for this connector, detailing all metrics linked to each service.

Metric nameUnit
command.exit.code.count

Prerequisites​

SSH configuration​

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

Installing the monitoring connector​

Pack​

  1. If the platform uses an online license, you can skip the package installation instruction below as it is not required to have the connector displayed within the Configuration > Monitoring Connectors Manager menu. If the platform uses an offline license, install the package on the central server with the command corresponding to the operating system's package manager:
dnf install centreon-pack-operatingsystems-linux-ssh
  1. Whatever the license type (online or offline), install the Linux SSH connector through the Configuration > Monitoring Connectors Manager menu.

Plugin​

Since Centreon 22.04, you can benefit from the 'Automatic plugin installation' feature. When this feature is enabled, you can skip the installation part below.

You still have to manually install the plugin on the poller(s) when:

  • Automatic plugin installation is turned off
  • You want to run a discovery job from a poller that doesn't monitor any resource of this kind yet

More information in the Installing the plugin section.

Use the commands below according to your operating system's package manager:

dnf install centreon-plugin-Operatingsystems-Linux-Ssh

Using the monitoring connector​

Using a host template provided by the connector​

  1. Log into Centreon and add a new host through Configuration > Hosts.
  2. Fill the Name, Alias & IP Address/DNS fields according to your ressource settings.
  3. Apply the OS-Linux-SSH-custom template to the host. A list of macros appears. Macros allow you to define how the connector will connect to the resource, and to customize the connector's behavior.
  4. Fill in the macros you want. Some macros are mandatory.
MacroDescriptionDefault valueMandatory
SSHUSERNAMEDefine the user name to log in to the host
SSHPASSWORDDefine the password associated with the user name. Cannot be used with the sshcli backend. Warning: using a password is not recommended. Use --ssh-priv-key instead
SSHPORTDefine the TCP port on which SSH is listening
SSHBACKENDDefine the backend you want to use. It can be: sshcli (default), plink and libsshlibssh
SSHEXTRAOPTIONSAny extra option you may want to add to every command (E.g. a --verbose flag). All options are listed here
  1. Deploy the configuration. The host appears in the list of hosts, and on the Resources Status page. The command that is sent by the connector is displayed in the details panel of the host: it shows the values of the macros.

Using a service template provided by the connector​

  1. If you have used a host template and checked Create Services linked to the Template too, the services linked to the template have been created automatically, using the corresponding service templates. Otherwise, create manually the services you want and apply a service template to them.
  2. Fill in the macros you want (e.g. to change the thresholds for the alerts). Some macros are mandatory (see the table below).
MacroDescriptionDefault valueMandatory
EXECCOMMANDCommand to test (Default: none). You can use 'sh' to use '&&' or '||'X
EXECCOMMANDOPTIONSCommand options (Default: none)
MANAGERETURNSSet action according command exit code. Example: %(code) == 0,OK,File xxx exist#%(code) == 1,CRITICAL,File xxx not exist#,UNKNOWN,Command problemX
EXTRAOPTIONSAny extra option you may want to add to the command (E.g. a --verbose flag). All options are listed here
  1. Deploy the configuration. The service appears in the list of services, and on page Resources Status. The command that is sent by the connector is displayed in the details panel of the service: it shows the values of the macros.

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

Once the plugin is installed, log into your Centreon poller's CLI using the centreon-engine user account (su - centreon-engine). Test that the connector is able to monitor a resource using a command like this one (replace the sample values by yours):

/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='centreon' \
    --ssh-password='centreon-password' \
    --ssh-port='22' \
    --warning-core='60' \
    --critical-core='70' \
    --warning-average='60' \
    --critical-average='75' \
    --verbose

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

The expected command output is shown below:

OK: CPU(s) average usage is 2.98 % | 'cpu.utilization.percentage'=2.98%;;;0;100 '0#core.cpu.utilization.percentage'=3.18%;;;0;100 '1#core.cpu.utilization.percentage'=2.39%;;;0;100 '2#core.cpu.utilization.percentage'=4.16%;;;0;100 '3#core.cpu.utilization.percentage'=2.19%;;;0;100
CPU '0' usage : 3.18 %
CPU '1' usage : 2.39 %
CPU '2' usage : 4.16 %
CPU '3' usage : 2.19 %

Troubleshooting​

Please find the troubleshooting documentation for Centreon Plugins typical issues.

Available modes​

In most cases, a mode corresponds to a service template. The mode appears in the execution command for the connector. In the Centreon interface, you don't need to specify a mode explicitly: its use is implied when you apply a service template. However, you will need to specify the correct mode for the template if you want to test the execution command for the connector in your terminal.

All available modes can be displayed by adding the --list-mode parameter to the command:

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

The plugin brings the following modes:

ModeLinked service template
check-plugin [code]Not used in this Monitoring Connector
cmd-return [code]OS-Linux-Cmd-Return-SSH-custom
connections [code]OS-Linux-Connections-SSH-custom
cpu [code]OS-Linux-Cpu-SSH-custom
cpu-detailed [code]OS-Linux-Cpu-Detailed-SSH-custom
discovery-snmp [code]Not used in this Monitoring Connector
discovery-snmpv3 [code]Not used in this Monitoring Connector
diskio [code]OS-Linux-Disk-Io-SSH-custom
files-date [code]OS-Linux-Files-Date-SSH-custom
files-size [code]OS-Linux-Files-Size-SSH-custom
inodes [code]OS-Linux-Inodes-SSH-custom
list-interfaces [code]Not used in this Monitoring Connector
list-partitions [code]Not used in this Monitoring Connector
list-storages [code]Not used in this Monitoring Connector
list-systemdservices [code]Used for service discovery
load [code]OS-Linux-Load-SSH-custom
lvm [code]OS-Linux-Lvm-SSH-custom
memory [code]OS-Linux-Memory-SSH-custom
mountpoint [code]OS-Linux-Mountpoint-SSH-custom
ntp [code]OS-Linux-Ntp-SSH-custom
open-files [code]OS-Linux-Open-Files-SSH-custom
packet-errors [code]OS-Linux-Packet-Errors-SSH-custom
paging [code]OS-Linux-Paging-SSH-custom
pending-updates [code]OS-Linux-Pending-Updates-SSH-custom
process [code]OS-Linux-Process-SSH-custom
quota [code]OS-Linux-Quota-SSH-custom
storage [code]OS-Linux-Storages-SSH-custom
swap [code]OS-Linux-Swap-SSH-custom
systemd-journal [code]OS-Linux-Systemd-Journal-SSH-custom
systemd-sc-status [code]OS-Linux-Systemd-Sc-Status-SSH-custom
traffic [code]OS-Linux-Traffic-SSH-custom
uptime [code]OS-Linux-Uptime-SSH-custom

Available options​

Generic options​

All generic options are listed here:

OptionDescription
--modeDefine the mode in which you want the plugin to be executed (see--list-mode).
--dyn-modeSpecify a mode with the module's path (advanced).
--list-modeList all available modes.
--mode-versionCheck minimal version of mode. If not, unknown error.
--versionReturn the version of the plugin.
--custommodeWhen a plugin offers several ways (CLI, library, etc.) to get information the desired one must be defined with this option.
--list-custommodeList all available custom modes.
--multipleMultiple custom mode objects. This may be required by some specific modes (advanced).
--pass-managerDefine the password manager you want to use. Supported managers are: environment, file, keepass, hashicorpvault and teampass.
--verboseDisplay extended status information (long output).
--debugDisplay debug messages.
--filter-perfdataFilter perfdata that match the regexp. Eg: adding --filter-perfdata='avg' will remove all metrics that do not contain 'avg' from performance data.
--filter-perfdata-advFilter perfdata based on a "if" condition using the following variables: label, value, unit, warning, critical, min, max. Variables must be written either %{variable} or %(variable). Eg: adding --filter-perfdata-adv='not (%(value) == 0 and %(max) eq "")' will remove all metrics whose value equals 0 and that don't have a maximum value.
--explode-perfdata-maxCreate a new metric for each metric that comes with a maximum limit. The new metric will be named identically with a '_max' suffix). Eg: it will split 'used_prct'=26.93%;0:80;0:90;0;100 into 'used_prct'=26.93%;0:80;0:90;0;100 'used_prct_max'=100%;;;;
--change-perfdata --extend-perfdataChange or extend perfdata. Syntax: --extend-perfdata=searchlabel,newlabel,target[,[newuom],[min],[m ax]] Common examples: Convert storage free perfdata into used: --change-perfdata=free,used,invert() Convert storage free perfdata into used: --change-perfdata=used,free,invert() Scale traffic values automatically: --change-perfdata=traffic,,scale(auto) Scale traffic values in Mbps: --change-perfdata=traffic_in,,scale(Mbps),mbps Change traffic values in percent: --change-perfdata=traffic_in,,percent()
--extend-perfdata-groupAdd new aggregated metrics (min, max, average or sum) for groups of metrics defined by a regex match on the metrics' names. Syntax: --extend-perfdata-group=regex,namesofnewmetrics,calculation[,[ne wuom],[min],[max]] regex: regular expression namesofnewmetrics: how the new metrics' names are composed (can use $1, $2... for groups defined by () in regex). calculation: how the values of the new metrics should be calculated newuom (optional): unit of measure for the new metrics min (optional): lowest value the metrics can reach max (optional): highest value the metrics can reach Common examples: Sum wrong packets from all interfaces (with interface need --units-errors=absolute): --extend-perfdata-group=',packets_wrong,sum(packets_(discard |error)_(in|out))' Sum traffic by interface: --extend-perfdata-group='traffic_in_(.*),traffic_$1,sum(traf fic_(in|out)_$1)'
--change-short-output --change-long-outputModify the short/long output that is returned by the plugin. Syntax: --change-short-output=pattern~replacement~modifier Most commonly used modifiers are i (case insensitive) and g (replace all occurrences). Eg: adding --change-short-output='OK~Up~gi' will replace all occurrences of 'OK', 'ok', 'Ok' or 'oK' with 'Up'
--change-exitReplace an exit code with one of your choice. Eg: adding --change-exit=unknown=critical will result in a CRITICAL state instead of an UNKNOWN state.
--range-perfdataRewrite the ranges displayed in the perfdata. Accepted values: 0: nothing is changed. 1: if the lower value of the range is equal to 0, it is removed. 2: remove the thresholds from the perfdata.
--filter-uomMask the units when they don't match the given regular expression.
--opt-exitReplace the exit code in case of an execution error (i.e. wrong option provided, SSH connection refused, timeout, etc). Default: unknown.
--output-ignore-perfdataRemove all the metrics from the service. The service will still have a status and an output.
--output-ignore-labelRemove the status label ("OK:", "WARNING:", "UNKNOWN:", CRITICAL:") from the beginning of the output. Eg: 'OK: Ram Total:...' will become 'Ram Total:...'
--output-xmlReturn the output in XML format (to send to an XML API).
--output-jsonReturn the output in JSON format (to send to a JSON API).
--output-openmetricsReturn the output in OpenMetrics format (to send to a tool expecting this format).
--output-fileWrite output in file (can be combined with json, xml and openmetrics options). E.g.: --output-file=/tmp/output.txt will write the output in /tmp/output.txt.
--disco-formatApplies only to modes beginning with 'list-'. Returns the list of available macros to configure a service discovery rule (formatted in XML).
--disco-showApplies only to modes beginning with 'list-'. Returns the list of discovered objects (formatted in XML) for service discovery.
--float-precisionDefine the float precision for thresholds (default: 8).
--source-encodingDefine the character encoding of the response sent by the monitored resource Default: 'UTF-8'.
--hostnameHostname to query.
--timeoutTimeout in seconds for the command (Default: 45). Default value can be override by the mode.
--commandCommand to get information. Used it you have output in a file.
--command-pathCommand path.
--command-optionsCommand options.
--sudo sudo command.
--ssh-backendDefine the backend you want to use. It can be: sshcli (default), plink and libssh.
--ssh-usernameDefine the user name to log in to the host.
--ssh-passwordDefine the password associated with the user name. Cannot be used with the sshcli backend. Warning: using a password is not recommended. Use --ssh-priv-key instead.
--ssh-portDefine the TCP port on which SSH is listening.
--ssh-priv-keyDefine the private key file to use for user authentication.
--sshcli-commandssh command (default: 'ssh').
--sshcli-pathssh command path (default: none)
--sshcli-optionSpecify ssh cli options (example: --sshcli-option='-o=StrictHostKeyChecking=no').
--plink-commandplink command (default: 'plink').
--plink-pathplink command path (default: none)
--plink-optionSpecify plink options (example: --plink-option='-T').
--libssh-strict-connectConnection won't be OK even if there is a problem (server known changed or server found other) with the ssh server.

Modes options​

All available options for each service template are listed below:

OptionDescription
--manage-returnsSet action according command exit code. Example: %(code) == 0,OK,File xxx exist#%(code) == 1,CRITICAL,File xxx not exist#,UNKNOWN,Command problem
--separatorSet the separator used in --manage-returns (default : #)
--exec-commandCommand to test (Default: none). You can use 'sh' to use '&&' or '||'.
--exec-command-pathCommand path (Default: none).
--exec-command-optionsCommand options (Default: none).

All available options for a given mode can be displayed by adding the --help parameter to the command:

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