• Article

UNIX/Linux Shell Command Monitors

 

Updated: May 13, 2016

Applies To: System Center 2012 R2 Operations Manager, System Center 2012 - Operations Manager, System Center 2012 SP1 - Operations Manager

UNIX/Linux shell command monitors run on a schedule and execute a program or script, a command, or a one-line command sequence (using pipeline operators). The output from the command is used to determine the health state of the target object. Shell command monitors are useful for custom monitoring of UNIX and Linux applications with information that is not accessible through other means.

Options

When you run an UNIX/Linux shell command monitor wizard, you will need to provide values for options in the following tables. Each table represents a single page in the wizard.

Rule Type

The Rule Type page includes basic settings for the rule including its type and the management pack file to store it in.

Option

Description

Select the type of monitor to create

To create a shell command monitor that evaluates for two states (healthy and error), select UNIX/Linux Shell Command Two State Monitor. To create a shell command monitor that evaluates for three states (healthy, warning and error), select UNIX/Linux Shell Command Three State Monitor.

Management Pack

Management pack file to store the rule or monitor.For more information on management packs, see Selecting a Management Pack File.

General

The General page includes general settings for the rule including its name, category, target, and the management pack file to store it in.

Option

Description

Name

The name used for the monitor. This appears in the Monitors view in the Authoring pane. When you view the Health Explorer for the monitoring target, you can see the health state of this monitor.

Description

Optional description of the rule.

Monitor Target

The class to use for the target of the rule. The rule will be run on any agent that has at least one instance of this class. For more information on targets, see Understanding Classes and Objects.

Parent Monitor

The aggregate monitor that this monitor will be placed under in the Health Explorer.

Monitor is enabled

If checked, the monitor is enabled and the shell command will run according to the schedule. If unchecked, the monitor is not enabled and the script will not run. The monitor can be enabled for a group of target objects by creating an override to enable the monitor.

Schedule

The Schedule page defines the schedule to run the script. The script will run indefinitely according to this schedule until the monitor is disabled or deleted or the management pack is uninstalled.

Option

Description

Run every

Frequency that the script should be run. This should typically not be less than 5 minutes.

Synchronize at

If enabled, the schedule will be synchronized to occur at the specified time.

UNIX/Linux Shell Command

The following options are available on the Shell Command Details page of the wizard.

Option

Description

Command

The shell command to execute. This can be the full path to a program or script, a command, or a one-line sequence of multiple commands (using pipeline operators).

Run As Profile

Either the “UNIX/Linux Action Account” or “UNIX/Linux Privileged Account” profile. Select the profile that associates the required account credentials with the task target. The associated account will be used to execute the command.

Timeout (seconds)

The number of seconds that the command can run before the agent stops it. This prevents problem commands from running continuously and putting excess overhead on the agent computer.

Expressions

Each required expression for the monitor will have its own page in the wizard. A two-state monitor will have the following expressions:

  1. Error Expression

  2. Healthy Expression

A three-state monitor will have the following expressions:

  1. Error Expression

  2. Warning Expression

  3. Healthy Expression

Note

Detailed information on expressions is available in Expressions.

Each expression will typically compare the value of one or more of the properties from the command’s output to some value. Each expression must be different, and only one of the expressions should evaluate to True under any particular condition. In the next page of the wizard, you will associate each of the health states of the monitor with one of these expressions. When an expression evaluates to the True, the monitor will be set to that health state.

Option

Description

Parameter Name

The Parameter Name syntax for command execution output is:StdOut: //*[local-name()="StdOut"]StdErr: //*[local-name()="StdErr"]Return Code: //*[local-name()="ReturnCode"]

Operator

The type of comparison to perform.

Value

The explicit value that should match the value in the property bag.

Configure Health

On this page, you map each of the expressions to a health state for the monitor. When a condition is true, the monitor is set to the health state that you define. For a three-state monitor, you can typically accept the default settings. For a two-state monitor, you typically only have to determine if the Unhealthy Expression should result in a Critical or Warning state.

Option

Description

Monitor Condition

Represents each of the expressions.

Health State

The health state to set the monitor to when that expression is true.

Configure Alerts

Option

Description

Generate alerts for this monitor

If checked, an alert will be created when the monitor changes from a healthy state to a warning or critical state, and all of the other options will be enabled. If unchecked, the monitor will not generate alerts when the health state is changed, and all of the other options will be disabled.

Generate an alert when

For a two-state monitor, this setting should be set to The monitor is in a critical health state.

Automatically resolve alert when the monitor returns to a healthy state

If checked, the alert will automatically be resolved when the monitor returns to a healthy state. If unchecked, the alert must be resolved manually.

Alert name

The name of the alert that is displayed in the console.

Alert Description

The description of the alert.

Priority

The priority of the alert: Low, Medium, or High.

Severity

The severity of the alert: Information, Warning, Critical, or matched to the health state of the monitor.

Creating an UNIX/Linux Shell Command Monitor

The following procedure shows how to create a monitor based on a monitoring shell command with the following details:

  • Runs on any UNIX/Linux computer every 15 minutes

  • Sets the monitor to a Critical state when the file “/tmp/error” exists.

  • Sets the monitor to a Healthy state when the file “/tmp/error" does not exist.

To create a two state UNIX/Linux shell command monitor

  1. If you don’t have a management pack for the application that you are monitoring, create one using the process in Selecting a Management Pack File.

  2. In the Operations console, select the Authoring workspace, and then select Monitors.

  3. Launch the Create a Monitor task, and select Unit Monitor.

  4. On the Monitor Type page, do the following:

    1. Expand Scripting and then expand Generic.

    2. Select UNIX/Linux Shell Command Two State Monitor.

    3. In the Management Pack dropdown, select the management pack from step 1.

    4. Click Next.

  5. On the General page, do the following:

    1. In the Name box, type Error File Test Monitor.

    2. Click Select next to the Monitor Target box, select UNIX/Linux Computer, and click OK.

    3. Select the Parent Monitor of Availability.

    4. Leave the Monitor is enabled box selected.

    5. Click Next.

  6. On the Schedule page, do the following:

    1. In the Run every box, type 15 minutes.

    2. Click Next.

  7. On the Shell Command Details page, do the following:

    1. In the Command box, type ls /tmp/error | wc –l. This command sequence will return a 1 if the file “/tmp/error” exists, and a 0 if it does not.

    2. In the Run As Profile box, select the UNIX/Linux Action Account profile.

    3. In the Timeout (Seconds) box, input 120.

    4. Click Next.

  8. On the Error Expression page, enter the following And expression:

    1. //*[local-name()=”StdOut”] equals 1

    2. //*[local-name()=”ReturnCode”] equals 0

  9. On the HealthyExpression page, enter the following And expression:

    1. //*[local-name()=”StdOut”] does not equal 1

    2. //*[local-name()=”ReturnCode”] equals 0

  10. On the Configure Health page, do the following:

    1. Leave the Health State for the StatusError condition set to Critical.

    2. Click Next.

  11. On the Configure Alerts page, do the following:

    1. Select Generate alerts for this monitor.

    2. In the Generate an alert when box, select The monitor is in a critical health state.

    3. Leave the box selected to automatically resolve the alert.

    4. In the Alert name box, type Application test failed.

    5. Clear the existing text in the Alert description box and type Computer:

    6. Click the ellipse button.

    7. Click Target and then select Network Name.

    8. Click OK.

    9. In the Alert description box, add a new line and type StdOut: $Data/Context///*[local-name()=”StdOut”]$

  12. Click Create.

Note

UNIX and Linux shell commands are saved to the /tmp directory, executed, and then removed from the /tmp directory. The /tmp directory requires exec privileges for using UNIX and Linux shell commands.