Microsoft System Center Operations Manager (SCOM) - VictorOps Alerting

VictorOps_Alert.ps1

<#
.SYNOPSIS
    VictorOps Alerting from Microsoft System Center Operations Manager (SCOM) through PowerShell
        Call this script from SCOM's command notification channel - be sure to update the API key (parameter #2). See Example for usage.
.DESCRIPTION
   Post alerts to VictorOps from Microsoft System Center Operations Manager (SCOM) through PowerShell
.EXAMPLE
    FULL PATH OF THE COMMAND FILE:       C:\windows\system32\WindowsPowerShell\v1.0\powershell.exe
    COMMAND LINE PARAMETERS:             "C:\scripts\VO_Send-Alert_Test.ps1" '"$Data[Default='Not Present']/Context/DataItem/AlertId$"' '"$RoutingKey"' '"api-key"'
                                            # !Change $RoutingKey to the routing key you would like to pass in or remove it alltogether to default to 'everyone'
                                            # !Change api-key to the organization api key or default it in parameter #2
    STARTUP FOLDER FOR THE COMMAND LINE: C:\windows\system32\WindowsPowerShell\v1.0\
.EXAMPLE
  # Easier to look at:
    "C:\scripts\VO_Send-Alerts.ps1" ^
    '"$Data[Default='Not Present']/Context/DataItem/AlertId$"' ^
    '"$RoutingKey"'' ^
    '"api-key"'
        # Change $RoutingKey to the routing key you would like to pass in, or remove it alltogether to default to 'everyone'
.NOTES
    Credit to [PagerDuty's integration](http://www.pagerduty.com/docs/guides/scom-integration-guide/) 
            & [nategrieb](https://github.com/nategrieb/VictorOps-SalesForce/blob/master/VictorOpsTimeLine%20Apex%20Class)
            & [Marion Garcia](http://www.systemcentercentral.com/forums-archive/topic/scom-2012-r2-command-notification-channel-using-powershell/)
#>

Param (
    [Parameter(Mandatory=$true ,Position=0,HelpMessage="Unique AlertID must be provided.")][GUID]$AlertID,
    [Parameter(Mandatory=$false,Position=1,HelpMessage="Team routing key, optional.")]     [String]$RoutingKey     = "everyone",
    [Parameter(Mandatory=$false,Position=2,HelpMessage="Organization API key (see REST API Integrations settings in VictorOps), optional.")][String]$API = "",
    [Parameter(Mandatory=$false,Position=3,HelpMessage="Monitoring tool, optional.")]      [String]$MonitoringTool = "Microsoft System Center Operations Manager"
)

# Required: OperationsManager Module
Import-Module OperationsManager

## Find the alert
$Alert = Get-SCOMAlert | where {$_.id -eq $AlertID.ToString()}

# Determine the status of the alert
switch ($Alert.ResolutionState){
        0       {$Status="CRITICAL"} 
        255     {$Status="RECOVERY"}
        default {$Status="CRITICAL"}
    }

# workaround for unix/linux hosts - hostnames do not come through clearly in SCOM
if($Alert.NetbiosComputerName -ne $null){ $hstname = $alert.NetbiosComputerName }
elseif($Alert.MonitoringObjectPath -ne $null){ $hstname = $alert.MonitoringObjectFullName }
else { $hstname = $alert.MonitoringObjectName }

## Setup our Subject & StateMessage to be passed
[String]$Subject = $Status + ": " + $Alert.Name + " [" + $hstname + "]"
[String]$StateMessage = "Description: "          + $Alert.Description                 + "`n" `
                        + "Hostname: "           + $hstname                           + "`n" `
                        + "Timestamp: "          + $Alert.TimeRaised.ToLocalTime()    + " PST `n" `
                        + "Team: "               + $RoutingKey.ToUpper()              + "`n" `
                        + "Last modified by: "   + $Alert.LastModifiedBy              + "`n" `
                        + "Last modified time: " + $Alert.LastModified                + "`n" `

## Convert to json
$props = @{
    message_type        = $Status;                         #[String] One of the following values: INFO, WARNING, ACKNOWLEDGMENT, CRITICAL, RECOVERY
    timestamp           = $Alert.TimeRaised.ToLocalTime(); #[Number] Timestamp of the alert in seconds since epoch. Defaults to the time the alert is received at VictorOps.
    entity_id           = $Alert.id.ToString();            #[String] The name of alerting entity. If not provided, a random name will be assigned.
    entity_display_name = $Subject;                        #[String] Used within VictorOps to display a human-readable name for the entity.
    hostname            = $hstname;                        #[String] System hostname (set above via logic)
    monitoring_tool     = $MonitoringTool;                 #[String] The name of the monitoring system software (eg. nagios, icinga, sensu, etc.)
    state_message       = $StateMessage;                   #[String] Any additional status information from the alert item.
    Subject             = $Subject;
}
$json = ConvertTo-Json -InputObject $props

## Log alert

# Event-log
$CheckEventLog = (Get-EventLog -List | ? Log -EQ "OM Alerts")
if($CheckEventLog -eq $null){ 
    try{New-EventLog -LogName "OM Alerts" -Source "VictorOps Alerts"}
    catch{Write-Error "Please rerun the script from a Windows PowerShell console with admin rights ('Run As Administrator'). Cannot continue.";Break}
}
$event_message = $StateMessage + "`n Command: " + "Invoke-RestMethod -Method Post -ContentType `"application/json`" -Body `n$json`n -Uri `"https://alert.victorops.com/integrations/generic/20131114/alert/$API/$RoutingKey`""

Write-EventLog -LogName "OM Alerts" -Source "VictorOps Alerts" -Message $event_message -EventId 2 -EntryType Information

<# Text file
$Logstring =  $StateMessage.replace("`n"," ")
$Logfile = "C:\scripts\VO_Send-Alerts.log" 
$DateTime = Get-Date -Uformat "%y-%m-%d %H:%M:%S" 
$Logstring = $DateTime + " " + $Logstring 
Add-content $Logfile -value $Logstring
$json | Out-File -FilePath "C:\scripts\VO_Send-Alerts.$RoutingKey.json"
#>

# Post the alert
Invoke-RestMethod -Method Post `
                  -ContentType "application/json" `
                  -Body $json `
                  -Uri "https://alert.victorops.com/integrations/generic/20131114/alert/$API/$RoutingKey"

When executing the Script it asks me to add the AlertID, any ideas?

:\Program Files\Microsoft System Center 2016\Operations Manager\PowerShell> C:\Scripts\VictorOps_Alert.ps1
cmdlet VictorOps_Alert.ps1 at command pipeline position 1
Supply values for the following parameters:
AlertID:

Achamblat - this script was developed in 2015 for a much older version of PowerShell, SCOM & Victorops (now Splunk Oncall). I cannot say whether or not it is compatible with the latest version of either. I cannot recommend using this in a production environment without a rewrite.
That being said, based on your question - you need to look up the SCOM Alert ID and pass that into the script as the AlertID parameter.