Check AD has synced to Azure AD within the last two hours, if not, send a slack message. Azure Automation runbook.

Test-LastAzureADSyncTime.ps1

# Azure runbook running under an automation account.
#Requires -Modules MSOnline

Import-Module -name MSOnline
$creds = Get-AutomationPSCredential -Name 'AzureADConnectSyncAccount'
Connect-MsolService -Credential $creds
$SlackHook = Get-AutomationVariable -Name 'AlertsSlackWebHookUri'

# Slack helper function
function New-MDSlackMessage {
    <#
    .SYNOPSIS
        Send a message to Slack
    .DESCRIPTION
        Send a JSON payload to slack consisting of a text message
    .EXAMPLE
        New-MDSlackMessage -URI $SlackHook -Message 'hi'
        
        Send the message 'hi' to slack
    .INPUTS
        Inputs (if any)
    .OUTPUTS
        Output (if any)
    .NOTES
        Requires a Slack app https://api.slack.com/apps and the URI of the slack hook and a valid bearer token passed to it
    #>
    param(
        # URI of Slack Hook
        [Parameter(Mandatory = $true, Position = 0)]
        [string]
        $Uri,
        # Message To Send
        [Parameter(Mandatory = $true, Position = 1)]
        [string]
        $Message
    )
    
    $payload = @{
        "text" = $Message
    }

    Invoke-RestMethod -Method Post -Uri $SlackHook  -Body (ConvertTo-Json -InputObject $payload -Compress) -UseBasicParsing | Out-Null
}


<#
.SYNOPSIS
    Check last sync time is within 2 hours 
.DESCRIPTION
    Uses MSOL command to get the last sync time and check it is within two hours.
    If it isn't, send an alert to the slack alerts room.
#>
$CompanyInformation = Get-MsolCompanyInformation

if ((Get-Date).AddHours(-2) -gt $CompanyInformation.LastDirSyncTime) {
    # Send error message
    $Message = "Azure AD Connect`nNo AD to Azure sync for over 2 hours`nLast sync time was: $($CompanyInformation.LastDirSyncTime)`nPlease check sync service on the sync server."
    Write-Output $Message
    New-MDSlackMessage -Uri $Uri -Message $Message
}