Powershell script to create snapshots of the PVCs used by an AKS

Perform-Pvc-Backup.ps1

#Parameter section
Param
(
    [Parameter(Mandatory = $false, HelpMessage = 'Subscription id to use')][String] $subscriptionId = "",
    [Parameter(Mandatory = $true, HelpMessage = 'AKS Resource group')][String] $rg,
    [Parameter(Mandatory = $false, HelpMessage = 'Resource group to store the snapshots (default: AKS nodes RG)')][String] $destinationRg="",
    [Parameter(Mandatory = $false, HelpMessage = 'AKS name (in the RG)')][String] $aksName,
    [Parameter(Mandatory = $false, HelpMessage = 'PVCs to backup')][String[]] $pvcsToBackup= [string []]"",
    [Parameter(Mandatory = $false, HelpMessage = 'Tag used to identify if disk is AKS managed')][String] $tagCreatedBy="created-by",
    [Parameter(Mandatory = $false, HelpMessage = 'Tag used to identify if disk is AKS managed')][String] $tagCreatedByValue="kubernetes-azure-dd",
    [Parameter(Mandatory = $false, HelpMessage = 'Tag used to get tge PVC name of the disk')][String] $tagPvcName="kubernetes.io-created-for-pvc-name",
    [Parameter(Mandatory = $false, HelpMessage = 'Tag used to get tge PVC namespace of the disk')][String] $tagPvcNamespace="kubernetes.io-created-for-pvc-namespace",
    [Parameter(Mandatory = $false, HelpMessage = 'If true does nothing (only displays info)')][Boolean] $dryRun=$false
)

function Build-Snapshot ($disk, $aks, [string]$destRg, [string]$pvcName, [string]$pvcNamespace) {
    $date = Get-Date
    $snapshotName = $pvcNamespace + "-" + $pvcName +  "-" + $date.Year + "-" + $date.Month + "-" + $date.Day + "-" + $date.Hour + "-" + $date.Minute
    Write-Host "Creating snapshot $snapshotName in RG $destRg"
    if (-not $dryRun) {
        $snapshot = $(az snapshot create -g $destinationRg -n $snapshotName --source $disk.id -ojson | ConvertFrom-Json)
        if( -not $? ) {
            Write-Host "Error creating snapshot :(" -ForegroundColor Red
            exit 1
        }
        az tag create --resource-id $snapshot.id --tags "pvc=$pvcName" "namespace=$pvcNamespace" "aks=$($aks.name)" "aks_rg=$($aks.resourceGroup)"
    }
    else {
        Write-Host "NOTE: Snapshot not created due to dryRun enabled"
    }
}

if ([String]::IsNullOrEmpty($subscriptionId)) {
    $subscriptionId = $(az account show --query id -otsv)
}
else {
    az account set -s $subscriptionId
    if( -not $? ) {
        Write-Host "Error setting subscrption $subscriptionId" -ForegroundColor Red
        exit 1
    }
}

if ([String]::IsNullOrEmpty($aksName)) {
    $numAks = $(az aks list -g $rg -ojson | ConvertFrom-Json).Length
    if ($numAks -ne 1) {
        Write-Host "Detected $numAks AKS in the RG $rg." -ForegroundColor Red
        if ($numAks -gt 1) {
            Write-Host "Please use parameter aksName to set the AKS to use. "
        }
        exit 1
    }
    $aks = $(az aks list -g $rg -ojson | ConvertFrom-Json)[0]
}
else {
    $aks = $(az aks show -n $aksName -g $rg -ojson | ConvertFrom-Json)
    if( -not $? ) {
        Write-Host "Error getting AKS $aksName in RG $rg" -ForegroundColor Red
        exit 1
    }
}

Write-Host "Using AKS $($aks.name) in subscription $subscriptionId"  -ForegroundColor Yellow

$nodeResourceGroup = $aks.nodeResourceGroup
if ([String]::IsNullOrEmpty($destinationRg)) {
    $destinationRg = $nodeResourceGroup
}

$disks = $(az disk list -g $nodeResourceGroup -ojson | ConvertFrom-Json)
Foreach ($disk in $disks) {
    if ($disk.managedBy) {
        Write-Host "Found disk $($disk.id)" -ForegroundColor Yellow
        $createdby = $disk.tags."$tagCreatedBy"
        $pvcName = $disk.tags."$tagPvcName"
        $pvcNamespace = $disk.tags."$tagPvcNamespace"
        if ($createdby -eq $tagCreatedByValue) {
            Write-Host "Disk is for $pvcNamespace/$pvcName" -ForegroundColor Green
            if ($pvcsToBackup.Contains($pvcName)) {
                Write-Host "Found! Creating snapshot"
                Build-Snapshot -disk $disk -aks $aks -destRg $destinationRg -pvcName $pvcName -pvcNamespace $pvcNamespace
            }
        }
    }  
}