Powershell - Create a new Search Service Application in SharePoint 2013

Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue

# Settings
$IndexLocation = Read-Host "Enter Index location eg: C:\Data\Search15Index” #Location must be empty, will be deleted during the process!
$SearchAppPoolName = Read-Host "Enter search Application pool name eg:Search App Pool"
$SearchAppPoolAccountName = Read-Host "Enter search Application pool Account name eg:corp\username"
$SearchServerName = (Get-ChildItem env:computername).value
$SearchServiceName = Read-Host "Enter search Service name eg: Search15"
$SearchServiceProxyName = Read-Host "Enter search Service proxy name eg: Search15 Proxy"
$DatabaseName = Read-Host "Enter Database name eg: Search15_ADminDB"
Write-Host -ForegroundColor Yellow "Checking if Search Application Pool exists"
$SPAppPool = Get-SPServiceApplicationPool -Identity $SearchAppPoolName -ErrorAction SilentlyContinue

if (!$SPAppPool)
{
    Write-Host -ForegroundColor Green "Creating Search Application Pool"
    $spAppPool = New-SPServiceApplicationPool -Name $SearchAppPoolName -Account $SearchAppPoolAccountName -Verbose
}

# Start Services search service instance
Write-host "Start Search Service instances...."
Start-SPEnterpriseSearchServiceInstance $SearchServerName -ErrorAction SilentlyContinue
Start-SPEnterpriseSearchQueryAndSiteSettingsServiceInstance $SearchServerName -ErrorAction SilentlyContinue

Write-Host -ForegroundColor Yellow "Checking if Search Service Application exists"
$ServiceApplication = Get-SPEnterpriseSearchServiceApplication -Identity $SearchServiceName -ErrorAction SilentlyContinue

if (!$ServiceApplication)
{
    Write-Host -ForegroundColor Green "Creating Search Service Application"
    $ServiceApplication = New-SPEnterpriseSearchServiceApplication -Partitioned -Name $SearchServiceName -ApplicationPool $spAppPool.Name
-DatabaseName $DatabaseName
}

Write-Host -ForegroundColor Yellow "Checking if Search Service Application Proxy exists"
$Proxy = Get-SPEnterpriseSearchServiceApplicationProxy -Identity $SearchServiceProxyName -ErrorAction SilentlyContinue

if (!$Proxy)
{
    Write-Host -ForegroundColor Green "Creating Search Service Application Proxy"
    New-SPEnterpriseSearchServiceApplicationProxy -Partitioned -Name $SearchServiceProxyName -SearchApplication $ServiceApplication
}


$ServiceApplication.ActiveTopology
Write-Host $ServiceApplication.ActiveTopology

# Clone the default Topology (which is empty) and create a new one and then activate it
Write-Host "Configuring Search Component Topology...."
$clone = $ServiceApplication.ActiveTopology.Clone()
$SSI = Get-SPEnterpriseSearchServiceInstance -local
New-SPEnterpriseSearchAdminComponent –SearchTopology $clone -SearchServiceInstance $SSI
New-SPEnterpriseSearchContentProcessingComponent –SearchTopology $clone -SearchServiceInstance $SSI
New-SPEnterpriseSearchAnalyticsProcessingComponent –SearchTopology $clone -SearchServiceInstance $SSI
New-SPEnterpriseSearchCrawlComponent –SearchTopology $clone -SearchServiceInstance $SSI

Remove-Item -Recurse -Force -LiteralPath $IndexLocation -ErrorAction SilentlyContinue
mkdir -Path $IndexLocation -Force

New-SPEnterpriseSearchIndexComponent –SearchTopology $clone -SearchServiceInstance $SSI -RootDirectory $IndexLocation
New-SPEnterpriseSearchQueryProcessingComponent –SearchTopology $clone -SearchServiceInstance $SSI
$clone.Activate()

Write-host "Your search service application $SearchServiceName is now ready"