When configuring vSphere Replication between 2 vCenter Servers, you need to add a dedicated VMKernel to each host in the source & target vCEnter Server clusters. Depending on the number of hosts per cluster, this can be a time-consuming manual task. Here is a quick script leveraging PowerCLI to retrieve the hosst from a specified cluster and loop through them adding a dedicated vSphere Replication VMKernel.

#Source VC vmks
$vCenterServer = "sfo-m01-vc01.sfo.rainpole.io"
$vCenterServerUser = "administrator@vsphere.local"
$vCenterServerPassword = "VMw@re1!VMw@re1!"
$clusterName = "sfo-m01-cl01"
$PortGroupName = "sfo-m01-cl01-vds01-pg-vlr"
$VLANID = 1116
$VSwitch = "sfo-m01-cl01-vds01"
$VMKIP = "10.11.16."  # last octet will be incremented
$lastOctetStart = 101
$SubnetMask = "255.255.255.0"
$mtu = 9000

# Connect to vCenter
Connect-VIServer -Server $vCenterServer -user $vCenterServerUser -password $vCenterServerPassword

# Get Esxi hosts in cluster
$ESXiHosts = Get-cluster -name $clusterName | Get-VMHost

# Loop through each host and add an adapter with vSphere Replication Services enabled
$index = $lastOctetStart
foreach ($ESXi in $ESXiHosts) {
    Write-Host "Processing host: $ESXi"

# Define VMkernel IP for this host
    $VMKIPAddress = "$VMKIP$index"
    $index++

# Add VMkernel adapter
    Write-Host "Adding VMkernel adapter $VMKIPAddress to $ESXi"
    $vmk = New-VMHostNetworkAdapter -VMHost $ESXi -VirtualSwitch $VSwitch -PortGroup $PortGroupName -IP $VMKIPAddress -SubnetMask $SubnetMask -VMotionEnabled $false -mtu $mtu
    $vnicMgr = Get-View -Id $ESXi.ExtensionData.ConfigManager.VirtualNicManager
    $vnicMgr.SelectVnicForNicType('vSphereReplication',$vmk.Name)
$vnicMgr.SelectVnicForNicType('vSphereReplicationNFC',$vmk.Name)

    Write-Host "VMkernel adapter added successfully on $ESXi"
}

# Disconnect from vCenter
Disconnect-VIServer -Confirm:$false