In addition to Dylan's answer, small adjustment to use with jq.

kubectl get svc -o json | jq '.items[] | {name:.metadata.name, p:.spec.ports[] } | select( .p.nodePort != null ) | "\(.name): localhost:\(.p.nodePort) -> \(.p.port) -> \(.p.targetPort)"'

"web1: localhost:30329 -> 8080 -> 8080"
"web2: localhost:30253 -> 8080 -> 8080"

If the question is about listing which ports have been forwarded from a client host to a pod on a Kubernetes cluster...I am not aware of a

kubectl

/

kubectl port-forward

command for that.

Ultimately, a

kubectl port-forward

ends up calling the

/api/v1/namespaces/{namespace}/pods/{name}/portforward

endpoint and establishes a connection to one of the Kubernetes API servers over the

SPDY

protocol; the kube-apiserver then proxies the connection to a concrete pod. That seems to be the case for when forwarding port(s) with

kubectl port-forward

to a concrete pod, pod selected from a deployment, or pod for a particular Kubernetes service.

Given that the kube-apiserver proxies the connection, examining the network connections on the client or server side with something like

lsof

only shows the port number of the proxy (say, 443 or 8443) for connections to it. On the client side then, using the PID, you can figure out on which port it is listening on - that is the local port that's forwarded.

Also on the client side, just listing all

kubectl

processes using something like

ps -f | grep 'kubectl' | grep 'port-forward'

will list all current port forwards established with

kubectl port-forward

A modification of Oleg Butuzov answer for all namespaces of your cluster.

kubectl get svc --all-namespaces -o json | jq '.items[] | {name:.metadata.name, ns:.metadata.namespace, p:.spec.ports[] } | select( .p.nodePort != null ) | "\(.ns)/\(.name): localhost:\(.p.nodePort) -> \(.p.port) -> \(.p.targetPort)"'
# output
"dbtest/mysql: localhost:31281 -> 3306 -> mysql"

If the question is about the port forwards established from the client to the cluster, this will do:

ps -f | grep 'kubectl' | grep 'port-forward' | awk '{print $10 " " $11}'

if anyone is interested - here is a PS script that will list the processID and the local port it's listening.

param (
[string]$processName="Kubectl",
[string]$commandLinePart
)

# Get the list of processes with the specified name
$processes = Get-Process -Name $processName -ErrorAction SilentlyContinue

if ($processes -eq $null) {
    Write-Output "No process found with the name $processName"
    exit
}

# Iterate through each process and check the command line
foreach ($process in $processes) {
    try {
        $cmdLine = (Get-WmiObject Win32_Process -Filter "ProcessId=$($process.Id)").CommandLine
        if ($cmdLine -like "*$commandLinePart*") {
            Write-Output "Process ID: $($process.Id)"
            Write-Output "Command Line: $cmdLine"

            # Get the TCP port number(s) that the process is listening on
            $netTCPConnections = Get-NetTCPConnection -OwningProcess $process.Id -State Listen
            foreach ($connection in $netTCPConnections) {
                Write-Output "Listening on TCP port: $($connection.LocalPort)"
            }

            if ($netTCPConnections.Count -eq 0) {
                Write-Output "The process is not listening on any TCP ports."
            }
        }
    } catch {
        Write-Output "Failed to retrieve command line or TCP port information for process ID $($process.Id)"
    }
}

Process ID: 84668 Command Line: C:\Users<user>\AppData\Local\Programs\OpenLens\resources\x64\kubectl.exe --kubeconfig C:\Users<user>\AppData\Local\Temp\kubeconfig-7f11e7d63059b39f9 9c18986611c0feb port-forward -n development service/demosite01 0:8080 Listening on TCP port: 1580
Listening on TCP port: 1580

Modified version of Oleg Butuzov's answer, to workaround "Cannot iterate over null" error:

kubectl get svc --all-namespaces -o json | jq '.items[] | select(.spec.ports != null) | {name:.metadata.name, ns:.metadata.namespace, p:.spec.ports[]} | select(.p.nodePort != null) | "\(.ns)/\(.name): localhost:\(.p.nodePort) -> \(.p.port) -> \(.p.targetPort)"' | column -t

Also increased the readability with

column

.