Port Forwarding

Skaffold has built-in support for forwarding ports from exposed Kubernetes resources on your cluster to your local machine when running in dev, debug, deploy, or run modes.

Automatic Port Forwarding

Skaffold supports automatic port forwarding the following classes of resources:

  • user: explicit port-forwards defined in the skaffold.yaml (called user-defined port forwards)
  • services: ports exposed on services deployed by Skaffold.
  • debug: debugging ports as enabled by skaffold debug for Skaffold-built images.
  • pods: all containerPorts on deployed pods for Skaffold-built images.

Skaffold enables certain classes of forwards by default depending on the Skaffold command used. These defaults can be overridden with the --port-forward flag, and port-forwarding can be disabled with --port-forward=off.

Command-line Default modes
skaffold dev user
skaffold dev --port-forward user, services
skaffold dev --port-forward=off no ports forwarded
skaffold debug user, debug
skaffold debug --port-forward user, services, debug (see note below)
skaffold debug --port-forward=off no ports forwarded
skaffold deploy off
skaffold deploy --port-forward user, services
skaffold run off
skaffold run --port-forward user, services

User-Defined Port Forwarding

Users can define additional resources to port forward in the skaffold config, to enable port forwarding for

  • additional resource types supported by kubectl port-forward e.g.Deploymentor ReplicaSet.
  • additional pods running containers which run images not built by Skaffold.

For example:

portForward:
- resourceType: deployment
  resourceName: myDep
  namespace: mynamespace
  port: 8080
  localPort: 9000 # *Optional*

For this example, Skaffold will attempt to forward port 8080 to localhost:9000. If port 9000 is unavailable, Skaffold will forward to a random open port.

Skaffold will run kubectl port-forward on each of these resources in addition to the automatic port forwarding described above. Acceptable resource types include: Service, Pod and Controller resource type that has a pod spec: ReplicaSet, ReplicationController, Deployment, StatefulSet, DaemonSet, Job, CronJob.

Field Values Mandatory
resourceType pod, service, deployment, replicaset, statefulset, replicationcontroller, daemonset, job, cronjob Yes
resourceName Name of the resource to forward. Yes
namespace The namespace of the resource to port forward. No. Defaults to current namespace, or default if no current namespace is defined
port Port is the resource port that will be forwarded. Yes
address Address is the address on which the forward will be bound. No. Defaults to 127.0.0.1
localPort LocalPort is the local port to forward too. No. Defaults to value set for port.

Skaffold will run kubectl port-forward on all user defined resources. kubectl port-forward will select one pod created by that resource to forward too.

For example, forwarding a deployment that creates 3 replicas could look like this:

portForward:
- resourceType: deployment
  resourceName: myDep
  namespace: mynamespace
  port: 8080
  localPort: 9000

portforward_deployment

If you want the port forward to to be available from other hosts and not from the local host only, you can bind the port forward to the address 0.0.0.0:

portForward:
- resourceType: deployment
  resourceName: myDep
  namespace: mynamespace
  port: 8080
  address: 0.0.0.0
  localPort: 9000
Last modified April 14, 2021: release: v1.22.0 (4e67ac7)