v4.0.0

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Configuring Port Forwarding

Port-forwarding allows you to access your application on localhost:[PORT] by forwarding the network traffic from a localhost port to a specified port of a container.

When starting the development mode, DevSpace starts port-forwarding as configured in the dev.ports section of the devspace.yaml.

images:
  backend:
    image: john/devbackend
  backend-debugger:
    image: john/debugger
deployments:
- name: app-backend
  component:
    containers:
    - image: john/devbackend
    - image: john/debugger
dev:
  ports:
  - imageName: backend
    forward:
    - port: 8080
      remotePort: 80

Every port-forwarding configuration consists of two parts:

The port option must be unique across your entire ports section, e.g. you can only use the value 8080 once for the port option in your ports section.

Container Selection

The following config options are needed to determine the container to which the traffic should be forwarded.

You can set either labelSelector or imageName. Both options can be combined with the optional namespace option if needed.

dev.ports[*].imageName

The imageName option expects a string with the name of an image from the images section of the devspace.yaml. Using imageName tells DevSpace to select the container based on the referenced image that was last built using DevSpace.

Using imageName is not possible if multiple deployments use the same image that belongs to this imageName referencing the images section of the devspace.yaml.

You cannot use the imageName option in combination with labelSelector.

Example: Select Container by Image

images:
  backend:
    image: john/devbackend
  backend-debugger:
    image: john/debugger
deployments:
- name: app-backend
  component:
    containers:
    - name: container-0
      image: john/devbackend
    - name: container-1
      image: john/debugger
dev:
  ports:
  - imageName: backend
    forward:
    - port: 8080
      remotePort: 80
  - imageName: backend-debugger
    forward:
    - port: 3000

Explanation:

  • The above example defines two images that can be used as imageName: backend and backend-debugger
  • The deployment starts two containers and each of them uses an image from the images section.
  • The imageName option of the first port-forwarding configuration in the dev.ports section references backend. That means DevSpace would select the first container for port-forwarding, as this container uses the image: john/devbackend which belongs to the backend image as defined in the images section.
  • The imageName option of the second port-forwarding configuration in the dev.ports section references backend-debugger. That means DevSpace would select the second container for port-forwarding, as this container uses the image: john/debugger which belongs to the backend-debugger image as defined in the images section.

In consequence, the following port-forwarding processes would be started when using the above config example:

  • localhost:8080 forwards to container-0:80
  • localhost:3000 forwards to container-1:3000

dev.ports[*].labelSelector

The labelSelector option expects a key-value map of strings with Kubernetes labels.

You cannot use the labelSelector option in combination with imageName.

Example: Select Container by Label

images:
  backend:
    image: john/devbackend
  backend-debugger:
    image: john/debugger
deployments:
- name: app-backend
  component:
    containers:
    - name: container-0
      image: john/devbackend
    - name: container-1
      image: john/debugger
dev:
  ports:
  - labelSelector:
      app.kubernetes.io/name: devspace-app
      app.kubernetes.io/component: app-backend
      custom-label: custom-label-value
    forward:
    - port: 8080
      remotePort: 80

Explanation:

  • The labelSelector would select the pod created for the component deployment app-backend.
  • Because containers in the same pod share the same network stack, we do not need to specify which container should be selected.

dev.ports[*].namespace

The namespace option expects a string with a Kubernetes namespace used to select the container from.

It is generally not needed to specify the namespace option because by default, DevSpace uses the default namespace of your current kube-context which is usually the one that has been used to deploy your containers to.

Port Mapping dev.ports[*].forward

The forward section defines which localhost port should be forwarded to the remotePort of the selected container.

By default, remotePort will take the same value as port if remotePort is not explicitly defined.

dev.ports[*].forward[*].port

The port option expects an integer from the range of user ports [1024 - 49151].

Using a port < 1024 will likely to cause problems as these ports are reserved as system ports.

The port option is mandatory.

Example

See "Example: Select Container by Image"

dev.ports[*].forward[*].remotePort

The remotePort option expects an integer from the range of valid ports [0 - 65535].

By default, remotePort has the same value as port if remotePort is not explictly defined.

Example

See "Example: Select Container by Image"

dev.ports[*].forward[*].bindAddress

The bindAddress option expects a valid IP address that the local port should be bound to.

Default Value For bindAddress

bindAddress: "0.0.0.0" # listen on all network interfaces


Useful Commands

devspace add port

Use the convenience command devspace add port [LOCAL_PORT]:[REMOTE_PORT] to tell DevSpace to forward traffic from your computer's [LOCAL_PORT] to the [REMOTE_PORT] of the default component of your application. If no [REMOTE_PORT] is specified, DevSpace will assume that [REMOTE_PORT]=[LOCAL_PORT]. Multiple port mappings can be specified as comma-separated list.

devspace add port 8080:80,3000

The example above would tell DevSpace to forward the local port 8080 to the container port 80 as well as to forward the local port 3000 to the remove container port 3000.

Local ports must be unique across all port forwarding configurations.

Last updated on 9/16/2019
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