expose_internal_ip_nodeport.adoc

Using a NodePort to Get Traffic into the Cluster

• Overview
• Configuring the Service

Overview

Use NodePorts to expose the service nodePort on all nodes in the cluster.

Note	Using NodePorts requires additional port resources.

A node port exposes the service on a static port on the node IP address.

NodePorts are in the 30000-32767 range by default, which means a NodePort is unlikely to match a service’s intended port (for example, 8080 may be exposed as 31020).

The administrator must ensure the external IPs are routed to the nodes and local firewall rules on all nodes allow access to the open port.

NodePorts and external IPs are independent and both can be used concurrently.

dev_guide/expose_service/expose_internal_ip_service.adoc

Configuring the Service

You specify a port number for the nodePort when you create or modify a service. If you didn’t manually specify a port, system will allocate one for you.

1. Log into the master node.

2. If the project you want to use does not exist, create a new project for your service:

   $ oc new-project <project_name>

   For example:

   $ oc new-project external-ip

3. Edit the service definition to specify spec.type:NodePort and optionally specify a port in the 30000-32767 range.

   apiVersion: v1
   kind: Service
   metadata:
     name: mysql
     labels:
       name: mysql
   spec:
     type: NodePort
     ports:
       - port: 3306
         nodePort: 30036
         name: http
     selector:
       name: mysql

4. Run the following command to create the service:

   $ oc create -f <file_name>

   For example:

   $ oc create -f mysql.yaml

5. Run the following command to see that the new service is created:

   $ oc get svc
   
   NAME             CLUSTER_IP       EXTERNAL_IP   PORT(S)                      AGE
   mysql            172.30.89.219    <none>        3306:30036/TCP               2m

   Note that the external IP is listed as <none> and the node ports are listed.

You should be able to access the service using the <NodeIP>:<NodePort> address.