Egress provides a way for an application deployed on OpenShift to access an external URL, such as http://www.example.com.

Optionally, NetNamespace is used to assign an egress IP address to one or more namespaces, so that all egress traffic from the namespace is using a dedicated IP address. By assigning a specific egress IP address to a namespace, all outbound (egress) requests from applications in the project will come from the dedicated egress IP address, making it easier to find the requests that came from applications in the project. This also makes it possible to have two (or more) different projects share the same egress IP address, as a way to group similar projects together.

An OpenShift route or an Ingress route will provide a URL such as http://route001-project001.apps.openshift.example.com:8080 which is used to route a request onto a service, which is then routed onto a pod, and then to the container in the pod, and finally to the application running in the container.

If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.

The oc get egressnetworkpolicy command can then be used to list the egress network policies that have been created in a project / namespace.

~]$ oc get egressnetworkpolicy
NAME           AGE
egress-rules   115s

The oc describe egressnetworkpolicy command can be used to display egress related configuration. In this example, the egress settings for the project/namespace named foo is displayed. The rules are read in order, which means the deny rule should always be the very last rule.

~]$ oc describe egressnetworkpolicy egress-rules
Name:           egress-rules
Namespace:      foo
Created:        2 minutes ago
Labels:         <none>
Annotations:    <none>
Rule:           Allow to 10.45.6.123/24
Rule:           Allow to www.example.com
Rule:           Deny to 0.0.0.0/0

The oc apply or oc create command with the -f or --filename option can be used to create the egress rules using the template JSON or YAML file.

The oc replace command can be used to replace the egress rules using a new or updated template JSON or YAML file.

The oc edit command can be used to update the egress rules.

oc edit egressnetworkpolicy egress-rules