Restrict network traffic between workspaces

Restrict traffic between workspace Pods in different user projects by configuring network policies for multitenant isolation. By default, all Pods in an OpenShift cluster can communicate across namespaces.

Before you begin

You have an active oc session with administrative permissions to the OpenShift cluster. See This page is not included, but the link has been rewritten to point to the nearest parent document.Getting started with the CLI.
You have an OpenShift cluster with network restrictions such as multitenant isolation.

About this task

With multitenant isolation, NetworkPolicy objects restrict all incoming traffic to Pods in a user project. However, Pods in the OpenShift Dev Spaces project must still communicate with Pods in user projects.

Procedure

Create an allow-from-openshift-devspaces.yaml file. The allow-from-openshift-devspaces NetworkPolicy allows incoming traffic from the OpenShift Dev Spaces namespace to all Pods in the user project.
```
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
    name: allow-from-openshift-devspaces
spec:
    ingress:
    - from:
        - namespaceSelector:
            matchLabels:
                kubernetes.io/metadata.name: openshift-devspaces
    podSelector: {}
    policyTypes:
    - Ingress
```
where:

kubernetes.io/metadata.name: openshift-devspaces

Selects traffic from the OpenShift Dev Spaces namespace. The default namespace is openshift-devspaces.

podSelector: {}

The empty podSelector selects all Pods in the project.
Apply the allow-from-openshift-devspaces NetworkPolicy to each user project:
```
oc apply -f allow-from-openshift-devspaces.yaml -n <user_namespace>
```
Optional: If you configured multitenant isolation with network policy, create and apply the allow-from-openshift-apiserver and allow-from-workspaces-namespaces NetworkPolicies to openshift-devspaces. The allow-from-openshift-apiserver NetworkPolicy allows incoming traffic from the openshift-apiserver namespace to the devworkspace-webhook-server, enabling webhooks. The allow-from-workspaces-namespaces NetworkPolicy allows incoming traffic from each user project to the che-gateway pod.
1. Create an allow-from-openshift-apiserver.yaml file:
```
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-openshift-apiserver
  namespace: openshift-devspaces
spec:
  podSelector:
    matchLabels:
      app.kubernetes.io/name: devworkspace-webhook-server
  ingress:
    - from:
        - podSelector: {}
          namespaceSelector:
            matchLabels:
              kubernetes.io/metadata.name: openshift-apiserver
  policyTypes:
    - Ingress
```
  where:
  
  namespace: openshift-devspaces
  
  The OpenShift Dev Spaces namespace. The default is openshift-devspaces.
  
  app.kubernetes.io/name: devworkspace-webhook-server
  
  The podSelector only selects devworkspace-webhook-server pods.
2. Create an allow-from-workspaces-namespaces.yaml file:
```
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-from-workspaces-namespaces
  namespace: openshift-devspaces
spec:
  podSelector: {}
  ingress:
    - from:
        - podSelector: {}
          namespaceSelector:
            matchLabels:
              app.kubernetes.io/component: workspaces-namespace
  policyTypes:
    - Ingress
```
  where:
  
  namespace: openshift-devspaces
  
  The OpenShift Dev Spaces namespace. The default is openshift-devspaces.
  
  podSelector: {}
  
  The empty podSelector selects all pods in the OpenShift Dev Spaces namespace.
3. Apply both NetworkPolicies:
```
oc apply -f allow-from-openshift-apiserver.yaml -n openshift-devspaces
oc apply -f allow-from-workspaces-namespaces.yaml -n openshift-devspaces
```

Results

Verify that the NetworkPolicy is applied in the user namespace:
```
oc get networkpolicy -n <user_namespace>
```
Start a workspace and verify that the workspace can communicate with the OpenShift Dev Spaces server.