Chapter 6. Network security

Procedure

1. From OpenShift Cluster Manager, click on the cluster you want to access.
2. Click Open console to navigate to the OpenShift web console.
3. Click on your identity provider and provide your credentials to log in to the cluster.
4. From the administrator perspective, under Networking, click NetworkPolicies.
5. Click Create NetworkPolicy.
6. Provide a name for the policy in the Policy name field.
7. Optional: You can provide the label and selector for a specific pod if this policy applies only to one or more specific pods. If you do not select a specific pod, then this policy will be applicable to all pods on the cluster.
8. Optional: You can block all ingress and egress traffic by using the Deny all ingress traffic or Deny all egress traffic checkboxes.
9. You can also add any combination of ingress and egress rules, allowing you to specify the port, namespace, or IP blocks you want to approve.

10. Add ingress rules to your policy:

    1. Select Add ingress rule to configure a new rule. This action creates a new Ingress rule row with an Add allowed source drop-down menu that enables you to specify how you want to limit inbound traffic. The drop-down menu offers three options to limit your ingress traffic:

       • Allow pods from the same namespace limits traffic to pods within the same namespace. You can specify the pods in a namespace, but leaving this option blank allows all of the traffic from pods in the namespace.
       • Allow pods from inside the cluster limits traffic to pods within the same cluster as the policy. You can specify namespaces and pods from which you want to allow inbound traffic. Leaving this option blank allows inbound traffic from all namespaces and pods within this cluster.
       • Allow peers by IP block limits traffic from a specified Classless Inter-Domain Routing (CIDR) IP block. You can block certain IPs with the exceptions option. Leaving the CIDR field blank allows all inbound traffic from all external sources.
    2. You can restrict all of your inbound traffic to a port. If you do not add any ports then all ports are accessible to traffic.

11. Add egress rules to your network policy:

    1. Select Add egress rule to configure a new rule. This action creates a new Egress rule row with an Add allowed destination"* drop-down menu that enables you to specify how you want to limit outbound traffic. The drop-down menu offers three options to limit your egress traffic:

       • Allow pods from the same namespace limits outbound traffic to pods within the same namespace. You can specify the pods in a namespace, but leaving this option blank allows all of the traffic from pods in the namespace.
       • Allow pods from inside the cluster limits traffic to pods within the same cluster as the policy. You can specify namespaces and pods from which you want to allow outbound traffic. Leaving this option blank allows outbound traffic from all namespaces and pods within this cluster.
       • Allow peers by IP block limits traffic from a specified CIDR IP block. You can block certain IPs with the exceptions option. Leaving the CIDR field blank allows all outbound traffic from all external sources.
    2. You can restrict all of your outbound traffic to a port. If you do not add any ports then all ports are accessible to traffic.

Procedure

1. From the Administrator perspective in the OpenShift Cluster Manager web console, under Networking, click NetworkPolicies.
2. Select the desired network policy to view.
3. In the Network Policy details page, you can view all of the associated ingress and egress rules.

4. Select YAML on the network policy details to view the policy configuration in YAML format.

   Note

   You can only view the details of these policies. You cannot edit these policies.

Procedure

1. From the Administrator perspective in the OpenShift Cluster Manager web console, under Networking, click NetworkPolicies.

2. Use one of the following methods for deleting your network policy:

   • Delete the policy from the Network Policies table:

     1. From the Network Policies table, select the stack menu on the row of the network policy you want to delete and then, click Delete NetworkPolicy.

   • Delete the policy using the Actions drop-down menu from the individual network policy details:

     1. Click on Actions drop-down menu for your network policy.
     2. Select Delete NetworkPolicy from the menu.

Procedure

1. Log in as a user with cluster-admin privileges.

2. Generate the default project template:

   $ oc adm create-bootstrap-project-template -o yaml > template.yaml

3. Use a text editor to modify the generated template.yaml file by adding objects or modifying existing objects.

4. The project template must be created in the openshift-config namespace. Load your modified template:

   $ oc create -f template.yaml -n openshift-config

5. Edit the project configuration resource using the web console or CLI.

   • Using the web console:

     1. Navigate to the Administration Cluster Settings page.
     2. Click Configuration to view all configuration resources.
     3. Find the entry for Project and click Edit YAML.

   • Using the CLI:

     1. Edit the project.config.openshift.io/cluster resource:

        $ oc edit project.config.openshift.io/cluster

6. Update the spec section to include the projectRequestTemplate and name parameters, and set the name of your uploaded project template. The default name is project-request.

   Project configuration resource with custom project template

   apiVersion: config.openshift.io/v1
   kind: Project
   metadata:
   # ...
   spec:
     projectRequestTemplate:
       name: <template_name>
   # ...

7. After you save your changes, create a new project to verify that your changes were successfully applied.

Procedure

1. Edit the default template for a new project by running the following command:

   $ oc edit template <project_template> -n openshift-config

   Replace <project_template> with the name of the default template that you configured for your cluster. The default template name is project-request.

2. In the template, add each NetworkPolicy object as an element to the objects parameter. The objects parameter accepts a collection of one or more objects.

   In the following example, the objects parameter collection includes several NetworkPolicy objects.

   objects:
   - apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: allow-from-same-namespace
     spec:
       podSelector: {}
       ingress:
       - from:
         - podSelector: {}
   - apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: allow-from-openshift-ingress
     spec:
       ingress:
       - from:
         - namespaceSelector:
             matchLabels:
               network.openshift.io/policy-group: ingress
       podSelector: {}
       policyTypes:
       - Ingress
   - apiVersion: networking.k8s.io/v1
     kind: NetworkPolicy
     metadata:
       name: allow-from-kube-apiserver-operator
     spec:
       ingress:
       - from:
         - namespaceSelector:
             matchLabels:
               kubernetes.io/metadata.name: openshift-kube-apiserver-operator
           podSelector:
             matchLabels:
               app: kube-apiserver-operator
       policyTypes:
       - Ingress
   ...

3. Optional: Create a new project to confirm that your network policy objects are created successfully by running the following commands:

   1. Create a new project:

      $ oc new-project <project> 1

      1

      Replace <project> with the name for the project you are creating.

   2. Confirm that the network policy objects in the new project template exist in the new project:

      $ oc get networkpolicy
      NAME                           POD-SELECTOR   AGE
      allow-from-openshift-ingress   <none>         7s
      allow-from-same-namespace      <none>         7s

Procedure

1. Create the following NetworkPolicy objects:

   1. A policy named allow-from-openshift-ingress.

      $ cat << EOF| oc create -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-openshift-ingress
      spec:
        ingress:
        - from:
          - namespaceSelector:
              matchLabels:
                policy-group.network.openshift.io/ingress: ""
        podSelector: {}
        policyTypes:
        - Ingress
      EOF

      Note

      policy-group.network.openshift.io/ingress: "" is the preferred namespace selector label for OVN-Kubernetes.

   2. A policy named allow-from-openshift-monitoring:

      $ cat << EOF| oc create -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-openshift-monitoring
      spec:
        ingress:
        - from:
          - namespaceSelector:
              matchLabels:
                network.openshift.io/policy-group: monitoring
        podSelector: {}
        policyTypes:
        - Ingress
      EOF

   3. A policy named allow-same-namespace:

      $ cat << EOF| oc create -f -
      kind: NetworkPolicy
      apiVersion: networking.k8s.io/v1
      metadata:
        name: allow-same-namespace
      spec:
        podSelector:
        ingress:
        - from:
          - podSelector: {}
      EOF

   4. A policy named allow-from-kube-apiserver-operator:

      $ cat << EOF| oc create -f -
      apiVersion: networking.k8s.io/v1
      kind: NetworkPolicy
      metadata:
        name: allow-from-kube-apiserver-operator
      spec:
        ingress:
        - from:
          - namespaceSelector:
              matchLabels:
                kubernetes.io/metadata.name: openshift-kube-apiserver-operator
            podSelector:
              matchLabels:
                app: kube-apiserver-operator
        policyTypes:
        - Ingress
      EOF

      For more details, see New kube-apiserver-operator webhook controller validating health of webhook.

2. Optional: To confirm that the network policies exist in your current project, enter the following command:

   $ oc describe networkpolicy

   Example output

   Name:         allow-from-openshift-ingress
   Namespace:    example1
   Created on:   2020-06-09 00:28:17 -0400 EDT
   Labels:       <none>
   Annotations:  <none>
   Spec:
     PodSelector:     <none> (Allowing the specific traffic to all pods in this namespace)
     Allowing ingress traffic:
       To Port: <any> (traffic allowed to all ports)
       From:
         NamespaceSelector: network.openshift.io/policy-group: ingress
     Not affecting egress traffic
     Policy Types: Ingress
   
   
   Name:         allow-from-openshift-monitoring
   Namespace:    example1
   Created on:   2020-06-09 00:29:57 -0400 EDT
   Labels:       <none>
   Annotations:  <none>
   Spec:
     PodSelector:     <none> (Allowing the specific traffic to all pods in this namespace)
     Allowing ingress traffic:
       To Port: <any> (traffic allowed to all ports)
       From:
         NamespaceSelector: network.openshift.io/policy-group: monitoring
     Not affecting egress traffic
     Policy Types: Ingress