CNFs Cert Manager

Overview

The Cloud-Native Network Functions (CNFs) Pods communicate over secure channels using the gRPC (remote procedure call) framework. To establish secure gRPC communication, SSL/TLS keys and certificates must be generated in the cluster. As an added layer of security, and to avoid service disruptions that may occur due to expired SSL/TLS certificates, a rotation schedule should be implemented, regenerating SSL/TLS certificates at specified intervals. The CNFs Certificate Manager integrates with a cluster Certificate Authority (CA), to provide the CNFs Pods with CA signed certificates at a regularly scheduled interval.

This document guides you through installing the CNFs Cert Manager, and generating the required SSL/TLS certificates and keys.

_images/spk_info.png Note: The gRPC channel is established over TCP service port 8750.

CA signing certificate

To sign CNFs Pod certificates, a self-signed certificate authority (CA) signing certificate and key (keypair) can be generated when installing the CNFs Cert Manager. The CA signing keypair is installed in the cluster as a Secret, and will be referenced by a Kubernetes ClusterIssuer object. You can also provide a custom CA and specify the secret name in values yaml file. When the Cert Manager generates certificate signing requests (CSRs) for the CNFs Pods, it will use this CA to sign and return new Pod Certificates across all cluster namespaces.

Pod certificates

All communication endpoints will generate Certificate Signing Request (CSR) and receive a Certificate object when the Pod is installed. The Cert Manager will rotate, or generate new CSRs, based on the duration parameter set in the Pod’s Certificate object. See Rotation schedules in the next section.

Rotation schedules

The table below lists the rotation schedule for each of the CNFs Pods.

Pod Rotation
f5ingress 1 hour
f5-tmm 1 hour
f5-cwc 1 hour
f5-rabbit 1 hour
f5-afm 360 days*
f5-ipsd 1 hour
otel-collector 1 hour
f5-ipsd 1 hour
f5-fluentd 360 days*
f5-dssm-db 1 hour
f5-dssm-sentinel 360 days*

*Cert rotation not supported.

Cluster namespace

It is recommended to install Cert Manager in a dedecated namespace, but it can run in any namespace. In this document, Cert Manager will install to the cnf-cert-manager namespace. As mentioned earlier, Cert Manager uses the ClusterIssuer object to sign certificate requests across all cluster namespaces. Prior to installing the Cert Manager in a new namespace, refer to the Changing namespaces section of this document.

Requirements

Ensure you have:

Important: Cert Manager requires the CRDs prefixed with f5-certmgr- provided in the f5-cnf-crds-n6lan tarball.

Procedures

Cert Manager

Use the following steps to install the CNFs Cert Manager Pods.

  1. Change into the directory containing the latest CNFs Software, and obtain the f5-cert-manager Helm chart version:

    In this example, the CNF files are in the cnfinstall directory:

    cd cnfinstall
    
    ls -1 tar | grep f5-cert-manager
    

    The example output should appear similar to the following:

    f5-cert-manager-1.2.0.tgz
    
  2. Create a Helm values file named cert-manager-values.yaml, and set the image.repository parameters. In the example below, Helm pulls the Cert Manager images from registry.com.

    Important: Due to ID 1251997, the first four image.repository parameters must include the uploaded image name.

    image:
      repository: registry.com/cert-manager-controller
    
    webhook:
      image:
        repository: registry.com/cert-manager-webhook
    
    cainjector:
      image:
        repository: registry.com/cert-manager-cainjector
    
    startupapicheck:
      image:
        repository: registry.com/cert-manager-ctl
    
    init_container:
      image:
        repository: registry.com
    
  3. In cert-manager-values.yaml file set the serviceAccount.create parameter:

    Note: The serviceAccount will not be created by default.

    serviceAccount:
      create: false
      name: default
    
  4. If you enabled the Fluentd Logging collector, set the following parameters:

    Note: Set the image.repository parameter to your local container registry.

    logging_sidecar:
      enabled: true
      image:
        repository: "registry.com"
    
      fluentd:
        host: f5-toda-fluentd.cnf-gateway.svc.cluster.local.
    
  5. Create a new Project for the Cert Manager Pods using the following command syntax:

    Note: A new Project is not required, and used only for easier Pod management.

    oc create ns <project name>
    

    For example:

    oc create ns cnf-cert-manager
    
  6. Install the Cert Manager Pods using the following command syntax:

    helm install <release> tar/<helm-chart>.tgz \
    -f <values>.yaml -n <project>
    

    For example:

    helm install f5-cert-manager tar/f5-cert-manager-1.2.0.tgz \
    -f cert-manager-values.yaml -n cnf-cert-manager
    
  7. Verify the status of the Cert Manager Pods:

    oc get pods -n cnf-cert-manager
    

    In this example, the f5-cert-manager, f5-cert-manager-cainjector, and f5-cert-manager-webhook are Running.

    NAME                                          READY   STATUS    
    f5-cert-manager-cainjector-5cfbf4ff75-drmh7   1/1     Running   
    f5-cert-manager-cbfc74b4d-kskjx               1/1     Running   
    f5-cert-manager-webhook-58bf4b7b76-bcn4p      1/1     Running   
    
  8. Verify the status of the ClusterIssuer:

    oc get clusterissuer -n cnf-cert-manager
    

    In this example, the ClusterIssuer is READY:

    NAME                  READY
    default-cert-issuer   True 
    

OTEL Collectors

The OTEL Collectors receive data from the CNFs Pods and forward it to 3rd party visualization applications such as Prometheus. Cert Manager creates SSL/TLS certificates for the receiving side of the OTEL Collectors, but not for the sending side. You can utilize Cert Manager to create required certificates for OTEL to communicate with third party applications such as Prometheus. You can also use the steps below to manually create Kubernetes Secrets instead of using Cert Manager.

  1. Copy the OTEL Certificate objects into a YAML file:

    apiVersion: cm.f5co.k8s.f5net.com/v1
    kind: Certificate
    metadata:
      name: external-otelsvr
    spec:
      subject:
        countries:
          - US
        provinces:
          - Washington
        localities:
          - Seattle
        organizations:
          - F5 Networks
        organizationalUnits:
          - PD
      emailAddresses:
        - clientcert@f5net.com
      commonName: f5net.com
      # SecretName is the name of the secret resource that will be automatically created and managed by this Certificate resource.
      # It will be populated with a private key and certificate, signed by the denoted issuer.
      secretName: external-otelsvr-secret
      # IssuerRef is a reference to the issuer for this certificate.
      issuerRef:
        name: default-cert-issuer
        kind: ClusterIssuer
      # Lifetime of the Certificate is 1 hour, not configurable
      duration: 8640h
      privateKey:
        rotationPolicy: Always
        encoding: PKCS1
        algorithm: RSA
        size: 4096
      revisionHistoryLimit: 10
    ---
    apiVersion: cm.f5co.k8s.f5net.com/v1
    kind: Certificate
    metadata:
      name: external-f5ingotelsvr
    spec:
      subject:
        countries:
          - US
        provinces:
          - Washington
        localities:
          - Seattle
        organizations:
          - F5 Networks
        organizationalUnits:
          - PD
      emailAddresses:
        - clientcert@f5net.com
      commonName: f5net.com
      # SecretName is the name of the secret resource that will be automatically created and managed by this Certificate resource.
      # It will be populated with a private key and certificate, signed by the denoted issuer.
      secretName: external-f5ingotelsvr-secret
      # IssuerRef is a reference to the issuer for this certificate.
      issuerRef:
        name: default-cert-issuer
        kind: ClusterIssuer
      # Lifetime of the Certificate is 1 hour, not configurable
      duration: 8640h
      privateKey:
        rotationPolicy: Always
        encoding: PKCS1
        algorithm: RSA
        size: 4096
      revisionHistoryLimit: 10
    
  2. Install the Certificate objects to the OTEL Collector namespace:

    In this example, the Certificates install to the cnf-gateway namespace:

    oc apply -f otel-certificates.yaml -n cnf-gateway
    
  3. The output should indicate the Certificates are created:

    certificate.cm.f5co.k8s.f5net.com/external-otelsvr created
    certificate.cm.f5co.k8s.f5net.com/external-f5ingotelsvr created
    
  4. If the Prometheus scheme parameter is set to https (the default is http), you must also set the insecure_skip_verify parameter set to true. View the example ConfigMap template here.

  5. Continue to the Next steps section.

Next steps

Continue with the next step of the installation process described in the Getting Started guide:

  1. Fluentd Logging - Required: Centralize logging data sent from each of the CNF Pods.
  2. OTEL Collectors - Optional: Collect and view statistics from the CNFs Pods.
  3. dSSM Database - Optional: Store session-state data for the AFM and TMM Pods.
  4. CNFs CWC - Required: Install the Cluster Wide Controller to enable gathering CNFs software telemetry.

Changing Namespaces

Prior to reinstalling the CNFs Cert Manager to a different namespace, ensure you delete the currently installed Secrets.

  1. Uninstall the Cert Manager:

    helm uninstall <release> -n <namespace>
    

    In this example, the Cert Manager release named f5-certificate-manager is in the cnf-cert-manager namespace.

    helm uninstall f5-cert-manager -n cnf-cert-manager 
    
  2. List the Cert Manager Secrets:

    oc get secrets -n cnf-cert-manager
    
    NAME                         TYPE                DATA
    ca-key-pair                  kubernetes.io/tls   2 
    f5-cert-manager-webhook-ca   Opaque              3
    
  3. Delete the Secrets:

    oc delete secret ca-key-pair -n cnf-cert-manager
    
    oc delete secret f5-cert-manager-webhook-ca -n cnf-cert-manager
    

    The command output should indicate the Secret is deleted.

    secret "ca-key-pair" deleted
    
    secret "f5-cert-manager-webhook-ca" deleted
    

Feedback

Provide feedback to improve this document by emailing cnfdocs@f5.com.

Supplemental Information