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:

_images/spk_warn.png Important: Cert Manager requires the CRDs prefixed with f5-certmgr-.

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 command output should appear similar to the following:

    f5-cert-manager-0.22.22-0.0.2.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 repo.f5.com/images.

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

    image:
  repository: repo.f5.com/images/cert-manager-controller

webhook:
  image:
    repository: repo.f5.com/images/cert-manager-webhook

cainjector:
  image:
    repository: repo.f5.com/images/cert-manager-cainjector

startupapicheck:
  image:
    repository: repo.f5.com/images/cert-manager-ctl

init_container:
  image:
    repository: repo.f5.com/images

  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: "repo.f5.com/images"

  fluentd:
    host: f5-toda-fluentd.cnf-gateway.svc.cluster.local.

  5. Create a new namespace for the Cert Manager Pods using the following command syntax:

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

    kubectl create ns <namespace>

    For example:

    kubectl 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 <namespace>

    For example:

    helm install f5-cert-manager tar/f5-cert-manager-0.22.22-0.0.2.tgz \
-f cert-manager-values.yaml -n cnf-cert-manager

  7. Verify the status of the Cert Manager Pods:

    kubectl 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:

    kubectl 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:

    kubectl 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:

    kubectl 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:

    kubectl delete secret ca-key-pair -n cnf-cert-manager

    kubectl 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