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Configuring secure communication with Redis

Using the Transport Layer Security (TLS) encryption with Red Hat OpenShift GitOps, you can secure the communication between the Argo CD components and Redis cache and protect the possibly sensitive data in transit.

You can secure communication with Redis by using one of the following configurations:

  • Enable the autotls setting to issue an appropriate certificate for TLS encryption.

  • Manually configure the TLS encryption by creating the argocd-operator-redis-tls secret with a key and certificate pair.

Both configurations are possible with or without the High Availability (HA) enabled.

Prerequisites

  • You have access to the cluster with cluster-admin privileges.

  • You have access to the OpenShift Container Platform web console.

  • Red Hat OpenShift GitOps Operator is installed on your cluster.

Configuring TLS for Redis with autotls enabled

You can configure TLS encryption for Redis by enabling the autotls setting on a new or already existing Argo CD instance. The configuration automatically provisions the argocd-operator-redis-tls secret and does not require further steps. Currently, OpenShift Container Platform is the only supported secret provider.

By default, the autotls setting is disabled.
Procedure

  1. Log in to the OpenShift Container Platform web console.

  2. Create an Argo CD instance with autotls enabled:

    1. In the Administrator perspective of the web console, use the left navigation panel to go to Administration → CustomResourceDefinitions.

    2. Search for argocds.argoproj.io and click ArgoCD custom resource definition (CRD).

    3. On the CustomResourceDefinition details page, click the Instances tab, and then click Create ArgoCD.

    4. Edit or replace the YAML similar to the following example:

      Example Argo CD CR with autotls enabled
      apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: argocd (1)
  namespace: openshift-gitops (2)
spec:
  redis:
    autotls: openshift (3)
  ha:
    enabled: true (4)
      1 The name of the Argo CD instance.
      2 The namespace where you want to run the Argo CD instance.
      3 The flag that enables the autotls setting and creates a TLS certificate for Redis.
      4 The flag value that enables the HA feature. If you do not want to enable HA, do not include this line or set the flag value as false.

      Alternatively, you can enable the autotls setting on an already existing Argo CD instance by running the following command:

      $ oc patch argocds.argoproj.io <instance-name> --type=merge -p '{"spec":{"redis":{"autotls":"openshift"}}}'

    5. Click Create.

    6. Verify that the Argo CD pods are ready and running:

      $ oc get pods -n <namespace> (1)
      1 Specify a namespace where the Argo CD instance is running, for example openshift-gitops.
      Example output with HA disabled
      NAME                                  READY   STATUS    RESTARTS   AGE
argocd-application-controller-0       1/1     Running   0          26s
argocd-redis-84b77d4f58-vp6zm         1/1     Running   0          37s
argocd-repo-server-5b959b57f4-znxjq   1/1     Running   0          37s
argocd-server-6b8787d686-wv9zh        1/1     Running   0          37s

      The HA-enabled TLS configuration requires a cluster with at least three worker nodes. It can take a few minutes for the output to appear if you have enabled the Argo CD instances with HA configuration.
      Example output with HA enabled
      NAME                                       READY   STATUS    RESTARTS   AGE
argocd-application-controller-0            1/1     Running   0          10m
argocd-redis-ha-haproxy-669757fdb7-5xg8h   1/1     Running   0          10m
argocd-redis-ha-server-0                   2/2     Running   0          9m9s
argocd-redis-ha-server-1                   2/2     Running   0          98s
argocd-redis-ha-server-2                   2/2     Running   0          53s
argocd-repo-server-576499d46d-8hgbh        1/1     Running   0          10m
argocd-server-9486f88b7-dk2ks              1/1     Running   0          10m

  3. Verify that the argocd-operator-redis-tls secret is created:

    $ oc get secrets argocd-operator-redis-tls -n <namespace> (1)
    1 Specify a namespace where the Argo CD instance is running, for example openshift-gitops.
    Example output
    NAME                        TYPE                DATA   AGE
argocd-operator-redis-tls   kubernetes.io/tls   2      30s

    The secret must be of the kubernetes.io/tls type and a size of 2.

Configuring TLS for Redis with autotls disabled

You can manually configure TLS encryption for Redis by creating the argocd-operator-redis-tls secret with a key and certificate pair. In addition, you must annotate the secret to indicate that it belongs to the appropriate Argo CD instance. The steps to create a certificate and secret vary for instances with High Availability (HA) enabled.

Procedure

  1. Log in to the OpenShift Container Platform web console.

  2. Create an Argo CD instance:

    1. In the Administrator perspective of the web console, use the left navigation panel to go to Administration → CustomResourceDefinitions.

    2. Search for argocds.argoproj.io and click ArgoCD custom resource definition (CRD).

    3. On the CustomResourceDefinition details page, click the Instances tab, and then click Create ArgoCD.

    4. Edit or replace the YAML similar to the following example:

      Example ArgoCD CR with autotls disabled
      apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: argocd (1)
  namespace: openshift-gitops (2)
spec:
  ha:
    enabled: true (3)
      1 The name of the Argo CD instance.
      2 The namespace where you want to run the Argo CD instance.
      3 The flag value that enables the HA feature. If you do not want to enable HA, do not include this line or set the flag value as false.

    5. Click Create.

    6. Verify that the Argo CD pods are ready and running:

      $ oc get pods -n <namespace> (1)
      1 Specify a namespace where the Argo CD instance is running, for example openshift-gitops.
      Example output with HA disabled
      NAME                                  READY   STATUS    RESTARTS   AGE
argocd-application-controller-0       1/1     Running   0          26s
argocd-redis-84b77d4f58-vp6zm         1/1     Running   0          37s
argocd-repo-server-5b959b57f4-znxjq   1/1     Running   0          37s
argocd-server-6b8787d686-wv9zh        1/1     Running   0          37s

      The HA-enabled TLS configuration requires a cluster with at least three worker nodes. It can take a few minutes for the output to appear if you have enabled the Argo CD instances with HA configuration.
      Example output with HA enabled
      NAME                                       READY   STATUS    RESTARTS   AGE
argocd-application-controller-0            1/1     Running   0          10m
argocd-redis-ha-haproxy-669757fdb7-5xg8h   1/1     Running   0          10m
argocd-redis-ha-server-0                   2/2     Running   0          9m9s
argocd-redis-ha-server-1                   2/2     Running   0          98s
argocd-redis-ha-server-2                   2/2     Running   0          53s
argocd-repo-server-576499d46d-8hgbh        1/1     Running   0          10m
argocd-server-9486f88b7-dk2ks              1/1     Running   0          10m

  3. Create a self-signed certificate for the Redis server by using one of the following options depending on your HA configuration:

    • For the Argo CD instance with HA disabled, run the following command:

      $ openssl req -new -x509 -sha256 \
  -subj "/C=XX/ST=XX/O=Testing/CN=redis" \
  -reqexts SAN -extensions SAN \
  -config <(printf "\n[SAN]\nsubjectAltName=DNS:argocd-redis.<namespace>.svc.cluster.local\n[req]\ndistinguished_name=req") \ (1)
  -keyout /tmp/redis.key \
  -out /tmp/redis.crt \
  -newkey rsa:4096 \
  -nodes \
  -sha256 \
  -days 10
      1 Specify a namespace where the Argo CD instance is running, for example openshift-gitops.
      Example output
      Generating a RSA private key
...............++++
............................++++
writing new private key to '/tmp/redis.key'

    • For the Argo CD instance with HA enabled, run the following command:

      $ openssl req -new -x509 -sha256 \
  -subj "/C=XX/ST=XX/O=Testing/CN=redis" \
  -reqexts SAN -extensions SAN \
  -config <(printf "\n[SAN]\nsubjectAltName=DNS:argocd-redis-ha-haproxy.<namespace>.svc.cluster.local\n[req]\ndistinguished_name=req") \ (1)
  -keyout /tmp/redis-ha.key \
  -out /tmp/redis-ha.crt \
  -newkey rsa:4096 \
  -nodes \
  -sha256 \
  -days 10
      1 Specify a namespace where the Argo CD instance is running, for example openshift-gitops.
      Example output
      Generating a RSA private key
...............++++
............................++++
writing new private key to '/tmp/redis-ha.key'

  4. Verify that the generated certificate and key are available in the /tmp directory by running the following commands:

    $ cd /tmp
    $ ls
    Example output with HA disabled
    ...
redis.crt
redis.key
...
    Example output with HA enabled
    ...
redis-ha.crt
redis-ha.key
...

  5. Create the argocd-operator-redis-tls secret by using one of the following options depending on your HA configuration:

    • For the Argo CD instance with HA disabled, run the following command:

      $ oc create secret tls argocd-operator-redis-tls --key=/tmp/redis.key --cert=/tmp/redis.crt

    • For the Argo CD instance with HA enabled, run the following command:

      $ oc create secret tls argocd-operator-redis-tls --key=/tmp/redis-ha.key --cert=/tmp/redis-ha.crt
      Example output
      secret/argocd-operator-redis-tls created

  6. Annotate the secret to indicate that it belongs to the Argo CD CR:

    $ oc annotate secret argocd-operator-redis-tls argocds.argoproj.io/name=<instance-name> (1)
    1 Specify a name of the Argo CD instance, for example argocd.
    Example output
    secret/argocd-operator-redis-tls annotated

  7. Verify that the Argo CD pods are ready and running:

    $ oc get pods -n <namespace> (1)
    1 Specify a namespace where the Argo CD instance is running, for example openshift-gitops.
    Example output with HA disabled
    NAME                                  READY   STATUS    RESTARTS   AGE
argocd-application-controller-0       1/1     Running   0          26s
argocd-redis-84b77d4f58-vp6zm         1/1     Running   0          37s
argocd-repo-server-5b959b57f4-znxjq   1/1     Running   0          37s
argocd-server-6b8787d686-wv9zh        1/1     Running   0          37s

    It can take a few minutes for the output to appear if you have enabled the Argo CD instances with HA configuration.
    Example output with HA enabled
    NAME                                       READY   STATUS    RESTARTS   AGE
argocd-application-controller-0            1/1     Running   0          10m
argocd-redis-ha-haproxy-669757fdb7-5xg8h   1/1     Running   0          10m
argocd-redis-ha-server-0                   2/2     Running   0          9m9s
argocd-redis-ha-server-1                   2/2     Running   0          98s
argocd-redis-ha-server-2                   2/2     Running   0          53s
argocd-repo-server-576499d46d-8hgbh        1/1     Running   0          10m
argocd-server-9486f88b7-dk2ks              1/1     Running   0          10m