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Reconfigure Redis TLS/SSL (Transport Encryption)

KubeDB supports reconfigure i.e. add, remove, update and rotation of TLS/SSL certificates for existing Redis database via a RedisOpsRequest. This tutorial will show you how to use KubeDB to reconfigure TLS/SSL encryption.

Before You Begin

  • At first, you need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using kind.

  • Install cert-manger v1.0.0 or later to your cluster to manage your SSL/TLS certificates.

  • Now, install KubeDB cli on your workstation and KubeDB operator in your cluster following the steps here.

  • To keep things isolated, this tutorial uses a separate namespace called demo throughout this tutorial.

    $ kubectl create ns demo
    namespace/demo created
    

Note: YAML files used in this tutorial are stored in docs/examples/redis folder in GitHub repository kubedb/docs.

Add TLS to a Redis database

In this tutorial we are going to reconfigure TLS of Redis in Standalone mode. For the Cluster mode, the process is same. A Redis database in Cluster mode needs to be deployed instead of Standalone mode and RedisOpsRequest CR fields are same for both.

Here, We are going to create a Redis database without TLS and then reconfigure the database to use TLS.

Deploy Redis without TLS

In this section, we are going to deploy a Redis Standalone database without TLS. In the next few sections we will reconfigure TLS using RedisOpsRequest CRD. Below is the YAML of the Redis CR that we are going to create,

apiVersion: kubedb.com/v1alpha2
kind: Redis
metadata:
  name: rd-sample
  namespace: demo
spec:
  version: "6.2.5"
  mode: Standalone
  storage:
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
    resources:
      requests:
        storage: 1Gi

Let’s create the Redis CR we have shown above,

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/redis-standalone.yaml
redis.kubedb.com/rd-sample created

Now, wait until redis-standalone has status Ready. i.e,

$ watch kubectl get rd -n demo
Every 2.0s: kubectl get rd -n demo
NAME        VERSION   STATUS   AGE
rd-sample   6.2.5     Ready    88s

Now, we can connect to this database through redis-cli verify that the TLS is disabled.

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash

root@rd-sample-0:/data# redis-cli

127.0.0.1:6379> config get tls-cert-file
1) "tls-cert-file"
2) ""
127.0.0.1:6379> exit
root@rd-sample-0:/data# 

We can verify from the above output that TLS is disabled for this database.

Create Issuer/ StandaloneIssuer

Now, We are going to create an example Issuer that will be used to enable SSL/TLS in Redis. Alternatively, you can follow this cert-manager tutorial to create your own Issuer.

  • Start off by generating a ca certificates using openssl.
$ openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ./ca.key -out ./ca.crt -subj "/CN=ca/O=kubedb"
Generating a RSA private key
................+++++
........................+++++
writing new private key to './ca.key'
-----
  • Now we are going to create a ca-secret using the certificate files that we have just generated.
$ kubectl create secret tls redis-ca \
     --cert=ca.crt \
     --key=ca.key \
     --namespace=demo
secret/redis-ca created

Now, Let’s create an Issuer using the redis-ca secret that we have just created. The YAML file looks like this:

apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: redis-ca-issuer
  namespace: demo
spec:
  ca:
    secretName: redis-ca

Let’s apply the YAML file:

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/issuer.yaml
issuer.cert-manager.io/redis-ca-issuer created

Create RedisOpsRequest

In order to add TLS to the database, we have to create a RedisOpsRequest CRO with our created issuer. Below is the YAML of the RedisOpsRequest CRO that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
  name: rd-add-tls
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: rd-sample
  tls:
    issuerRef:
      name: redis-ca-issuer
      kind: Issuer
      apiGroup: "cert-manager.io"
    certificates:
      - alias: client
        subject:
          organizations:
            - redis
          organizationalUnits:
            - client

Here,

  • spec.databaseRef.name specifies that we are performing reconfigure TLS operation on rd-sample database.
  • spec.type specifies that we are performing ReconfigureTLS on our database.
  • spec.tls.issuerRef specifies the issuer name, kind and api group.
  • spec.tls.certificates specifies the certificates. You can learn more about this field from here.

Let’s create the RedisOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/rd-add-tls.yaml
redisopsrequest.ops.kubedb.com/rd-add-tls created

Verify TLS Enabled Successfully

Let’s wait for RedisOpsRequest to be Successful. Run the following command to watch RedisOpsRequest CRO,

$ kubectl get redisopsrequest -n demo
Every 2.0s: kubectl get redisopsrequest -n demo
NAME           TYPE             STATUS        AGE
rd-add-tls     ReconfigureTLS   Successful    9m

We can see from the above output that the RedisOpsRequest has succeeded.

Now, connect to this database by exec into a pod and verify if tls has been set up as intended.

$ kubectl describe secret -n demo rd-sample-client-cert
Name:         rd-sample-client-cert
Namespace:    demo
Labels:       app.kubernetes.io/component=database
              app.kubernetes.io/instance=rd-sample
              app.kubernetes.io/managed-by=kubedb.com
              app.kubernetes.io/name=redises.kubedb.com
Annotations:  cert-manager.io/alt-names: 
              cert-manager.io/certificate-name: rd-sample-client-cert
              cert-manager.io/common-name: default
              cert-manager.io/ip-sans: 
              cert-manager.io/issuer-group: cert-manager.io
              cert-manager.io/issuer-kind: Issuer
              cert-manager.io/issuer-name: redis-ca-issuer
              cert-manager.io/uri-sans: 

Type:  kubernetes.io/tls

Data
====
ca.crt:   1147 bytes
tls.crt:  1127 bytes
tls.key:  1679 bytes

Now, Lets exec into a redis container and find out the username to connect in a redis shell,

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash

root@rd-sample-0:/data# ls /certs
ca.crt	client.crt  client.key	server.crt  server.key

root@rd-sample-0:/data# redis-cli --tls --cert "/certs/client.crt" --key "/certs/client.key" --cacert "/certs/ca.crt" config get tls-cert-file
1) "tls-cert-file"
2) "/certs/server.crt

root@rd-sample-0:/data# apt-get update; apt-get install openssl;
...

root@rd-sample-0:/data# openssl x509 -in /certs/ca.crt -inform PEM -subject -nameopt RFC2253 -noout
subject=O=kubedb,CN=redis

Now, we can connect using CN=redis,O=kubedb as root to connect to the redis and write some data

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash
# Trying to connect without tls certificates
root@rd-sample-0:/data# redis-cli
127.0.0.1:6379> 
127.0.0.1:6379> set hello world
# Can not write data 
Error: Connection reset by peer 

# Trying to connect with tls certificates
root@rd-sample-0:/data# redis-cli --tls --cert "/certs/client.crt" --key "/certs/client.key" --cacert "/certs/ca.crt"
127.0.0.1:6379> 
127.0.0.1:6379> set hello world
OK
127.0.0.1:6379> exit

Rotate Certificate

Now we are going to rotate the certificate of this database. First let’s check the current expiration date of the certificate.

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash

root@rd-sample-0:/data# apt-get update; apt-get install openssl;
...

root@rd-sample-0:/data# openssl x509 -in /certs/server.crt -inform PEM -enddate -nameopt RFC2253 -noout
notAfter=May  9 09:27:06 2023 GMT

So, the certificate will expire on this time May 9 09:27:06 2023 GMT.

Create RedisOpsRequest

Now we are going to increase it using a RedisOpsRequest. Below is the yaml of the ops request that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
  name: rd-ops-rotate
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: rd-sample
  tls:
    rotateCertificates: true

Here,

  • spec.databaseRef.name specifies that we are performing reconfigure TLS operation on rd-sample database.
  • spec.type specifies that we are performing ReconfigureTLS on our database.
  • spec.tls.rotateCertificates specifies that we want to rotate the certificate of this database.

Let’s create the RedisOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/rd-ops-rotate.yaml
redisopsrequest.ops.kubedb.com/rd-ops-rotate created

Verify Certificate Rotated Successfully

Let’s wait for RedisOpsRequest to be Successful. Run the following command to watch RedisOpsRequest CRO,

$ watch kubectl get redisopsrequest -n demo
Every 2.0s: kubectl get redisopsrequest -n demo
NAME             TYPE             STATUS        AGE
rd-ops-rotate    ReconfigureTLS   Successful    5m5s

We can see from the above output that the RedisOpsRequest has succeeded.

Now, let’s check the expiration date of the certificate.

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash

root@rd-sample-0:/data# apt-get update; apt-get install openssl;
...

root@rd-sample-0:/data# openssl x509 -in /certs/server.crt -inform PEM -enddate -nameopt RFC2253 -noout
notAfter=May  9 10:05:09 2023 GMT

As we can see from the above output, the certificate has been rotated successfully.

Change Issuer/ClusterIssuer

Now, we are going to change the issuer of this database.

  • Let’s create a new ca certificate and key using a different subject CN=ca-update,O=kubedb-updated.
$ openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout ./ca.key -out ./ca.crt -subj "/CN=ca-updated/O=kubedb-updated"
Generating a RSA private key
..............................................................+++++
......................................................................................+++++
writing new private key to './ca.key'
-----
  • Now we are going to create a new ca-secret using the certificate files that we have just generated.
$ kubectl create secret tls redis-new-ca \
     --cert=ca.crt \
     --key=ca.key \
     --namespace=demo
secret/redis-new-ca created

Now, Let’s create a new Issuer using the redis-new-ca secret that we have just created. The YAML file looks like this:

apiVersion: cert-manager.io/v1
kind: Issuer
metadata:
  name: rd-new-issuer
  namespace: demo
spec:
  ca:
    secretName: redis-new-ca

Let’s apply the YAML file:

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/new-issuer.yaml
issuer.cert-manager.io/rd-new-issuer created

Create RedisOpsRequest

In order to use the new issuer to issue new certificates, we have to create a RedisOpsRequest CRO with the newly created issuer. Below is the YAML of the RedisOpsRequest CRO that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
  name: rd-change-issuer
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: rd-sample
  tls:
    issuerRef:
      name: rd-new-issuer
      kind: Issuer
      apiGroup: "cert-manager.io"

Here,

  • spec.databaseRef.name specifies that we are performing reconfigure TLS operation on rd-sample database.
  • spec.type specifies that we are performing ReconfigureTLS on our database.
  • spec.tls.issuerRef specifies the issuer name, kind and api group.

Let’s create the RedisOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/rd-change-issuer.yaml
redisopsrequest.ops.kubedb.com/rd-change-issuer created

Verify Issuer is changed successfully

Let’s wait for RedisOpsRequest to be Successful. Run the following command to watch RedisOpsRequest CRO,

$ kubectl get redisopsrequest -n demo
Every 2.0s: kubectl get redisopsrequest -n demo
NAME                  TYPE             STATUS        AGE
rd-change-issuer      ReconfigureTLS   Successful    4m65s

We can see from the above output that the RedisOpsRequest has succeeded.

Now, Lets exec into a database node and find out the ca subject to see if it matches the one we have provided.

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash

root@rd-sample-0:/data# apt-get update; apt-get install openssl;
...

root@rd-sample-0:/data# openssl x509 -in /certs/ca.crt -inform PEM -subject -nameopt RFC2253 -noout
subject=O=kubedb-updated,CN=ca-updated

We can see from the above output that, the subject name matches the subject name of the new ca certificate that we have created. So, the issuer is changed successfully.

Remove TLS from the Database

Now, we are going to remove TLS from this database using a RedisOpsRequest.

Create RedisOpsRequest

Below is the YAML of the RedisOpsRequest CRO that we are going to create,

apiVersion: ops.kubedb.com/v1alpha1
kind: RedisOpsRequest
metadata:
  name: rd-ops-remove
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: rd-sample
  tls:
    remove: true

Here,

  • spec.databaseRef.name specifies that we are performing reconfigure TLS operation on rd-sample database.
  • spec.type specifies that we are performing ReconfigureTLS on our database.
  • spec.tls.remove specifies that we want to remove tls from this database.

Let’s create the RedisOpsRequest CR we have shown above,

$ kubectl apply -f https://github.com/kubedb/docs/raw/v2023.11.2/docs/examples/redis/reconfigure-tls/rd-ops-remove.yaml
redisopsrequest.ops.kubedb.com/rd-ops-remove created

Verify TLS Removed Successfully

Let’s wait for RedisOpsRequest to be Successful. Run the following command to watch RedisOpsRequest CRO,

$ kubectl get redisopsrequest -n demo
Every 2.0s: kubectl get redisopsrequest -n demo
NAME            TYPE             STATUS        AGE
rd-ops-remove   ReconfigureTLS   Successful    105s

We can see from the above output that the RedisOpsRequest has succeeded.

Now, Lets exec into the database primary node and find out that TLS is disabled or not.

$ kubectl exec -it -n demo rd-sample-0 -c redis -- bash
#
root@rd-sample-0:/data# redis-cli

127.0.0.1:6379> config get tls-cert-file
1) "tls-cert-file"
2) ""
127.0.0.1:6379> exit
root@rd-sample-0:/data# 

So, we can see from the above that, output that tls is disabled successfully.

Cleaning up

To clean up the Kubernetes resources created by this tutorial, run:

$ kubectl patch -n demo redis/rd-sample -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
redis.kubedb.com/rd-sample patched

$ kubectl delete redis -n demo rd-sample
redis.kubedb.com/rd-sample deleted

$ kubectl delete issuer -n demo redis-ca-issuer rd-new-issuer
issuer.cert-manager.io "redis-ca-issuer" deleted
issuer.cert-manager.io "rd-new-issuer" deleted

$ kubectl delete redisopsrequest -n demo rd-add-tls rd-ops-remove rd-ops-rotate rd-change-issuer
redisopsrequest.ops.kubedb.com "rd-add-tls" deleted
redisopsrequest.ops.kubedb.com "rd-ops-remove" deleted
redisopsrequest.ops.kubedb.com "rd-ops-rotate" deleted
redisopsrequest.ops.kubedb.com "rd-change-issuer" deleted

Next Steps