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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

Here we are going to reconfigure TLS of Redis in Sentinel Mode. First we are going to deploy a RedisSentinel instance and a Redis instance. Then wer are going to add TLS to them.

Deploy RedisSentinel without TLS :

In this section, we are going to deploy a RedisSentinel instance. Below is the YAML of the RedisSentinel CR that we are going to create,

apiVersion: kubedb.com/v1alpha2
kind: RedisSentinel
metadata:
  name: sen-sample
  namespace: demo
spec:
  version: 6.2.14
  replicas: 3
  storageType: Durable
  storage:
    resources:
      requests:
        storage: 1Gi
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
  terminationPolicy: DoNotTerminate

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

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.12.21/docs/examples/redis/reconfigure-tls/sentinel.yaml
redissentinel.kubedb.com/sen-sample created

Now, wait until sen-sample created has status Ready. i.e,

$ kubectl get redissentinel -n demo
NAME         VERSION   STATUS   AGE
sen-sample   6.2.14     Ready    5m20s

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: 6.2.14
  replicas: 3
  sentinelRef:
    name: sen-sample
    namespace: demo
  mode: Sentinel
  storageType: Durable
  storage:
    resources:
      requests:
        storage: 1Gi
    storageClassName: "standard"
    accessModes:
      - ReadWriteOnce
  terminationPolicy: DoNotTerminate

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

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.12.21/docs/examples/redis/reconfigure-tls/rd-sentinel.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   6.2.14     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/ ClusterIssuer

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

  • 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 create a ca-secret using the certificate files you have just generated. The secret should be created in cert-manager namespace to create the ClusterIssuer.
$ kubectl create secret tls redis-ca \
     --cert=ca.crt \
     --key=ca.key \
     --namespace=cert-manager

Now, create an ClusterIssuer using the ca-secret you have just created. The YAML file looks like this:

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

Apply the YAML file:

$ kubectl create -f https://github.com/kubedb/docs/raw/v2023.12.21/docs/examples/redis/reconfigure-tls/clusterissuer.yaml
clusterissuer.cert-manager.io/redis-ca-issuer created

Create RedisOpsRequest

There are two basic things to keep in mind when securing Redis using TLS in Sentinel Mode.

  • Either Sentinel instance and Redis database both should have TLS enabled or both have TLS disabled.
  • If TLS enabled, both Sentinel instance and Redis database should use the same Issuer. If they are in different namespace, in order to use same issuer, the certificates should be signed using ClusterIssuer

Currently, both Sentinel and Redis is tls disabled. If we want to add TLS to Redis database, we need to give reference to name/namespace of a Sentinel which is tls enabled. If a Sentinel is not found in given name/namespace KubeDB operator will create one.

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:
    sentinel:
      ref:
        name: sen-demo-tls
        namespace: demo
      removeUnusedSentinel: true
    issuerRef:
      apiGroup: cert-manager.io
      name: redis-ca-issuer
      kind: ClusterIssuer
    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.sentinel.ref specifies the new sentinel which will monitor the redis after adding tls. If it does not exist, KubeDB will create one with given issuer.
  • 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/v2023.12.21/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.

Let’s check if new sentinel named sen-demo-tls is created

$ kubectl get redissentinel -n demo
NAME           VERSION   STATUS   AGE
sen-demo-tls   6.2.14     Ready    17m

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: ClusterIssuer
              cert-manager.io/issuer-name: redis-ca-issuer
              cert-manager.io/uri-sans: 

Type:  kubernetes.io/tls

Data
====
ca.crt:   1139 bytes
tls.crt:  1168 bytes
tls.key:  1675 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 sentinel and database. First let’s check the current expiration date of the certificate.

# Check Redis 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 10 05:42:14 2023 GMT

# Check Sentinel Certificate
$ kubectl exec -it -n demo sen-demo-tls-0 -c redissentinel -- bash

root@sen-demo-tls-0:/data# apt-get update; apt-get install openssl;
...

root@sen-demo-tls-0:/data# openssl x509 -in /certs/server.crt -inform PEM -enddate -nameopt RFC2253 -noout
notAfter=May 10 05:41:19 2023 GMT

So, the redis certificate will expire on May 10 05:42:14 2023 GMT and sentinel certificate will expire on notAfter=May 10 05:41:19 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/v2023.12.21/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 10 06:04:12 2023 GMT

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

Create RedisSentinelOpsRequest

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: RedisSentinelOpsRequest
metadata:
  name: sen-ops-rotate
  namespace: demo
spec:
  type: ReconfigureTLS
  databaseRef:
    name: sen-demo-tls
  tls:
    rotateCertificates: true

Here,

  • spec.databaseRef.name specifies that we are performing reconfigure TLS operation on sen-demo-tls sentinel.
  • 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/v2023.12.21/docs/examples/redis/reconfigure-tls/sen-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 redissentinelopsrequest -n demo
Every 2.0s: kubectl get redissentinelopsrequest -n demo
NAME             TYPE             STATUS       AGE
sen-ops-rotate   ReconfigureTLS   Successful   78s

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

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

$ kubectl exec -it -n demo sen-demo-tls-0 -c redissentinel -- 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 10 06:10:43 2023 GMT

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

Remove TLS from the Database

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

Currently, both Sentinel and Redis is tls enabled. If we want to remove TLS from Redis database, we need to give reference to name/namespace of a Sentinel which is tls disabled. If a Sentinel is not found in given name/namespace KubeDB operator will create one.

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:
    sentinel:
      ref:
        name: sen-sample
        namespace: demo
      removeUnusedSentinel: true
    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.sentinel.ref specifies the new sentinel which will monitor the redis after removing tls. If it does not exist, KubeDB will create a sentinel with given name/namespace.
  • 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/v2023.12.21/docs/examples/redis/reconfigure-tls/sen-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    2m5s

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

Let’s check if new sentinel named sen-sample is created

$ kubectl get redissentinel -n demo
NAME         VERSION   STATUS   AGE
sen-sample   6.2.14     Ready    7m56s

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:

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

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

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

# Delete RedisSentinel and RedisSentinelOpsRequest
$ kubectl patch -n demo redissentinel/sen-sample -p '{"spec":{"terminationPolicy":"WipeOut"}}' --type="merge"
redissentinel.kubedb.com/sen-sample patched

$ kubectl delete -n demo redissentinel sen-sample
redissentinel.kubedb.com "sen-sample" deleted

$ kubectl delete -n demo redissentinelopsrequests sen-ops-rotate
redissentinelopsrequest.ops.kubedb.com "sen-ops-rotate" deleted

Next Steps