Deploy a MySQL Cluster with User-Provided TLS on KubeBlocks

This guide explains how to deploy a MySQL cluster with user-provided TLS certificates using KubeBlocks. By supplying your own certificates, you have full control over the security configuration for encrypted communication between the MySQL client and server. This guide covers generating certificates, deploying the cluster, and verifying the secure connection.

Prerequisites

Before proceeding, ensure the following:

• Environment Setup:
  • A Kubernetes cluster is up and running.
  • The kubectl CLI tool is configured to communicate with your cluster.
  • KubeBlocks CLI and KubeBlocks Operator are installed. Follow the installation instructions here.
• Namespace Preparation: To keep resources isolated, create a dedicated namespace for this tutorial:

kubectl create ns demo
namespace/demo created

Generating Certificates

To enable TLS encryption, you will need to provide a Certificate Authority (CA), a server certificate, and a private key. Follow these steps to generate these using OpenSSL:

1. Generate the Root Certificate (CA)

# Create the CA private key (password optional)
openssl genrsa -aes256 -out ca-key.pem 4096

# Generate a self-signed root certificate (valid for 10 years)
openssl req -x509 -new -nodes -key ca-key.pem -sha256 -days 3650 -out ca.pem
# Enter the required information (e.g., Common Name can be "MySQL Root CA")

2. Generate the Server Certificate & Key

# Generate the server private key
openssl genrsa -out server-key.pem 4096

# Create a Certificate Signing Request (CSR)
openssl req -new -key server-key.pem -out server-req.pem
# Enter server identification details, such as:
# Common Name (CN) = Server domain name or IP (must match the MySQL server address!)

# Sign the server certificate with the CA (valid for 10 years)
openssl x509 -req -in server-req.pem -CA ca.pem -CAkey ca-key.pem -CAcreateserial -out server-cert.pem -days 3650 -sha256

3. Verify the Certificates Verify that the server certificate is valid and signed by the CA:

# Verify the server certificate
openssl verify -CAfile ca.pem server-cert.pem

Expected Output:

server-cert.pem: OK

Create Kubernetes Secrets

Store the generated certificates and keys in a Kubernetes Secret to make them accessible to your MySQL cluster:

kubectl create secret generic mysql-tls-secret \
  --namespace=demo \
  --from-file=ca.crt=ca.pem \
  --from-file=tls.crt=server-cert.pem \
  --from-file=tls.key=server-key.pem \
  --type=kubernetes.io/tls

This secret contains the CA, server certificate, and private key required to enable mTLS on the MySQL cluster.

Deploying the MySQL Semi-Synchronous Cluster

KubeBlocks uses a declarative approach for managing MySQL clusters. Below is an example configuration for deploying a MySQL cluster with 2 nodes (1 primary, 1 replicas) in semi-synchronous mode with user-provided TLS certificates:

kubectl apply -f - <<EOF
apiVersion: apps.kubeblocks.io/v1
kind: Cluster
metadata:
  name: example-mysql-cluster
  namespace: demo
spec:
  clusterDef: mysql
  topology: semisync
  terminationPolicy: Delete
  componentSpecs:
    - name: mysql
      serviceVersion: 8.0.35
      replicas: 2
      tls: true
      issuer:
        name: UserProvided
        secretRef:
          name: mysql-tls-secret
          namespace: demo
          ca: ca.crt
          cert: tls.crt
          key: tls.key
      resources:
        limits:
          cpu: '0.5'
          memory: 0.5Gi
        requests:
          cpu: '0.5'
          memory: 0.5Gi
      volumeClaimTemplates:
        - name: data
          spec:
            storageClassName: ""
            accessModes:
              - ReadWriteOnce
            resources:
              requests:
                storage: 20Gi
EOF

Configuration Highlights:

• tls: true: Enables TLS encryption for secure communication.
• issuer.name: UserProvided: Specifies that user-provided certificates are being used.
• secretRef: Links the cluster to the Kubernetes Secret containing the certificates.

Verifying the Deployment

Monitor the cluster status until it transitions to the Running state:

kubectl get cluster -n demo -w

Expected Output:

NAME                    CLUSTER-DEFINITION   TERMINATION-POLICY   STATUS    AGE
example-mysql-cluster   mysql                Delete               Running   11m

Connect to MySQL Cluster

KubeBlocks automatically creates a secret containing the MySQL root credentials. Retrieve the credentials with the following commands:

1. Retrieve the root username:

kubectl get secrets -n demo example-mysql-cluster-mysql-account-root -o jsonpath='{.data.username}' | base64 -d

Expected Output:

root

2. Retrieve the root password:

kubectl get secrets -n demo example-mysql-cluster-mysql-account-root -o jsonpath='{.data.password}' | base64 -d

Expected Output:

D0o5P43S8G

Use the MySQL client with the '--ssl-mode=REQUIRED' option to enforce TLS during the connection:

kubectl exec -it -n demo example-mysql-cluster-mysql-0 -c mysql -- mysql -h example-mysql-cluster-mysql.demo.svc.cluster.local -uroot -pD0o5P43S8G --ssl-mode=REQUIRED

After connecting, verify that TLS is being used by running the STATUS command in the MySQL shell:

mysql> STATUS;
--------------

SSL:			Cipher in use is TLS_AES_256_GCM_SHA384

If you see SSL information in the output, the connection is successfully encrypted using TLS.

Cleanup

Remove all resources after testing:

kubectl delete cluster example-mysql-cluster -n demo
kubectl delete secret mysql-tls-secret -n demo
kubectl delete ns demo

Summary

In this guide, you learned how to:

• Generate a self-signed CA and server certificates using OpenSSL.
• Store the certificates in a Kubernetes Secret.
• Deploy a MySQL cluster with TLS encryption using KubeBlocks.
• Connect to the MySQL cluster securely using TLS and verify the connection.

Using TLS ensures secure communication between the MySQL client and server, protecting sensitive data in transit. By following these steps, you can easily set up and manage a secure MySQL cluster on Kubernetes using KubeBlocks.