Transport Layer Security (TLS)¶

The Percona Operator for MySQL uses Transport Layer Security (TLS) cryptographic protocol for the following types of communication:

Internal - communication between Percona XtraDB Cluster instances,
External - communication between the client application and ProxySQL.

The internal certificate is also used as an authorization method.

TLS security can be configured in several ways. By default, the Operator generates long-term certificates automatically if there are no certificate secrets available. Other options are the following ones:

The Operator can use a specifically installed cert-manager, which will automatically generate and renew short-term TLS certificates,
Certificates can be generated manually.

You can also use pre-generated certificates available in the deploy/ssl-secrets.yaml file for test purposes, but we strongly recommend avoiding their usage on any production system!

The following subsections explain how to configure TLS security with the Operator yourself, as well as how to temporarily disable it if needed.

Install and use the cert-manager¶

About the cert-manager¶

A cert-manager is a Kubernetes certificate management controller which is widely used to automate the management and issuance of TLS certificates. It is community-driven, and open source.

When you have already installed cert-manager and deploy the operator, the operator requests a certificate from the cert-manager. The cert-manager acts as a self-signed issuer and generates certificates. The Percona Operator self-signed issuer is local to the operator namespace. This self-signed issuer is created because Percona XtraDB Cluster requires all certificates issued by the same .

Self-signed issuer allows you to deploy and use the Percona Operator without creating a clusterissuer separately.

Installation of the cert-manager¶

The steps to install the cert-manager are the following:

Create a namespace,
Disable resource validations on the cert-manager namespace,
Install the cert-manager.

The following commands perform all the needed actions:

$ kubectl create namespace cert-manager
$ kubectl label namespace cert-manager certmanager.k8s.io/disable-validation=true
$ kubectl apply -f https://github.com/cert-manager/cert-manager/releases/download/v1.16.2/cert-manager.yaml

After the installation, you can verify the cert-manager by running the following command:

$ kubectl get pods -n cert-manager

The result should display the cert-manager and webhook active and running.

Generate certificates manually¶

To generate certificates manually, follow these steps:

Provision a Certificate Authority (CA) to generate TLS certificates
Generate a CA key and certificate file with the server details
Create the server TLS certificates using the CA keys, certs, and server details

The set of commands generate certificates with the following attributes:

Server-pem - Certificate
Server-key.pem - the private key
ca.pem - Certificate Authority

You should generate certificates twice: one set is for external communications, and another set is for internal ones. A secret created for the external use must be added to cr.yaml/spec/secretsName. A certificate generated for internal communications must be added to the cr.yaml/spec/sslInternalSecretName.

$ cat <<EOF | cfssl gencert -initca - | cfssljson -bare ca
{
  "CN": "Root CA",
  "key": {
    "algo": "rsa",
    "size": 2048
  }
}
EOF

$ cat <<EOF | cfssl gencert -ca=ca.pem  -ca-key=ca-key.pem - | cfssljson -bare server
{
  "hosts": [
    "${CLUSTER_NAME}-proxysql",
    "*.${CLUSTER_NAME}-proxysql-unready",
    "*.${CLUSTER_NAME}-pxc"
  ],
  "CN": "${CLUSTER_NAME}-pxc",
  "key": {
    "algo": "rsa",
    "size": 2048
  }
}
EOF

$ kubectl create secret generic cluster1-ssl --from-file=tls.crt=server.pem --
from-file=tls.key=server-key.pem --from-file=ca.crt=ca.pem --
type=kubernetes.io/tls

Update certificates¶

If a cert-manager is used, it should take care of updating the certificates. If you generate certificates manually, you should take care of updating them in proper time.

TLS certificates issued by cert-manager are short-term ones. Starting from the Operator version 1.9.0 cert-manager issues TLS certificates for 3 months, while root certificate is valid for 3 years. This allows to reissue TLS certificates automatically on schedule and without downtime.

Versions of the Operator prior 1.9.0 have used 3 month root certificate, which caused issues with the automatic TLS certificates update. If that’s your case, you can make the Operator update along with the official instruction.

Note

If you use the cert-manager version earlier than 1.9.0, and you would like to avoid downtime while updating the certificates after the Operator update to 1.9.0 or newer version, force the certificates regeneration by a cert-manager.

Check your certificates for expiration¶

First, check the necessary secrets names (cluster1-ssl and cluster1-ssl-internal by default):

$ kubectl get certificate

You will have the following response:

NAME                    READY   SECRET                  AGE
cluster1-ca-cert        True    cluster1-ca-cert        49m
cluster1-ssl            True    cluster1-ssl            49m
cluster1-ssl-internal   True    cluster1-ssl-internal   49m

Optionally you can also check that the certificates issuer is up and running:

$ kubectl get issuer

The response should be as follows:

NAME                     READY   AGE
cluster1-pxc-ca-issuer   True    49m
cluster1-pxc-issuer      True    49m

Now use the following command to find out the certificates validity dates, substituting Secrets names if necessary:

$ {
  kubectl get secret/cluster1-ssl-internal -o jsonpath='{.data.tls\.crt}' | base64 --decode | openssl x509 -inform pem -noout -text | grep "Not After"
  kubectl get secret/cluster1-ssl -o jsonpath='{.data.ca\.crt}' | base64 --decode | openssl x509 -inform pem -noout -text | grep "Not After"
  }

The resulting output will be self-explanatory:

Not After : Sep 15 11:04:53 2021 GMT
Not After : Sep 15 11:04:53 2021 GMT

Update certificates without downtime¶

If you don’t use cert-manager and have created certificates manually, you can follow the next steps to perform a no-downtime update of these certificates if they are still valid.

Note

For already expired certificates, follow the alternative way.

Having non-expired certificates, you can roll out new certificates (both CA and TLS) with the Operator as follows.

Generate a new CA certificate (ca.pem). Optionally you can also generate a new TLS certificate and a key for it, but those can be generated later on step 6.

Get the current CA (ca.pem.old) and TLS (tls.pem.old) certificates and the TLS certificate key (tls.key.old):

$ kubectl get secret/cluster1-ssl-internal -o jsonpath='{.data.ca\.crt}' | base64 --decode > ca.pem.old
$ kubectl get secret/cluster1-ssl-internal -o jsonpath='{.data.tls\.crt}' | base64 --decode > tls.pem.old
$ kubectl get secret/cluster1-ssl-internal -o jsonpath='{.data.tls\.key}' | base64 --decode > tls.key.old

Combine new and current ca.pem into a ca.pem.combined file:
```
$ cat ca.pem ca.pem.old >> ca.pem.combined
```

Create a new Secrets object with old TLS certificate (tls.pem.old) and key (tls.key.old), but a new combined ca.pem (ca.pem.combined):

$ kubectl delete secret/cluster1-ssl-internal
$ kubectl create secret generic cluster1-ssl-internal --from-file=tls.crt=tls.pem.old --from-file=tls.key=tls.key.old --from-file=ca.crt=ca.pem.combined --type=kubernetes.io/tls

The cluster will go through a rolling reconciliation, but it will do it without problems, as every node has old TLS certificate/key, and both new and old CA certificates.
If new TLS certificate and key weren’t generated on step 1, do that now.

Create a new Secrets object for the second time: use new TLS certificate (server.pem in the example) and its key (server-key.pem), and again the combined CA certificate (ca.pem.combined):

$ kubectl delete secret/cluster1-ssl-internal
$ kubectl create secret generic cluster1-ssl-internal --from-file=tls.crt=server.pem --from-file=tls.key=server-key.pem --from-file=ca.crt=ca.pem.combined --type=kubernetes.io/tls

The cluster will go through a rolling reconciliation, but it will do it without problems, as every node already has a new CA certificate (as a part of the combined CA certificate), and can successfully allow joiners with new TLS certificate to join. Joiner node also has a combined CA certificate, so it can authenticate against older TLS certificate.

Create a final Secrets object: use new TLS certificate (server.pmm) and its key (server-key.pem), and just the new CA certificate (ca.pem):

$ kubectl delete secret/cluster1-ssl-internal
$ kubectl create secret generic cluster1-ssl-internal --from-file=tls.crt=server.pem --from-file=tls.key=server-key.pem --from-file=ca.crt=ca.pem --type=kubernetes.io/tls

The cluster will go through a rolling reconciliation, but it will do it without problems: the old CA certificate is removed, and every node is already using new TLS certificate and no nodes rely on the old CA certificate any more.

Update certificates with downtime¶

If your certificates have been already expired (or if you continue to use the Operator version prior to 1.9.0), you should move through the pause - update Secrets - unpause route as follows.

Pause the cluster in a standard way, and make sure it has reached its paused state.

If cert-manager is used, delete issuer and TLS certificates:

$ {
  kubectl delete issuer/cluster1-pxc-ca
  kubectl delete certificate/cluster1-ssl certificate/cluster1-ssl-internal
  }

Delete Secrets to force the SSL reconciliation:

$ kubectl delete secret/cluster1-ssl secret/cluster1-ssl-internal

Check certificates to make sure reconciliation have succeeded.
Unpause the cluster in a standard way, and make sure it has reached its running state.

Keep certificates after deleting the cluster¶

In case of cluster deletion, objects, created for SSL (Secret, certificate, and issuer) are not deleted by default.

If the user wants the cleanup of objects created for SSL, there is a finalizers.delete-ssl option in deploy/cr.yaml: if this finalizer is set, the Operator will delete Secret, certificate and issuer after the cluster deletion event.

Run Percona XtraDB Cluster without TLS¶

Omitting TLS is also possible, but we recommend that you run your cluster with the TLS protocol enabled.

To have TLS protocol disabled (e.g. for demonstration purposes) set the unsafeFlags.tls key to true and set the tls.enabled key to false in the deploy/cr.yaml file:

...
spec:
  ...
  unsafeFlags
    tls: true
    ...
  tls:
    enabled: false

Enabling or disabling TLS on a running cluster¶

You can set tls.enabled Custom Resource option to true or false to enable or disable TLS. However, doing this on a running cluster results in downtime and has the following side effects.

When the cluster is already running and the user switches tls.enabled to false, the Operator pauses the cluster, waits until all Pods are deleted, sets unsafeFlags.tls Custom Resource option to true, deletes TLS secrets, and unpauses the cluster.

Similarly, when the user switches tls.enabled to true, the Operator pauses the cluster, waits until all Pods are deleted, sets unsafeFlags.tls Custom Resource option to false, and unpauses the cluster.

Warning

Don’t change tls.enabled Custom Resource option when the cluster is in the process of enabling or disabling TLS: changing its value will immediately unpause the cluster even though the process has not yet completed.

Get expert help¶

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Last update: 2024-12-19