Certificates ============ CloudNativePG has been designed to natively support TLS certificates. In order to set up a ``Cluster`` , the operator requires: - a server Certification Authority (CA) certificate - a server TLS certificate signed by the server Certification Authority - a client Certification Authority certificate - a streaming replication client certificate generated by the client Certification Authority .. Note:: You can find all the secrets used by the cluster and their expiration dates in the cluster's status. CloudNativePG is very flexible when it comes to TLS certificates, and primarily operates in two modes: 1. :ref:`**operator managed** <#operator-managed-mode>` : certificates are internally managed by the operator in a fully automated way, and signed using a CA created by CloudNativePG 2. :ref:`**user provided** ` : certificates are generated outside the operator and imported in the cluster definition as secrets - CloudNativePG integrates itself with cert-manager (see examples below) You can also choose a hybrid approach, where only part of the certificates is generated outside CNPG. Operator managed mode --------------------- By default, the operator generates a single Certification Authority and uses it for both client and server certificates, which are then managed and renewed automatically. Server Certificates ^^^^^^^^^^^^^^^^^^^ Server CA Secret ^^^^^^^^^^^^^^^^ The operator generates a self-signed CA and stores it in a generic secret containing the following keys: - ``ca.crt`` : CA certificate used to validate the server certificate, used as ``sslrootcert`` in clients’ connection strings. - ``ca.key`` : the key used to sign Server SSL certificate automatically Server TLS Secret ^^^^^^^^^^^^^^^^^ The operator uses the generated self-signed CA to sign a server TLS certificate, stored in a Secret of type ``kubernetes.io/tls`` and configured to be used as ``ssl_cert_file`` and ``ssl_key_file`` by the instances so that clients can verify their identity and connect securely. Server alternative DNS names ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ You can specify DNS server alternative names that will be part of the generated server TLS secret in addition to the default ones. Client Certificates ^^^^^^^^^^^^^^^^^^^ Client CA Secret ^^^^^^^^^^^^^^^^ The same self-signed CA as the Server CA is used by default. The public part will be passed as ``ssl_ca_file`` to all the instances in order to be able to verify client certificates it signed. The private key will be stored in the same secret and used to sign Client certificates generated by the ``kubectl cnpg`` plugin. Client streaming_replica Certificate ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The operator uses the generated self-signed CA to sign a client certificate for the user ``streaming_replica`` , storing it in a Secret of type ``kubernetes.io/tls`` . This certificate will be passed as ``sslcert`` and ``sslkey`` in replicas’ connection strings, to allow securely connecting to the primary instance. User-provided certificates mode ------------------------------- .. _server-certificates-1: Server Certificates ^^^^^^^^^^^^^^^^^^^ If required, you can also provide the two server certificates, generating them using a separate component such as `cert-manager `_ . In order to use a custom server TLS certificate for a Cluster, you must specify the following parameters: - ``serverTLSSecret`` : the name of a Secret of type ``kubernetes.io/tls`` , containing the server TLS certificate. It must contain both the standard ``tls.crt`` and ``tls.key`` keys. - ``serverCASecret`` : the name of a Secret containing the ``ca.crt`` key. .. Note:: The operator will still create and manage the two secrets related to client certificates. .. Note:: If you want ConfigMaps and Secrets to be **automatically** reloaded by instances, you can add a label with key `cnpg.io/reload` to it, otherwise you will have to reload the instances using the `kubectl cnpg reload` subcommand. See below for a complete example. Example ^^^^^^^ Given the following files: - ``server-ca.crt`` : the certificate of the CA that signed the server TLS certificate. - ``server.crt`` : the certificate of the server TLS certificate. - ``server.key`` : the private key of the server TLS certificate. Create a secret containing the CA certificate: :: kubectl create secret generic my-postgresql-server-ca \ --from-file=ca.crt=./server-ca.crt Create a secret with the TLS certificate: :: kubectl create secret tls my-postgresql-server \ --cert=./server.crt --key=./server.key Create a ``Cluster`` referencing those secrets: .. code:: bash kubectl apply -f - <`_ to set up a self-signed CA and generate the needed TLS server certificate: .. code:: yaml - -- apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: selfsigned-issuer spec: selfSigned: {} - -- apiVersion: v1 kind: Secret metadata: name: my-postgres-server-cert labels: cnpg.io/reload: "" - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: my-postgres-server-cert spec: secretName: my-postgres-server-cert usages: - server auth dnsNames: - cluster-example-lb.internal.mydomain.net - cluster-example-rw - cluster-example-rw.default - cluster-example-rw.default.svc - cluster-example-r - cluster-example-r.default - cluster-example-r.default.svc - cluster-example-ro - cluster-example-ro.default - cluster-example-ro.default.svc issuerRef: name: selfsigned-issuer kind: Issuer group: cert-manager.io A Secret named ``my-postgres-server-cert`` is created by cert-manager, containing all the needed files and can be referenced from a Cluster as follows: .. code:: yaml apiVersion: postgresql.cnpg.io/v1 kind: Cluster metadata: name: cluster-example spec: instances: 3 certificates: serverTLSSecret: my-postgres-server-cert serverCASecret: my-postgres-server-cert storage: size: 1Gi You can find a complete example using cert-manager to manage both server and client CA and certificates in the :: apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: selfsigned-issuer spec: selfSigned: {} - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: server-ca spec: isCA: true commonName: my-selfsigned-server-ca secretName: server-ca-key-pair privateKey: algorithm: ECDSA size: 256 issuerRef: name: selfsigned-issuer kind: Issuer group: cert-manager.io - -- apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: server-ca-issuer spec: ca: secretName: server-ca-key-pair - -- apiVersion: v1 kind: Secret metadata: name: my-postgres-server-cert labels: cnpg.io/reload: "" - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: my-postgres-server-cert spec: secretName: my-postgres-server-cert usages: - server auth dnsNames: - cluster-example-lb.internal.mydomain.net - cluster-example-rw - cluster-example-rw.default - cluster-example-rw.default.svc - cluster-example-r - cluster-example-r.default - cluster-example-r.default.svc - cluster-example-ro - cluster-example-ro.default - cluster-example-ro.default.svc issuerRef: name: server-ca-issuer kind: Issuer group: cert-manager.io - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: client-ca spec: isCA: true commonName: my-selfsigned-client-ca secretName: client-ca-key-pair privateKey: algorithm: ECDSA size: 256 issuerRef: name: selfsigned-issuer kind: Issuer group: cert-manager.io - -- apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: client-ca-issuer spec: ca: secretName: client-ca-key-pair - -- apiVersion: v1 kind: Secret metadata: name: my-postgres-client-cert labels: cnpg.io/reload: "" - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: my-postgres-client-cert spec: secretName: my-postgres-client-cert usages: - client auth commonName: streaming_replica issuerRef: name: client-ca-issuer kind: Issuer group: cert-manager.io - -- apiVersion: postgresql.cnpg.io/v1 kind: Cluster metadata: name: cluster-example spec: instances: 3 certificates: serverTLSSecret: my-postgres-server-cert serverCASecret: my-postgres-server-cert clientCASecret: my-postgres-client-cert replicationTLSSecret: my-postgres-client-cert storage: size: 1Gi deployment manifest. Client Certificate ^^^^^^^^^^^^^^^^^^ If required, you can also provide the two client certificates, generating them using a separate component such as `cert-manager `_ or `hashicorp vault `_ . In order to use a custom CA to verify client certificates for a Cluster, you must specify the following parameters: - ``replicationTLSSecret`` : the name of a Secret of type ``kubernetes.io/tls`` , containing the client certificate for user ``streaming_replica`` . It must contain both the standard ``tls.crt`` and ``tls.key`` keys. - ``clientCASecret`` : the name of a Secret containing the ``ca.crt`` key of the CA that should be used to verify client certificate. .. Note:: The operator will still create and manage the two secrets related to server certificates. .. Note:: As the Cluster is not in control of the client CA secret key, client certificates can not be generated using `kubectl cnpg certificate` anymore. .. Note:: If you want ConfigMaps and Secrets to be **automatically** reloaded by instances, you can add a label with key `cnpg.io/reload` to it, otherwise you will have to reload the instances using the `kubectl cnpg reload` subcommand. .. _cert-manager-example-1: Cert-manager Example ^^^^^^^^^^^^^^^^^^^^ Here a simple example about how to use `cert-manager `_ to set up a self-signed CA and generate the needed TLS server certificate: .. code:: yaml - -- apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: selfsigned-issuer spec: selfSigned: {} - -- apiVersion: v1 kind: Secret metadata: name: my-postgres-client-cert labels: cnpg.io/reload: "" - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: my-postgres-client-cert spec: secretName: my-postgres-client-cert usages: - client auth commonName: streaming_replica issuerRef: name: selfsigned-issuer kind: Issuer group: cert-manager.io A Secret named ``my-postgres-client-cert`` is created by cert-manager, containing all the needed files and can be referenced from a Cluster as follows: .. code:: yaml apiVersion: postgresql.cnpg.io/v1 kind: Cluster metadata: name: cluster-example spec: instances: 3 certificates: clientCASecret: my-postgres-client-cert replicationTLSSecret: my-postgres-client-cert storage: size: 1Gi You can find a complete example using cert-manager to manage both server and client CA and certificates in the :: apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: selfsigned-issuer spec: selfSigned: {} - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: server-ca spec: isCA: true commonName: my-selfsigned-server-ca secretName: server-ca-key-pair privateKey: algorithm: ECDSA size: 256 issuerRef: name: selfsigned-issuer kind: Issuer group: cert-manager.io - -- apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: server-ca-issuer spec: ca: secretName: server-ca-key-pair - -- apiVersion: v1 kind: Secret metadata: name: my-postgres-server-cert labels: cnpg.io/reload: "" - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: my-postgres-server-cert spec: secretName: my-postgres-server-cert usages: - server auth dnsNames: - cluster-example-lb.internal.mydomain.net - cluster-example-rw - cluster-example-rw.default - cluster-example-rw.default.svc - cluster-example-r - cluster-example-r.default - cluster-example-r.default.svc - cluster-example-ro - cluster-example-ro.default - cluster-example-ro.default.svc issuerRef: name: server-ca-issuer kind: Issuer group: cert-manager.io - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: client-ca spec: isCA: true commonName: my-selfsigned-client-ca secretName: client-ca-key-pair privateKey: algorithm: ECDSA size: 256 issuerRef: name: selfsigned-issuer kind: Issuer group: cert-manager.io - -- apiVersion: cert-manager.io/v1 kind: Issuer metadata: name: client-ca-issuer spec: ca: secretName: client-ca-key-pair - -- apiVersion: v1 kind: Secret metadata: name: my-postgres-client-cert labels: cnpg.io/reload: "" - -- apiVersion: cert-manager.io/v1 kind: Certificate metadata: name: my-postgres-client-cert spec: secretName: my-postgres-client-cert usages: - client auth commonName: streaming_replica issuerRef: name: client-ca-issuer kind: Issuer group: cert-manager.io - -- apiVersion: postgresql.cnpg.io/v1 kind: Cluster metadata: name: cluster-example spec: instances: 3 certificates: serverTLSSecret: my-postgres-server-cert serverCASecret: my-postgres-server-cert clientCASecret: my-postgres-client-cert replicationTLSSecret: my-postgres-client-cert storage: size: 1Gi deployment manifest.