How to enable TLS encryption

This guide will show how to enable TLS using the self-signed-certificates operator as an example.

Summary

• Enable TLS
• Disable TLS
• Manage certificates
  • Check certificates in use
  • Update keys

Enable TLS

First, deploy the TLS charm:

juju deploy self-signed-certificates

To enable TLS on postgresql, integrate the two applications:

juju integrate self-signed-certificates postgresql

Disable TLS

You can disable TLS by removing the integration.

juju remove-relation self-signed-certificates postgresql

Manage certificates

Check certificates in use

To check the certificates in use by PostgreSQL, you can run:

openssl s_client -starttls postgres -connect <leader_unit_IP>:<port> | grep issuer

Update keys

Updates to private keys for certificate signing requests (CSR) can be made via the set-tls-private-key action. Note that passing keys to external/internal keys should only be done with base64 -w0, not cat.

With three replicas, this schema should be followed:

Generate a shared internal key:

openssl genrsa -out internal-key.pem 3072

Generate external keys for each unit:

openssl genrsa -out external-key-0.pem 3072
openssl genrsa -out external-key-1.pem 3072
openssl genrsa -out external-key-2.pem 3072

Apply both private keys to each unit. The shared internal key will be applied only to the juju leader.

juju run postgresql/0 set-tls-private-key "external-key=$(base64 -w0 external-key-0.pem)"  "internal-key=$(base64 -w0 internal-key.pem)"  --wait
juju run postgresql/1 set-tls-private-key "external-key=$(base64 -w0 external-key-1.pem)"  "internal-key=$(base64 -w0 internal-key.pem)"  --wait
juju run postgresql/2 set-tls-private-key "external-key=$(base64 -w0 external-key-2.pem)"  "internal-key=$(base64 -w0 internal-key.pem)"  --wait

Updates can also be done with auto-generated keys:

juju run postgresql/0 set-tls-private-key
juju run postgresql/1 set-tls-private-key
juju run postgresql/2 set-tls-private-key