The default connection string for Timescale uses the SSL mode require. If you want your connection client to verify the server's identity, you can connect with an SSL mode of verify-ca or verify-full. To do so, you need to store a copy of the certificate chain where your connection tool can find it.

This section provides instructions for setting up a stricter SSL connection.

All connections to Timescale are encrypted. As part of the secure connection protocol, the server proves its identity by providing clients with a certificate. This certificate should be issued and signed by a well-known and trusted Certificate Authority.

Because requesting a certificate from a Certificate Authority takes some time, Timescale databases are initialized with a self-signed certificate. This lets you start up a database immediately. After your service is started, a signed certificate is requested behind the scenes. The new certificate is usually received within 30 minutes. Your database certificate is then replaced with almost no interruption. Connections are reset, and most clients reconnect automatically.

With the signed certificate, you can switch your connections to a stricter SSL mode, such as verify-ca or verify-full.

For more information on the different SSL modes, see the PostgreSQL SSL mode descriptions.

To set up a stricter SSL connection:

  1. Generate a copy of your certificate chain and store it in the right location
  2. Change your Timescale connection string
  1. Use the openssl tool to connect to your Timescale service and get the certificate bundle. Store the bundle in a file called bundle.crt.

    Replace $SERVICE_URL_WITH_PORT with your Timescale connection URL:

    openssl s_client -showcerts -partial_chain -starttls postgres \
    -connect $SERVICE_URL_WITH_PORT < /dev/null 2>/dev/null | \
    awk '/BEGIN CERTIFICATE/,/END CERTIFICATE/{ print }' > bundle.crt
  2. Copy the bundle to your clipboard:

    pbcopy < bundle.crt
  3. Navigate to This online tool generates a full certificate chain, including the root CA certificate, which is not included in the certificate bundle returned by the database.

  4. Paste your certificate bundle in the provided box. Check Include Root Certificate. Click Generate Chain.

  5. Save the downloaded certificate chain to ~/.postgresql/root.crt.

  6. Change your Timescale connection string from sslmode=require to either sslmode=verify-full or sslmode=verify-ca. For example, to connect to your database with psql, run:

    psql "postgres://tsdbadmin@$SERVICE_URL_WITH_PORT/tsdb?sslmode=verify-full"

To check whether the certificate has been replaced yet, connect to your database instance and inspect the returned certificate:

openssl s_client -showcerts -partial_chain -starttls postgres -connect <HOST>:<PORT> < /dev/null 2>/dev/null | grep "ZeroSSL"


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