If you use a commercial certificate, ensure that you follow these steps.

  1. Ensure that the certificate originates from a trusted source.
  2. Verify that the certificate includes a Site certificate, a CA certificate, and a Trust Root certificate.
  3. If these certificates are available as separate files, merge them to make a single file. Run the following command:
    #cat [site cert] [CA cert] [Trust Root(if there’s one)] > chaincert.crt
  4. Copy the merged file to the following folder:
    /etc/docker/certs.d/<replace-with-custom-FQDN>:<port>