gpfdists:// Protocol

gpfdists:// Protocol

The gpfdists:// protocol is a secure version of the gpfdist:// protocol. To use it, you run the gpfdist utility with the --ssl option. When specified in a URI, the gpfdists:// protocol enables encrypted communication and secure identification of the file server and the Greenplum Database to protect against attacks such as eavesdropping and man-in-the-middle attacks.

gpfdists implements SSL security in a client/server scheme with the following attributes and limitations:
  • Client certificates are required.
  • Multilingual certificates are not supported.
  • A Certificate Revocation List (CRL) is not supported.
  • The TLSv1 protocol is used with the TLS_RSA_WITH_AES_128_CBC_SHA encryption algorithm.
  • SSL parameters cannot be changed.
  • SSL renegotiation is supported.
  • The SSL ignore host mismatch parameter is set to false.
  • Private keys containing a passphrase are not supported for the gpfdist file server (server.key) and for the Greenplum Database (client.key).
  • Issuing certificates that are appropriate for the operating system in use is the user's responsibility. Generally, converting certificates as shown in https://www.sslshopper.com/ssl-converter.html is supported.
    Note: A server started with the gpfdist --ssl option can only communicate with the gpfdists protocol. A server that was started with gpfdist without the --ssl option can only communicate with the gpfdist protocol.
  • The client certificate file, client.crt
  • The client private key file, client.key
Use one of the following methods to invoke the gpfdists protocol.
  • Run gpfdist with the --ssl option and then use the gpfdists protocol in the LOCATION clause of a CREATE EXTERNAL TABLE statement.
  • Use a gpload YAML control file with the SSL option set to true. Running gpload starts the gpfdist server with the --ssl option, then uses the gpfdists protocol.

Using gpfdists requires that the following client certificates reside in the $PGDATA/gpfdists directory on each segment.

  • The client certificate file, client.crt
  • The client private key file, client.key
  • The trusted certificate authorities, root.crt

For an example of loading data into an external table security, see Example 3—Multiple gpfdists instances.