HDDS-8514. Improve ozone admin cert list subcommand count limits

[Galsza]

What changes were proposed in this pull request?

Add a warning to the user when the list subcommand lists too few certificates that they should increase the batch size.

What is the link to the Apache JIRA

HDDS-8514

How was this patch tested?

Github actions show no test failures and tried out the command on a local cluster.

[ashishkumar50]

@Galsza , Thanks for working on this, Please find few comments.

[fapifta]

Via the current protocol design it is not possible to get the overall count of the certs, we should consider to extend the protocol response with the number of certs in the RocksDB column family, as it would be still useful to show the users the actual number of certs.

In order to do so, you can add an optional field in the SCMListCertificateResponseProto defined in SCMServerSecurityProtocol.proto, then change the implementation of the listCertificates, and return the overal count not just the list of fetched certs, so you can use that in line 94 as CertCount value, and you can give a more precise message at the end.
The current final log message is fine (after adding batch size to the message) for the case when the value is not present in the response (new client queries old server).

The non-plus-ultra would be to provide the command that produces the next batch using the -s and -c as the last line of the output.

[Galsza]

As discussed in DM, the method for the number of certs in the RocksDB column family has 2 problems: it's only giving back an estimated count and for OM certs it will cause problems. It's not worth trying to use it this way.

[fapifta]

Yes, we agreed that it might cause more trouble than it solves. Thank you for updating the patch.

+1, pending CI.

[ChenSammi]

Thanks @Galsza improving the message, and @fapifta for the code review.