[Encrypted InnoDB tablespace backups] keyring_file dependency should be documented

[Laurynas Biveinis]

[In:/doc/percona-xtrabackup/LATEST/advanced/encrypted_innodb_tablespace_backups.html]

Currenly, the doc page discusses taking backups of encrypted tablespaces without mentioning anything about server keyrings in use. That XB introduces keyring_file_data option, implies that it works only with keyring_file and not with any other keyring plugin. This should be documented.

[Sergei Glushchenko (sergei.glushchenko)]

Eventually, xtrabackup should support keyring plugins.

Another option is to fetch master keys from server itself using 'keyring_key_fetch' from recently introduced keyring_udf and re-encrypt tablespace keys with the backup master key provided at the time of backup.

As for current implementation, we should state that it only works with default keyring file plugin.

[Laurynas Biveinis (laurynas-biveinis)]

Does XB query the running server for the active keyring plugin currently?

[Sergei Glushchenko (sergei.glushchenko)]

It doesn't. When this support was added the only available plugin was keyring_file.

[Laurynas Biveinis (laurynas-biveinis)]

Perhaps adding such check sooner would help with better diagnostics once plugins proliferate and someone attempts using older XB versions to take backups on such servers

[Sergei Glushchenko (sergei.glushchenko)]

Agree. Reported as bug 1658612

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PXB-779