Some configuration flags are marked 'unsafe' and 'experimental'. Such flags are disabled by default. You can access these flags by enabling the additional flags, --unlock_unsafe_flags and --unlock_experimental_flags.
Note that these flags might be removed or modified without a deprecation period or any prior notice in future Kudu releases. Cloudera does not support using unsafe and experimental flags. As a rule of thumb, Cloudera will not support any configuration flags not explicitly documented in the Kudu Configuration Reference Guide.