There is a difference between ps_tokudb_admin in 5.6 and 5.7. In 5.7 on CentOS 7 tokudb settings are put into /etc/sysconfig/mysql instead of my.cnf like 5.6. This is why TokuDB storage engine needs to be re-enabled after upgrade.
Possible solution would be for ps_tokudb_admin to add tokudb setting in /etc/sysconfig/mysql for 5.6 on CentOS 7 as well. This shouldn't have any issues for 5.6 as this file isn't being used by mysqld_safe, but should avoid additional steps of re-enabling the tokudb after 5.6 -> 5.7 upgrade on CentOS 7.
There is a difference between ps_tokudb_admin in 5.6 and 5.7. In 5.7 on CentOS 7 tokudb settings are put into /etc/sysconfig/ mysql instead of my.cnf like 5.6. This is why TokuDB storage engine needs to be re-enabled after upgrade.
Possible solution would be for ps_tokudb_admin to add tokudb setting in /etc/sysconfig/ mysql for 5.6 on CentOS 7 as well. This shouldn't have any issues for 5.6 as this file isn't being used by mysqld_safe, but should avoid additional steps of re-enabling the tokudb after 5.6 -> 5.7 upgrade on CentOS 7.