Comment # 1 on bug 971456 from Kristyna Streitova

The problem is on the first row of the %post section, where '%service_add_post'
macro is called:

<snip>
%post
%service_add_post mysql.service mysql@.service mysql.target
mysql@default.service
</snip>

Besides other things, '%service_add_post' macro runs 'systemctl preset' for all
these four services. mysql@default.service (it's a symlink to mysql@.service)
causes the problem.

I tried it separately and it seems that 'systemctl start' works fine, but
'enable' or 'preset' cause the "Too many levels of symbolic links" error
message.


$ ls -la /usr/lib/systemd/system/*mysql*
lrwxrwxrwx 1 root root  14 Feb 11 18:37 mysql@default.service -> mysql@.service
-rw-r--r-- 1 root root 488 Feb 11 18:37 mysql.service
-rw-r--r-- 1 root root 457 Feb 11 18:37 mysql@.service
-rw-r--r-- 1 root root  64 Feb 11 18:37 mysql.target

$ systemctl start mysql@default.service 

$ systemctl status mysql@default.service
��� mysql@default.service - MySQL server - default instance
   Loaded: loaded (/usr/lib/systemd/system/mysql@.service; disabled; vendor
preset: disabled)
   Active: active (running) since Fri 2016-04-01 15:55:37 CEST; 23s ago
  Process: 2570 ExecStartPost=/usr/lib/mysql/mysql-systemd-helper wait %i
(code=exited, status=0/SUCCESS)
  Process: 2558 ExecStartPre=/usr/lib/mysql/mysql-systemd-helper upgrade %i
(code=exited, status=0/SUCCESS)
  Process: 2466 ExecStartPre=/usr/lib/mysql/mysql-systemd-helper install %i
(code=exited, status=0/SUCCESS)
 Main PID: 2569 (mysqld)
    Tasks: 23 (limit: 512)
   CGroup: /system.slice/system-mysql.slice/mysql@default.service
           ������2569 /usr/sbin/mysqld --defaults-file=/etc/my.cnf --user=mysql

$ systemctl preset mysql@default.service
Failed to execute operation: Too many levels of symbolic links

$ systemctl enable mysql@default.service
Failed to execute operation: Too many levels of symbolic links

-----

@systemd maintainers: Could I ask if this is correct systemd behaviour? I
thought that since this commit [1] it's possible to enable/disable services via
symlinks in /usr. Thank you in advance for any hint.


[1]
https://github.com/systemd/systemd/commit/0ec0deaa30d0e68430f03fa6f32affa576481d18