Because you talk about legacy code?

Posted Nov 25, 2011 13:26 UTC (Fri) by anselm (subscriber, #2796)
In reply to: Because you talk about legacy code? by khim
Parent article: That newfangled Journal thing

Yes, but which SysV init are you talking about the traditional one where you get to set all the symbolic links yourself, or the one most distributions are using these days, where the symbolic links are set automatically from dependencies in the LSB headers of the init scripts?

In the former case, any ordering you can explicitly impose on SysV init scripts through numbers in symbolic links can trivially be replicated through explicit »Before=« and »After=« dependencies in systemd. This most emphatically does not require a deeper understanding of the problem than you would need to come up with a suitable ordering for SysV init in the first place.

In the latter case, you need to specify all the dependencies in the LSB script headers for the benefit of your SysV init, and the LSB script header doesn't let you do anything that systemd dependencies don't let you do too. If anything, the systemd dependencies are a lot more expressive than the LSB script-header ones, so your job should be that much easier.

Finally, if you need to wait for something to »stabilise« after you have started a service in systemd, you can write a shell wrapper around that service which does the check, and that shell wrapper will be vastly simpler than a full SysV init script.