Thread: postmaster: init.d/start
Hi, under SuSe Linux 6.3 there are different subdirectories rc<X>.d for different runlevels. Each dir contains links to the start/stop scripts. The filenames contain numbers to indicate the position / the order of the services to start. Where (for which runlevel) and at what position should I link the pg start/stop script? Why should one link it for more than one runlevel (I noticed this for apache)? Thanks, Markus
This is the System V-style initialisation. The layout is as follows: /etc/rc.d/init.d/ This directory contains the actual scripts which start and stop the various services on the system. The system supplies a 'start' or 'stop' parameter for the call of the script depending on whether the system is starting up (or changing runlevel) or shutting down. /etc/rc.d/rcX.d As you say, these correspond to each of the runlevels. Each of these directories contains symbolic links to the scripts in ../init.d corresponding to the services to be started or stopped in that runlevel. Links to services to be started in that runlevel start with S and those to be stopped (killed) start with K. Then there is a number, so the system knows what order to start the services in (eg. networking needs to be brought up before name services can start). As to which runlevel you should start the postmaster in, well, you'll probably want to start it in the runlevel(s) corresponding to full multiuser mode, and multisuer mode with X (if applicable). On my RedHat system, these are runlevels 3 and 5. I think they're different on a SuSE system, 2 and 3 from memory. Check your /etc/inittab for details, it'll tell you which runlevel corresponds to what mode of use. So, to conclude: you need a script called (for example) postgresql int your /etc/rc.d/init.d directory. This will start and stop the postmaster, and should be written to expect 'start' or 'stop' as parameters. Take a look at (for example) the /etc/rc.d/init.d/apache startup script for a 'template' of how to do this. Obviously you'll need the commands to start/stop the postmaster rather than apache when building this script ;). Secondly, you'll have to decide which runlevels you want the postmaster to start in (probably 2 and 3, I may be wrong). Then create a link in the rcX.d directories corresponding to those runlevels up to the startup script for starting the postmaster, and shutting it down when the runlevel changes. For example: cd /etc/rc.d/init.d pico postgresql <write a script, test it works> cd ../rc3.d ln -s ../postgresql S60postgresql ln -s ../postgresql K60postgresql ... and so on for other runlevels. You might want to put a kill link in the runlevel directory used for system shutdown (6 on my system) so postmaster gets shut down properly. As far as at what point you should start the postmaster, you should start it after the services that it depends on have started, so probably after networking and maybe named, if you run it. I find that around 60-ish works well. Hope this helps, Dan On Sat, 10 Jun 2000, Markus Wagner wrote: > Hi, > > under SuSe Linux 6.3 there are different subdirectories rc<X>.d for > different runlevels. Each dir contains links to the start/stop scripts. > The filenames contain numbers to indicate the position / the order of > the services to start. > > Where (for which runlevel) and at what position should I link the pg > start/stop script? > Why should one link it for more than one runlevel (I noticed this for > apache)? > > Thanks, > > Markus > > Daniel Fairs danfairs@bits.bris.ac.uk, danfairs@hotmail.com http://www.darkalley.co.uk, http://listen.to/agentorange Just because you're not paranoid doesn't mean they're not out to get you.
Hi Daniel, thank you for your reply. There are some unanswered questions. Why does one have to consider multiple run levels? Doesn't run level 3 (network + X) implicate run level 2 (network)? So if I don't use XDM (or equivalent) and the system starts with a login shell only, it would start run level 2 services. And if I use XDM and the system starts using X it would also load run level 2 services? Markus Daniel Fairs wrote: > As to which runlevel you should start the postmaster in, well, you'll > probably want to start it in the runlevel(s) corresponding to full > multiuser mode, and multisuer mode with X (if applicable). On my RedHat > system, these are runlevels 3 and 5. I think they're different on a SuSE > system, 2 and 3 from memory. Check your /etc/inittab for details, it'll > tell you which runlevel corresponds to what mode of use. > it after the services that it depends on have started, so probably after > networking and maybe named, if you run it. I find that around 60-ish works
Markus Wagner wrote: > > Hi Daniel, > > thank you for your reply. > > There are some unanswered questions. > Why does one have to consider multiple run levels? Doesn't run level 3 > (network + X) implicate run level 2 (network)? > So if I don't use XDM (or equivalent) and the system starts with a login > shell only, it would start run level 2 services. And if I use XDM and > the system starts using X it would also load run level 2 services? Not neccesarily. each run-level contains it's own list of services. They may, or may not, overlap. BTW, Runlevel3 is generally networking + NFS, NOT X. X is usually runlevel 5 (all depending on the variant). if you start a system not configured to go to X-RUnlevel, it will usually go to runlevel 3 (Don't recall ever seeing a default system go to runlevel two; Unix/Linux).
>Hi Daniel, > >thank you for your reply. > >There are some unanswered questions. >Why does one have to consider multiple run levels? Doesn't run level 3 >(network + X) implicate run level 2 (network)? Not on SuSE Linux. On SOlaris for example, you will find in /etc/inittab an entry like: s2:23:wait:/sbin/rc2 with the meaning that /sbin/rc2 will be executed in runlevel 2 AND 3 as well. So all the scripts in rc2.d will be started in runlevel 3 as well (on Solaris). In SuSE you find: l2:2:wait:/sbin/init.d/rc 2 l3:3:wait:/sbin/init.d/rc 3 So each runlevel just starts its scripts only. >So if I don't use XDM (or equivalent) and the system starts with a login >shell only, it would start run level 2 services. And if I use XDM and >the system starts using X it would also load run level 2 services? > No, not on SuSE. But you can change your /etc/inittab, if you like to have this behaviour. Actually, you will find (almost?) all scripts from /sbin/init.d/rc2.d doubled in /sbin/init.d/rc3.d for the reason, that runlevel 3 does NOT start the scripts for runlevel 2. Thomas Mack TU Braunschweig, Abt. Informationssysteme