Tuesday, September 4, 2007

Services - XINETD and INIT

Services in Linux:
Services in linux are classified into TWO.
XINETD and INIT based services.
XINETD is itself an INIT based service.
All INIT based services are invoked by the command,
#/etc/init.d/service start
XINETD services' configuration file resides in /etc/xinetd.d directory.
All the services are made persistent across reboots by
#chkconfig servicename on , for all init based services.
#chkconfig xinetd on , for all xinetd based services.

XINETD services: e(X)tended (I)(N)tern(E)(T) services (D)aemon
xinetd service is called a super server as it serves as the daemon for a number of seperate services.
For all the services which use xinetd, we need to start the xinetd daemon only. xinetd services' configuration files can be found at /etc/xinetd.d/servicename
All the xinetd services are having the same syntax facilitating the administration of xinetd services very easy.
Extensive logging and fine grained access control can be implemented with xinetd
Xinetd service forks process ids only when a client requests the service.
Only one process is necessary to invoke process ids for individual xinetd services, ie the xinetd super daemon itself.
Logging based on hostname are not supported in XINETD

INIT based services:
INIT based services are having individual configuration files under
Their starting scripts are placed under /etc/init.d/servicename.
Each individual services can be started by
#/etc/init.d/servicename start

and to sum up... the more the processes .. the lesser the performance of the machine..
so it is advisable to have more xinetd based services than init based ones..!

No comments: