On Sun, May 26, 2013 at 10:29:25PM +0200, Helmut Grohne wrote: > I find it depressing to see four init/rc systems, of which three are > mutually incompatible in every single possible aspect. At the risk of adding another level of indirection, we could add a meta-init format that can generate an appropriate file for any of these. > Dependency annotation: > * sysv: LSB headers > * openrc: a shell function > * systemd: ini-file / not needed due to socket activation > * upstart: another syntax This should be fairly easy to generate from a meta-init format. > Socket activation: > * sysv: inetd can pass one accepting socket as stdin > * openrc: no clue > * systemd: sockets passed as fd 3 and higher + environment variables > LISTEN_FDS and LISTEN_PID > * upstart: socket passed as fd specified in environment variable > UPSTART_FDS If the services support socket activation, a sysvinit script could probably pass the FDs using an environment variable and some shell redirection. Alternately a small C wrapper could be used, or this could be pushed into start-stop-daemon. > Daemon startup signalling: > * sysv: shell script flexibility^Whell > * openrc: no clue, guess like sysv > * systemd: signalling via dbus, systemd-specific notification mechanism > or just assume it to be ready > * upstart: tracking via ptrace, tell number of expected forks ahead This would be harder to abstract. > Resource limits: > * sysv: shell has ulimit > * openrc: I guess like sysv > * systemd: declarative, ini-file > * upstart: declarative syntax We can generate ulimit commands for sysv and openrc and appropriate entries in the systemd and upstart files. > How is anyone supposed to write a service that runs with all of them? > > Disabling service: > * sysv: /etc/default/$service is frowned upon, update-rc.d $service > disable (or chkconfig if you are on redhat) > * openrc: rc-update something > * systemd: "three levels of off", systemctl disable $service.service, > but this gets more complex with lsb init script compatibility > * upstart: echo manual > /etc/init/$service.override We already have update-rc.d, so we can make it DTRT depending on the actual init system in use. > Given the above I do not believe supporting even two of the above in a > native way (i.e. without lsb compatibility) is possible for a > distribution like Debian. Is there any chance in pushing upstreams to > consolidate interfaces in any way to make this easier? A meta-init format would make everyone equally happy (or miserable, depending on your point of view), which may be the best way to solve the problem. I fear that consolidation of interfaces is unlikely to occur. -- brian m. carlson / brian with sandals: Houston, Texas, US +1 832 623 2791 | http://www.crustytoothpaste.net/~bmc | My opinion only OpenPGP: RSA v4 4096b: 88AC E9B2 9196 305B A994 7552 F1BA 225C 0223 B187
Attachment:
signature.asc
Description: Digital signature