> On Wed, Mar 16 2016, Benjamin Coddington wrote: > > > On Wed, 16 Mar 2016, NeilBrown wrote: > > > >> On Sat, Mar 12 2016, Benjamin Coddington wrote: > >> > >> > The nfs-config service exists to translate distro-specific startup > >> > configuration into the command line arguments used by systemd to start nfs > >> > utilities. Unfortunately, it is not clear to most users that this service > >> > must be recycled every time startup configurations have been modified, as > >> > this requirement is a change for at least one distro. > >> > > >> > We can get rid of nfs-config by generating the startup arguments in an > >> > ExecStartPre option for each service that needs them. We'll also have to > >> > break out the EnvironmentFile into a separate file for each service to > >> > avoid races overwriting this file. > >> > > >> > A distro taking this change should also modify their > >> > /usr/lib/systemd/scripts/nfs-utils_env.sh script to include the new > >> > EnvironmentFile location for each service. > >> > > >> > Signed-off-by: Benjamin Coddington <bcodding@xxxxxxxxxx> > >> > >> I can't say I really like this, but it does make sense and solves a real > >> problem. > >> Maybe: I would never have written it myself, but I'm kind-a glad you did > >> :-) > > > > Which bits are unlikeable? I am guessing that all these little intermediate > > files are the issue; that is what I hate. I admit that it is a least-effort > > approach to fixing the problem. What does the ideal fix look like to you? > > I don't like having multiple intermediate config files that are all > identical, and I don't like having to run the config script every time > any daemon is (re)started. > > I'm not sure what "ideal" would be. > > One improvement would be if systemd could be given an executable in > place of an environment file with the implication that it would run the > executable and read environment variables from the stdout. > That would remove the multiple config files. > It would still mean the script is run every time, but I could be > convinced that isn't so bad. > > An alternate idea is that maybe systemd could have a directive so that > in any transaction were "this" unit is started, "that" unit will also be > started. Then we could replace "Wants=nfs-config.server" with > "Prepare=nfs-config.service" so if systemd ever needed to start any > nfs-related service, it would make preparations by first running > nfs-config.service - only once per transaction. > > But unless you want to hack on systemd, I think what you have is good > enough. > > > .... hmmm. I wonder what would happen if we just removed > "RemainAfterExit=y" from nfs-config.service. Would it cause things to > fail, or would it cause nfs-config.service to be run every time. > > Hey, that looks like it works! Can you double check for me? > i.e. revert your patch, remove "RemainAfterExit=y" from > nfs-config.service, and then see if nfs-config.service gets run any time > any nfs server is started. Yep.. that appears to work just fine. Seems like a simpler solution than this change. It appears to me ( from systemd.service(5) ) that systemd's state transitions for Type=Oneshot will avoid races that might overwrite the environment file. Nice find! Ben -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
