On 08/31/2012 04:13 AM, Eric W. Biederman wrote: > "Daniel P. Berrange" <berrange@xxxxxxxxxx> writes: > >> On Thu, Aug 30, 2012 at 03:15:17PM -0700, Eric W. Biederman wrote: >>> "Daniel P. Berrange" <berrange@xxxxxxxxxx> writes: >>> >>>> One of the features that SystemD folks have asked us to fix in LXC, is >>>> to make sure that /proc/sys/kernel/random/boot_id changes each time a >>>> container is started. >>> >>> There may be a good reason for this. Most of the time what I have seen >>> of kernel requests from the direction of SystemD is that while there may >>> be a real problem but usually their imagined solution is not a >>> particularly good solution. So a description of the problem is needed. >>> >>> Justifying something with just SystemD wants this is a good way to get >>> a nack. >> >> SystemD records log messages for all system services in their journal. >> They can show you all log messages for the current service execution, >> all log messages for a service since system boot, or all log messsages >> ever. The boot_id value is used as a unique tag to allow grouping of >> the log messages per system boot. When we run systemd inside a container >> we want to get that grouping of log messages generated by services inside >> the container, to take account of the container boot, not the host boot. >> Hence the desire to have the boot_id value reflect when a container is >> booted. > > Since SystemD post-dates containers and since the logging feature is not > currently in wide use that use case is completely non-persuasive. > > So far this just sounds like a plain SystemD bug and something that can > be easily changed at this point in time. > > It has been a long time but my fuzzy memory says that the originial > boot_id justification was based on use cases that could not be solved > any other way. > > My memory says it was this thread https://lkml.org/lkml/1999/5/31/233 > that inspired the implementation of boot_id. However reading the > current emacs source code it appears emacs gave up before boot_id > was implemented and stats /var/run/random-seed (which we seem to > have removed) or looks in wtmp or utmp for the latest boot record. > > I did a quick grep through the binaries on my system and I could not > find anything using /proc/sys/random/boot_id. > > That suggests to me that the proper solution is to actually just remove > boot_id. > > Hmm. And then there is other interesting detail. What should boot_id > return after the processes have migrated from one system to another. > Since this would be a per-boot id, this clearly has to be carried over with migration, along with all the tons of data we already carry. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
