"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. >> >> > The current semantics are that this file produces a new random UUID each >> > time the host OS is booted. Obviously each time we start a container now, >> > they just see the host's random boot_id, so from a container's POV this >> > does not change each time it starts. >> >> That is correct. As I recall the contract with boot_id is to provide >> a unique per boot value to assist in dealing with boots etc. I seem >> to recall emacs uses the combination of hostname+boot_id to help >> generate unique lock files names. >> >> I would definitely need a refresher on how boot_id is used in practice >> by applications other than SystemD before I could suggest a good design. > > This post seems to describe what emacs wants boot_id for: > > http://marc.info/?l=linux-kernel&m=93613053109494&w=2 > > With this info, I think emacs inside a container would expect the boot_id > to change each time the container is started, so they can detect stale > locks from an emacs instance in a previous boot of the container. Thanks that patch does clarify the original purpose. Unfortunately the lines of communication were crossed because emacs 24.1 most certainly does not use /proc/sys/kernel/random/boot_id. Eric _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
