severity 827171 wishlist thankyou I was tempted to close this bug and say well uptime is the system uptime (or how "old" procfs thinks the system is) and that be it. I'll leave it open but as a wishlist. I suspect it may wait for some more kernel parameters to come but who knows.
On Mon, Jun 13, 2016 at 12:46:41PM +0200, Adam Borowski wrote: > > when using 'uptime' in containers (regardless what kind of containers), > > it shows the uptime of the host system rather than the one of the container. > > It _does_ work on vserver but not on lxc (and similar). Yes because there are real virtual machines and, uh, other things. The english language really fails about these sorts of things "real virtual". > 'uptime' is just a pretty-printer for /proc/uptime, you'd need to teach the > kernel what a "container" means. And here's a problem: unlike vserver where > containers are an in-kernel thing, lxc is merely a wrapper for This is the problem in a nutshell. For a "real" server you look at /proc/uptime and use that. For something like kvm the /proc/uptime is just like a real machine, so no issue. > I think the best approximation is the PID namespace -- ie, defining > containers as "having separate inits". But when did the current init start? > There _is_ task->real_start_time, ie, field 22 of /proc/1/stat, but it > changes whenever init is exec()ed. What we'd want is the time when unshare > was called, and I don't think that's stored anywhere. There is also the issue around start time of processes and how this interacts with /proc/uptime and its replacement. You will get processes that start before the computer was turned on and other oddities. I'm in two minds if you want uptime the program to do this. I think there needs to be something to do it but should it be uptime or perhaps a different binary or flag. So a few things: What is considered a "container" which triggers the alterative repsonse? Adam had the idea a different init but would that be confusing? I build a container one way get one answer, build it another its a different answer. How would uptime "know" its in a container? This is tied to the first question as there may be different container types and we only want to change for some. Once uptime knows its a container it wants to change to, how does it calculate the alternative uptime? Daniel had a suggested approach but does it work for all circumstances? - Craig -- Craig Small (@smallsees) http://dropbear.xyz/ csmall at : enc.com.au Debian GNU/Linux http://www.debian.org/ csmall at : debian.org GPG fingerprint: 5D2F B320 B825 D939 04D2 0519 3938 F96B DF50 FEA5
