Quoting Marian Marinov (m...@1h.com): > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 05/29/2014 01:06 PM, Eric W. Biederman wrote: > > Marian Marinov <m...@1h.com> writes: > > > >> Hello, > >> > >> I have the following proposition. > >> > >> Number of currently running processes is accounted at the root user > >> namespace. The problem I'm facing is that > >> multiple containers in different user namespaces share the process > >> counters. > > > > That is deliberate. > > And I understand that very well ;) > > > > >> So if containerX runs 100 with UID 99, containerY should have NPROC limit > >> of above 100 in order to execute any > >> processes with ist own UID 99. > >> > >> I know that some of you will tell me that I should not provision all of my > >> containers with the same UID/GID maps, > >> but this brings another problem. > >> > >> We are provisioning the containers from a template. The template has a lot > >> of files 500k and more. And chowning > >> these causes a lot of I/O and also slows down provisioning considerably. > >> > >> The other problem is that when we migrate one container from one host > >> machine to another the IDs may be already > >> in use on the new machine and we need to chown all the files again. > > > > You should have the same uid allocations for all machines in your fleet as > > much as possible. That has been true > > ever since NFS was invented and is not new here. You can avoid the cost of > > chowning if you untar your files inside > > of your user namespace. You can have different maps per machine if you are > > crazy enough to do that. You can even > > have shared uids that you use to share files between containers as long as > > none of those files is setuid. And map > > those shared files to some kind of nobody user in your user namespace. > > We are not using NFS. We are using a shared block storage that offers us > snapshots. So provisioning new containers is > extremely cheep and fast. Comparing that with untar is comparing a race car > with Smart. Yes it can be done and no, I > do not believe we should go backwards. > > We do not share filesystems between containers, we offer them block devices.
Yes, this is a real nuisance for openstack style deployments. One nice solution to this imo would be a very thin stackable filesystem which does uid shifting, or, better yet, a non-stackable way of shifting uids at mount. _______________________________________________ lxc-devel mailing list lxc-devel@lists.linuxcontainers.org http://lists.linuxcontainers.org/listinfo/lxc-devel
