Again, you solved my problems  :-)

That did the job. I have been struggling with this problem over the weekend, without any path to this. I understand that this is a Linux-related "issue", and not at all directly related to LXD. I'll remember that!

On another idea... do you have any plan to support IPVLAN directly in LXD? For our use case (we're deploying LXC containers inside Openstack instances), the only viable way without too much hassle on the entworking side is to use IPVLAN but, right now, this requests to have pre-populated IPVLAN network devices outside of the LXD environment.

---
Christian Tardif

-------------------------

On 2016-11-08 00:11, Stéphane Graber wrote:
On Tue, Nov 08, 2016 at 03:00:48AM +0000, Christian Tardif wrote:
Hi,

I just faced a strange issue with LXD containers. I'm using them quite
extensively, but never faced that before. Normally, the userID that are presented to the container (they're coming from SSSD with ActiveDirectory
backend) are relatively low...   2000, 3000, that kind of ID's

Last friday, at the office, I built two containers (Ubuntu 16.04, CentOS 7.1) with the same kind of configuration regarding authentication; SSSD. And I notice that I wasn't able to log in via SSH. But one of my colleague was able to. We re-checke the config, just to make sure (but at the same time, it was impossible for this config to fail, as it is presented to the servers via Puppet. So the same config, and on the same OS level as other installs (we have numerous Ubuntu 16.04 with the same config, but the first one on
LXD containers).

We were trying to find out what piece was missing when we discover that this is not just the logging that fails, but everything related to these high UserID's. They are coming from a calculation based on Windows SID's for the user, which gives a huge range of userID's, from a few thousands to tens, if not hundreds thousands. So with my user, I can't set a permission with it, and I can't login.In fact, I don't exist with this user other than using
"getent passwd", or "id".

What can be the cause? Something to do with namespaces, maybe? cgroups?

We'ew in the dark. And until we can solve this, LXD containers aren't that
helpful to us, unfortunately.
--------------------------------------------------------------------------------
Christian Tardif

Hey there,

By default LXD uses a range of 65536 uid and gid as the user namespace
map for the containers.

This means that only uid 0 through 65536 exist in your container,
anything outside of that will be treated as invalid by the kernel.


sssd and similar authentication mechanisms will typically use uids/gids
above that POSIX range and so require you to grow the default map size
in /etc/subuid and /etc/subgid.


On the systems I use with sssd I typically just bump the allocation for
lxd and root in /etc/subuid and /etc/subgid from 65536 to 1000000 which
takes care of that problem.


_______________________________________________
lxc-users mailing list
[email protected]
http://lists.linuxcontainers.org/listinfo/lxc-users
_______________________________________________
lxc-users mailing list
[email protected]
http://lists.linuxcontainers.org/listinfo/lxc-users

Reply via email to