[Bug 471615] [NEW] Linux containers not working on EC2

[Matei Zaharia]

Public bug reported:

Binary package hint: lxc

Linux containers fail to start on Karmic EC2 instances. Here's how to
reproduce the problem:

- Start up an instance of ami-5b1af932 (the current 32-bit EC2 AMI from http://uec-images.ubuntu.com/karmic/current/)
- Log in
- sudo apt-get update
- sudo apt-get install lxc
- Attempt to mount the cgroup file system (required for LXC), create a container, and run an application in it using the series of commands below:

ubuntu at domU-12-31-39-0A-D5-F6:~$ sudo mkdir /cgroup
ubuntu at domU-12-31-39-0A-D5-F6:~$ sudo mount -t cgroup cgroup /cgroup
ubuntu at domU-12-31-39-0A-D5-F6:~$ sudo lxc-create -n foo
ubuntu at domU-12-31-39-0A-D5-F6:~$ sudo lxc-execute -n foo /bin/echo hello

On the EC2 instances, the last command prints the following error:

lxc-execute: failed to clone(0x2c020000): Invalid argument
lxc-execute: Invalid argument - failed to fork into a new namespace
lxc-execute: failed to spawn '/usr/lib/lxc/lxc-init'

On a raw hardware install of Karmic server, the commands work fine and
the lxc-execute prints "hello".

I think this may be due to kernel config differences. In particular,
lxc-checkconfig shows a lot of things as disabled on EC2:

ubuntu at domU-12-31-39-0A-D5-F6:~$ lxc-checkconfig 
Kernel config /proc/config.gz not found, looking in other places...
Found kernel config file /boot/config-2.6.31-302-ec2
--- Namespaces ---
Namespaces: enabled
Utsname namespace: enabled
Ipc namespace: enabled
Pid namespace: disabled
User namespace: disabled
Network namespace: disabled
Multiple /dev/pts instances: disabled

--- Control groups ---
Cgroup: enabled
Cgroup namespace: enabled
Cgroup device: disabled
Cgroup sched: enabled
Cgroup cpu account: enabled
Cgroup memory controller: enabled
Cgroup cpuset: enabled

--- Misc ---
Veth pair device: enabled
Macvlan: enabled
File capabilities: enabled

In contrast, on my raw hardware install, only "user namespace" and
"cgroup device" are disabled.

** Affects: lxc (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: ec2 linux lxc

-- 
Linux containers not working on EC2
https://bugs.launchpad.net/bugs/471615
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