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Following steps need to be performed before adding installing agent on LXC host to management server

• Fix cgroup co-mounting error in RHEL7: 
  • When cpu,cpuacct are co-mounted, libvirt fails to create containers. This issue is fixed in later versions of libvirt. For libvirt 1.1.1 which comes with RHEL7, below work-around is required
  • Rhel7 Initial RAM disk (initrd) uses systemd. Any changes made to cgroup will be lost after reboot.  So rebuild the initrd

  • Set JoinControllers to empty string in /etc/systemd/system.conf. Empty string ensures that systemd mounts all controllers in separate hierarchies

JoinControllers=

• • Backup initrd.

cp /boot/initramfs-$(uname -r).img /boot/initramfs-$(uname -r).img.bak

• • Rebuild initrd

dracut -f

• • Reboot host

• on RHEL7, NetworkManager resets mac address of the Vm: CLOUDSTACK-7515
• Disable NetworkManager  to work-around this issue:
  • service NetworkManager stop
  • chkconfig NetworkManager off
ToDo: cloudstack-setup-agent script should check if cgroup is properly mounted and raise exception if cgroups are not properly configured - CLOUDSTACK-7524

Versions

LXC version 1.0

Libvirt Version 1.21.1

Open Issues

LXC hosts need not be hvm enabled. So, a VM can also act as a host for LXC conatiners. Currently, cloudstack doesn't allow hosts which are not hvm enabled. This check has to be relaxed for LXC.

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