Bug 810877 - VMs started on more than one host
Summary: VMs started on more than one host
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: rgmanager
Version: 6.3
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Ryan McCabe
QA Contact: Cluster QE
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-04-09 14:01 UTC by Lon Hohberger
Modified: 2012-04-09 14:43 UTC (History)
2 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2012-04-09 14:19:21 UTC
Target Upstream Version:


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Red Hat Knowledge Base (Solution) 96543 0 None None None Never

Comment 2 Lon Hohberger 2012-04-09 14:01:59 UTC
Description of problem:

* If the libvirt-guests initscript is enabled while rgmanager is managing the
-same- virtual machines, the initscript, being not cluster-aware, will start
VMs already under rgmanager control on other hosts in the cluster.

* If the guests are configured to autostart using 'virsh autostart', the
libvirt tools will automatically start the virtual machines already under
rgmanager control on other hosts in the cluster.

These situations can end up with data loss in the virtual machines.

When running the cluster software to manage virtual machines, it is very
important to adhere to the following:

1) The libvirt-guests init script must be disabled.

2) All guests configured for cluster control must be disabled from an
auto-start perspective (e.g. virsh autostart --disable myvm1).

3) It is a best practice to use a non-default path for storing virtual machine
configuration files.  For example, use /mnt/guests (the default is
/etc/libvirt/qemu).  NOTE: If this is correctly done, steps (1) and (2) may not
be necessary.

4) Cluster-managed virtual machines must be managed using the cluster software.
 Do not mix usage of virt-manager, virsh, or other tools with rgmanager / luci.


The combination of these provide the following benefits:

a) Deterministic virtual machine behavior

b) Prevention of accidental management by other, non-cluster tools.


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