<div dir="ltr"><div><div>Hi,<br><br></div>On 4.0 A new RFE is introduced that allows to define a VmPool as stateful (up until now it was stateless by default) - <a href="https://bugzilla.redhat.com/show_bug.cgi?id=1234394">https://bugzilla.redhat.com/show_bug.cgi?id=1234394</a> .<br></div><div>A stateful vm pool means that no stateless snapshot will be created when a vm is allocated from the pool, and so vm's disk persist after a user is done using the vm.<br></div>Current implementation is such that this is configurable both on creation of the pool and later is editable allowing to change a pool from stateless to stateful and vice versa.<div><div><div>More explanations and possible problems are discussed in the bz above.<br><br>I would like to raise a question regarding the behaviour of the pool when<br>
changing the pool from stateless to stateful and from stateful to stateless.<br>
<br>
1.<br>
Statless to stateful -> In this case, if all vms are down while the change<br>
occurs then we have no problem at all.<br>
If we have some vms up and allocated to some user - we expect that snapshot<br>
persists and is removed only once the vms are down. Then they go back to the<br>
previous state. And from that point vm is stateful.<br>
If we have prestared vms it's basically the same and we can expect admin to<br>
shutdown the vms in order for the snapshot to be removed.<br>
So this flow might be messy and cause confusion but not that problematic.<br>
<br>
2.<br>
Stateful to stateless -> This one is more problematic.<br>
In this case the question raised is, once we changed the pool to stateless,<br>
does that mean that the vm's initial state is the state that was left when<br>
using it as stateful? Or do we re create the vm according to the pool's<br>
template just like we do when changing a pool's template or template version? <br>This might cause loss of data which is what the user that requested this RFE wanted to avoid.<br>
<br>
In my personal opinion whether a pool is stateful or stateless sohuld be<br>
determined upon creation and not be changeable, but if that's not the case, we<br>
have to decide on the wanted behaviour for question 2.<br><br></div><div>Please share your thoughts on the issue.<br><br></div><div>Thanks.<br></div><div><br><br>-- <br><div class="gmail_signature"><div dir="ltr"><div><div><div><b>Sefi Litmanovich</b><br></div>RHEV-M QE<br></div>Compute Team<br></div></div></div>
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