<div dir="ltr">Dear Milan,<div><br></div><div>Thank you for your explanation. </div><div>Very clear!</div><div><br></div><div>Regards,</div><div>Terry</div></div><div class="gmail_extra"><br><div class="gmail_quote">2018-03-02 0:03 GMT+08:00 Milan Zamazal <span dir="ltr"><<a href="mailto:mzamazal@redhat.com" target="_blank">mzamazal@redhat.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="im HOEnZb">Terry hey <<a href="mailto:recreationh@gmail.com">recreationh@gmail.com</a>> writes:<br>
<br>
> Dear Milan,<br>
> Today, i just found that oVirt 4.2 support iLO5 and power management was<br>
> set on all hosts (hypervisor).<br>
> I found that if i choose VM lease and shutdown iSCSI network, the VM was<br>
> shutdown.<br>
> Then the VM will migrate to another host if the iSCSI network was resumed.<br>
<br>
</span><span class="im HOEnZb">If the VM had been shut down then it was probably restarted on rather<br>
than migrated to another host.<br>
<br>
</span><span class="im HOEnZb">> If i just choose enable HA on VM setting, the VM was successfully migrate<br>
> to another hosts.<br>
<br>
</span><span class="im HOEnZb">There can be a special situation if the storage storing VM leases is<br>
unavailable.<br>
<br>
oVirt tries to do what it can in case of storage problems, but it all<br>
depends on the overall state of the storage – for how long it remains<br>
unavailable, if it is available at least on some hosts, and which parts<br>
of the storage are available; there are more possible scenarios here.<br>
Indeed, it's a good idea to experiment with failures and learn what<br>
happens before real problems come!<br>
<br>
</span><span class="im HOEnZb">> But i want to ask another question, what if the management network is down?<br>
> What VM and hosts behavior would you expect?<br>
<br>
</span><span class="im HOEnZb">The primary problem is that oVirt Engine can't communicate with the<br>
hosts in such a case. Unless there is another problem (especially<br>
assuming storage is still reachable from the hosts) the hosts and VMs<br>
will keep running, but the hosts will be displayed as unreachable and<br>
VMs as unknown in Engine. And you won't be able to manage your VMs from<br>
Engine of course. Once the management network is back, things should<br>
return to normal state sooner or later.<br>
<br>
Regards,<br>
Milan<br>
<br>
</span><div class="HOEnZb"><div class="h5">> Regards<br>
> Terry Hung<br>
><br>
> 2018-02-28 22:29 GMT+08:00 Milan Zamazal <<a href="mailto:mzamazal@redhat.com">mzamazal@redhat.com</a>>:<br>
><br>
>> Terry hey <<a href="mailto:recreationh@gmail.com">recreationh@gmail.com</a>> writes:<br>
>><br>
>> > I am testing iSCSI bonding failover test on oVirt, but i observed that VM<br>
>> > were paused and did not migrate to another host. Please see the details<br>
>> as<br>
>> > follows.<br>
>> ><br>
>> > I have two hypervisors. Since they are running iLO 5 and oVirt 4.2 cannot<br>
>> > support iLO 5, thus i cannot setup power management.<br>
>> ><br>
>> > For the cluster setting, I set "Migrate Virtual Machines" under the<br>
>> > Migration Policy.<br>
>> ><br>
>> > For each hypervisor, I bonded two iSCSI interface as bond 1.<br>
>> ><br>
>> > I created one Virtual machine and enable high availability on it.<br>
>> > Also, I created one Virtual machine and did not enable high availability<br>
>> on<br>
>> > it.<br>
>> ><br>
>> > When i shutdown one of the iSCSI interface, nothing happened.<br>
>> > But when i shutdown both iSCSI interface, VM in that hosts were paused<br>
>> and<br>
>> > did not migrate to another hosts. Is this behavior normal or i miss<br>
>> > something?<br>
>><br>
>> A paused VM can't be migrated, since there are no guarantees about the<br>
>> storage state. As the VMs were paused under erroneous (rather than<br>
>> controlled such as putting the host into maintenance) situation,<br>
>> migration policy can't help here.<br>
>><br>
>> But highly available VMs can be restarted on another host automatically.<br>
>> Do you have VM lease enabled for the highly available VM in High<br>
>> Availability settings? With a lease, Engine should be able to restart<br>
>> the VM elsewhere after a while, without it Engine can't do that since<br>
>> there is danger of resuming the VM on the original host, resulting in<br>
>> multiple instances of the same VM running at the same time.<br>
>><br>
>> VMs without high availability must be restarted manually (unless storage<br>
>> domain becomes available again).<br>
>><br>
>> HTH,<br>
>> Milan<br>
>><br>
</div></div></blockquote></div><br></div>