Open Stack

On 04/15/2014 08:33 PM, Jay Pipes wrote:
> On Tue, 2014-04-15 at 12:01 +0100, Duncan Thomas wrote:
>> On 14 April 2014 19:51, James Penick <penick at yahoo-inc.com> wrote:
>>> We drive the ³VM=Cattle² message pretty hard. Part of onboarding a
>>> property to our cloud, and allowing them to serve traffic from VMs is
>>> explaining the transient nature of VMs. I broadcast the message that all
>>> compute resources die, and if your day/week/month is ruined because of a
>>> single compute instance going away, then you¹re doing something Very
>>> Wrong. :)
>>
>> While I agree with the message, if cloud provider A has VM restarts
>> every hour, and B has restarts every 6 months, all other things being
>> equal I'm going to go with B.
>
> Pretty sure James wasn't saying that he restarts VMs every hour. The
> idea is that applications that run on a utility cloud should be
> resilient and take into account failure as an expected part of
> operating.

This is certainly true for public utility clouds.  I'd expect any 
application on a public cloud to be cloud-aware.

On the other hand, there are companies that want to use OpenStack for 
private cloud management, and these may be running applications that are 
not cloud-aware. Thay may have been migrated to a private cloud for 
server consolidation, etc. and they're looking for some of the same 
enterprise-type functionality that they can get from vmware but with the 
advantages of free (both beer and speech) software.

>> Restarts are a pain point for most
>> systems, requiring data resynchronisation etc, so looking to minimise
>> them is a good aim as long as it doesn't conflict much with other
>> concerns...
>
> I'm actually not entirely sure what restarts and data resync have to do
> with vm-level HA? What am I missing here?

In some cases if you're doing hot-standby then you can take out the 
active and have the standby take over without needing to restart anything.

Chris