On 16 April 2014 03:33, Jay Pipes <[email protected]> wrote: >> 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.
A certain amount of reduxio absurdium involved in my post, but the point stands. >> 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? Not so much to do with VM level H/A as the general danger of the cattle .v. pets argument taken too far. I've been in summit sessions before where people have seriously argued that we shouldn't bother with rolling upgrade or live migration of VMs because people should expect their VMs to die at any time, and shutting down all of the VMs on a cloud for an upgrade is a totally reasonable thing to do. While I agree that unexpected VM death should be something you expect occasionally, I am also aware that this approach has a cost for the customer, in terms of complexity, reliability and performance, and a good cloud provider should look at what steps can reasonably be taken to avoid VMs dying, where practical, else another cloud provider who does take such steps will end up with more business. -- Duncan Thomas _______________________________________________ OpenStack-dev mailing list [email protected] http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-dev
