On Fri, Sep 21, 2012 at 09:22:24PM +1000, Amos Shapira wrote:
> 2. Maintenance - if I get to share the common disk image among all of them
> then I only need to install/update it once instead of once for each KVM
> guest (we already use Puppet but it doesn't mean it comes for free).
How do you plan on upgrading the read-only VMs after the initial
installation, or are they short-lived and frequently recreated from
scratch using a fresh image? Read-only, shared /usr between machines
is a nice idea in theory, but at least the modern linux distros'
package management tend not to support it that well in practice.
The KVM agents host Atlassian Bamboo build agents (
http://www.atlassian.com/software/bamboo/overview).
I want them to run continuously and be ready to be used for builds but:
1. I can take them down for maintenance any time between builds.
2. They are disposable (i.e. loosing them for disk crash is NOT a catastrophe), so I want maximum speed even on expense of less (or actually no) redundancy.
The only way to update their software that I could think of so far is to rebuild the base image on the KVM host and reboot the KVM guests from the new image next time they become idle.
Have you got other ideas?