[ubuntu-cloud] UEC Single Point of failure

[Torsten Spindler]

On Thu, 2010-11-04 at 09:13 +0100, Björn Böttcher wrote:
...

> Still open question:
> But do the multiple CC/SC machines synchronize automatically?

Nope, the cluster controllers (CC) manage different clusters and do not
synchronize any state between them. Same for the storage controllers
(SC) that are attached to different clusters.

Instead your payload on UEC (e.g. a webapp) needs to be tailored for
fault tolerance, when a cluster fails. For example, a load balancer
outside of UEC may direct requests to either cluster in your UEC. If one
fails, the load balancer learns about it (maybe through a heartbeat?)
and directs any requests to the remaining cluster(s).

On your original question, the cloud controller (CLC) is indeed a single
point of failure. Putting it on hardware that provides some resilience
towards failures is best practice there.

Torsten