Hi, On Wed, Nov 26, 2014 at 1:16 PM, Imesh Gunaratne <[email protected]> wrote:
> Hi Devs, > > This is to discuss the clustering model of the cloud controller: > > > > > As shown in the above diagram the idea is to have a coordinator node to > handle data persistence logic and message publishing (topology, instance > status, etc). The coordinator will be selected randomly and at a given time > there will be only one coordinator. If the existing coordinator node goes > down, another member will become the coordinator automatically (similar to > carbon clustering agent). > We gonna enable Hazelcast clustering right? Then Hazelcast Carbon clustering agent provides an API to check whether a node is the coordinator. > According to this design Autoscaler (AS)/Stratos Manager (SM) will talk to > Cloud Controller (CC) via the Cloud Controller Service endpoint exposed via > the load balancer. > > *Data Replication* > When a request comes into one of the CC instances it will execute the > necessary actions and update the data holder and/or topology which is in > memory. At this point the data holder changes will be replicated to other > instances using a distributed map. Once the coordinator receives the above > updates it will persist the changes to the registry database. > Are we sending a notification (cluster message) when the distributed map updated? > > In this design we might not need to replicate the topology since it is > already there in the message broker. The idea is to let coordinator publish > the topology changes and the other members to listen to it. > This would add a latency for the events. What are the issues we would face, when each node sends out the event? Of course, the complete topology should only be sent out by the Coordinator. Also, we need to make CC data publishers activated only when a node is the Coordinator. Further, only the Coordinator should react to the Instance status events etc. IMO. There's a cache to hold the validated partitions of a Cartridge, we need to use a distributed hash map for that too. > > Please add your thoughts. > > Thanks > > > -- > Imesh Gunaratne > > Technical Lead, WSO2 > Committer & PMC Member, Apache Stratos > -- Best Regards, Nirmal Nirmal Fernando. PPMC Member & Committer of Apache Stratos, Senior Software Engineer, WSO2 Inc. Blog: http://nirmalfdo.blogspot.com/
