Hi Sathwik, According to my understanding, in the clustering scenario, the master node should perform all the deployment actions and the slave nodes also need to perform some deployment actions. For example, the slave nodes also should handle the process ACTIVATED event so that the process configuration is added to the engine and necessary web services are created so that when the load balancer send requests to any node in the cluster, it is ready to accept those requests.
Regards Nandika On Wed, May 27, 2015 at 12:30 PM, Sathwik B P <sathwik...@gmail.com> wrote: > Sudharma, > > Where are you going to configure the master-slaves, is it in the web > application level or at the load balancer? > > regards, > sathwik > > On Tue, May 26, 2015 at 7:42 PM, sudharma subasinghe < > suba...@cse.mrt.ac.lk> > wrote: > > > Hi Tammo, > > > > Can you suggest the best method from these to implement? As first I > > suggested the master-slaves scenario I think it is easy to implement than > > distributed lock scenario. However if you can suggest one from these two, > > then I can think about it. > > > > Thank you > > > > On 21 May 2015 at 12:40, Sathwik B P <sathwik...@gmail.com> wrote: > > > > > With respect to the hotdeployment, > > > > > > We can drop the deployment archive onto the deployment folder. Since > the > > > DeploymentPoller are acquiring the distributed lock for the > > DeploymentUnit, > > > only one of the nodes will get the lock and initiate the deployment. > > > DeploymentPollers on other nodes will fail in acquiring the lock and > > hence > > > will silently ignore it. > > > > > > On Thu, May 21, 2015 at 12:30 PM, Sathwik B P <sathwik...@gmail.com> > > > wrote: > > > > > > > Hi Tammo, > > > > > > > > The distributed lock acquisition on the DeploymentUnit should be > added > > to > > > > both DeploymentWebService and DeploymentPoller. > > > > > > > > When a deployment operation is initiated through the > > > DeploymentWebService, > > > > The load balancer routes it to any of the available nodes. > > > > > > > > On the routed node, the DeploymentWebService acquires the Distributed > > > > lock. On the remaining nodes the DeploymentPoller will try to acquire > > the > > > > distributed lock and will not get it and hence will silently ignore > it. > > > > > > > > Once the routed node completes the deployment, it will release the > > lock. > > > > This way we don't have to stall the DeploymentPoller in other nodes. > > > > > > > > Does it answer the concerns? > > > > > > > > > > > > Now, if we give the responsibility of identifying the master node to > > the > > > > hazelcast, how do we plan to intimate the load balancer to change > it's > > > > configuration about the master node? > > > > Assuming there are 3 nodes in the cluster, > > > > node1 -master > > > > node2 - slave > > > > node3 - slave > > > > > > > > Node1 goes down, the LB will promote Node2 as master node, but > > hazelcast > > > > might promote Node3 as master node. They are out of sync. > > > > > > > > Is this argument valid? > > > > > > > > regards, > > > > sathwik > > > > > > > > On Wed, May 20, 2015 at 1:51 PM, Tammo van Lessen < > > tvanles...@gmail.com> > > > > wrote: > > > > > > > >> Hi Sudharma, > > > >> > > > >> what do you expect from the "other nodes deployment"? Compilation is > > not > > > >> needed since the CBP file is written to the (shared) FS. > Registration > > is > > > >> also not needed, since it is done via the shared database. So the > only > > > >> thing that might be needed is to tell the engine that there is a new > > > >> deployment. I'd need to check that. If this is needed, I revert my > > last > > > >> statement, then it is perhaps better to just send an event over > > > Hazelcast > > > >> to all nodes that the deployment has changed. > > > >> > > > >> Best, > > > >> Tammo > > > >> > > > >> On Wed, May 20, 2015 at 10:13 AM, sudharma subasinghe < > > > >> suba...@cse.mrt.ac.lk > > > >> > wrote: > > > >> > > > >> > Hi Tammo, > > > >> > > > > >> > The master node writes meta data. But runtime information must be > > > >> available > > > >> > in all nodes.Since the folder is shared, all nodes will see the > > > >> > availability of a new process. My idea is for master node to write > > the > > > >> meta > > > >> > data and other nodes to just read the meta data and load > process.So > > we > > > >> need > > > >> > a small delay between master node deployment and other nodes > > > deployment. > > > >> > > > > >> > Is there anyway to set the delay between master node and slaves > > until > > > >> > master node finish the deployment? > > > >> > > > > >> > Thank you > > > >> > Sudharma > > > >> > > > > >> > > > > >> > On 20 May 2015 at 13:01, Tammo van Lessen <tvanles...@gmail.com> > > > wrote: > > > >> > > > > >> > > Hi Sathwik, > > > >> > > > > > >> > > On Wed, May 20, 2015 at 6:40 AM, Sathwik B P < > > sathwik...@gmail.com> > > > >> > wrote: > > > >> > > > > > >> > > > Sudharma/Tammo, > > > >> > > > > > > >> > > > 1) How do we plan to decide which is the master node in the > > > cluster? > > > >> > > > > > > >> > > > > > >> > > I think the easiest approach is to always elect the oldest node > in > > > the > > > >> > > cluster to be the master. AFAIK Hazelcast can easily asked for > > this > > > >> > > information. > > > >> > > > > > >> > > > > > >> > > > > > >> > > > 2) Don't we need to stall the Deployment Pollers in the slave > > > nodes? > > > >> > > > > > > >> > > > > > > >> > > Absolutely. > > > >> > > > > > >> > > Suggestion: > > > >> > > > I am not sure whether do we need Master-SLaves. Why not give > > every > > > >> node > > > >> > > in > > > >> > > > the cluster the same status (Active-Active). > > > >> > > > > > > >> > > > When a new deployment is made, the load balancer can push it > to > > > any > > > >> of > > > >> > > the > > > >> > > > available nodes. That node will probably acquire a distributed > > > lock > > > >> on > > > >> > > the > > > >> > > > deployment unit and acts as master for that deployment. This > > > ensures > > > >> > > > optimum usage of the cluster nodes. Probably no static > > > >> configuration of > > > >> > > > Master-Slave in the load balancer nor in the hazelcast. > > > >> > > > > > > >> > > > > > >> > > But this would not allow to have the hotdeployment via > filesystem > > > >> still > > > >> > > enabled, right? > > > >> > > > > > >> > > Best, > > > >> > > Tammo > > > >> > > > > > >> > > > > > >> > > -- > > > >> > > Tammo van Lessen - http://www.taval.de > > > >> > > > > > >> > > > > >> > > > >> > > > >> > > > >> -- > > > >> Tammo van Lessen - http://www.taval.de > > > >> > > > > > > > > > > > > > >
