Hi Sathwik, I will concern your approach. Thank you for your effort.
On 6 June 2015 at 18:43, Sathwik B P <sathwik...@gmail.com> wrote: > I have attached to the JIRA https://issues.apache.org/jira/browse/ODE-563 > > On Sat, Jun 6, 2015 at 5:55 PM, sudharma subasinghe <suba...@cse.mrt.ac.lk > > > wrote: > > > Hi Sathwik, > > > > I can't find the attached document. Please kind be enough to resend it. > > > > On 6 June 2015 at 15:42, Sathwik B P <sathwik...@gmail.com> wrote: > > > > > Refer this one as I have corrected the numbering of steps. > > > > > > On Sat, Jun 6, 2015 at 3:33 PM, Sathwik B P <sathwik...@gmail.com> > > wrote: > > > > > >> Hi Sudharma/Tammo, > > >> > > >> Kindly review attached document on my proposed approach. Let me know > if > > >> you have any concerns or doubts on it. > > >> > > >> regards, > > >> sathwik > > >> > > >> On Fri, Jun 5, 2015 at 6:56 PM, Sathwik B P <sathwik...@gmail.com> > > wrote: > > >> > > >>> find response inline > > >>> > > >>> On Wed, Jun 3, 2015 at 10:22 PM, sudharma subasinghe < > > >>> suba...@cse.mrt.ac.lk> wrote: > > >>> > > >>>> Hi, > > >>>> > > >>>> Sorry for the late reply. I was trying to achieve a proper solution. > > >>>> Following is my approach. > > >>>> > > >>>> 1) I elected master node for deploying purpose. So when a master > node > > >>>> goes > > >>>> down hazelcast will elect the next oldest node for master. > > >>>> > > >>> > > >>> Perfect > > >>> > > >>> > > >>>> 2) ODEServer can identify whether clustering is enabled or not by > > >>>> getting > > >>>> the property value in ode-axis2.properties file. So I introduced new > > >>>> property called "ode-axis2.hazelcast.clustering.enabled". If there > is > > no > > >>>> clustering enabled server will work as it is. If clustering is > > enabled, > > >>>> cluster will be initialized. > > >>>> > > >>> > > >>> Perfect > > >>> > > >>> > > >>>> 3) In manual deployment its responsibility is taken by the > > >>>> DeploymentPoller. So I give the deployment capability to master > node,s > > >>>> poller by setting "isDeploymentFromODEFileSystemAllowed()" to > true.So > > >>>> others will not be able to go into check() method in > DeploymentPoller. > > >>>> So > > >>>> deployment will be done by only the master node. > > >>>> > > >>> > > >>> Perfect > > >>> > > >>> > > >>>> > > >>>> 4) In DeploymentWebService, I had to consider few cases.If the > deploy > > >>>> request goes to the master node, it will deploy the process through > > web > > >>>> service.Others pollers will not go into check() method as they are > not > > >>>> masters. So master can continue without any involvement of others. > > >>>> > > >>>> > > >>> Perfect > > >>> > > >>> > > >>>> 5) If the deploy request goes to a slave node, it will do up to file > > >>>> creation in the file system.Slave will be stopped at that point. As > > only > > >>>> master poller is checking, master can continue from created files in > > the > > >>>> file system. > > >>>> > > >>> > > >>> DeploymentWebService provides synchronous operations. The status > of > > >>> the operation should be communicated to the calling client in the > same > > call. > > >>> DeploymentPoller is a backend thread that goes over each and > every > > >>> directory under the Deployment directory checking for any changes to > > >>> deploy.xml in existing processes and deploy newly added processes. > This > > >>> process is sequential and time consuming. As the process directories > > >>> grows, so does the time taken for execution of the thread. > > >>> > > >>> Since the request is on a slave node and the processing is done > on > > >>> master node, how do you check for the completion of the > > >>> deployment/undeployment of processes and respond back to the client > > since > > >>> the web service call is a synchronous operation. As DeploymentPoller > is > > >>> taking a lot of time in processing, your request will time out right. > > >>> > > >>> > > >>>> > > >>>> 6) But there was problem with _deploymentUnits in ProcessStoreImpl. > > Each > > >>>> _deploymentUnits stores only what its server has deployed. So think, > > >>>> that a > > >>>> master node goes down another master node appears.But its > > >>>> __deploymentUnits > > >>>> does not have dus which has deployed by the earlier master node. > Hence > > >>>> it > > >>>> will not be able retire earlier version of the process which is > > >>>> deployed by > > >>>> previous master. So there will two process which are in "ACTIVE" > state > > >>> > > >>> > > >>>> 7) To avoid this, I add the ODEServer as an Observer to check when a > > new > > >>>> master is electing, then load all the deployment units out of the > > >>>> store. So > > >>>> new master node can have all the dus and can retire appropriate > > version. > > >>>> Usually loadAll() is called at the server start-up time. But there > is > > no > > >>>> other way to solve this. I tried to use Hazelcast IMap to store all > > dus > > >>>> among all nodes. But it wasn't success as du is not serializable > > >>>> object. > > >>>> > > >>> > > >>>> 8) I figured out that we do not need send cluster message to others > as > > >>>> all > > >>>> the dus' data are persisted to the shared DB. So each node can take > > the > > >>>> du > > >>>> and retrieve necessary data using already implemented methods in > > Process > > >>>> Store. > > >>>> > > >>>> 9) But there is an another problem.The axis2 service corresponding > to > > a > > >>>> deployed process does not appear on all nodes of the cluster. That > is > > >>>> because each server add du which is deployed by it to the process > > >>>> store.That is why I had use loadAll() when masters are changing. How > > to > > >>>> solve this? > > >>>> > > >>> > > >>> I do appriciate your efforts in understanding the implmentation > and > > >>> changes that need to be done. You are bang on it. > > >>> fireEvent(..) is the method that triggers process activation and > > >>> necessary service creation. > > >>> > > >>> > > >>> But with this given apporach from steps 6 to 8, ODE cannot have > > >>> atleast 2 Active servers for Load balancing. You are concentrating on > > only > > >>> one active node that will do deployments and cater to process > > invocations. > > >>> We should also think about scaling ODE to multiple servers to > > handle > > >>> load. > > >>> > > >>> What do you think. > > >>> > > >>> > > >>>> Thank you, > > >>>> Sudharma > > >>>> > > >>>> On 2 June 2015 at 08:51, Sathwik B P <sathwik...@gmail.com> wrote: > > >>>> > > >>>> > Sudharma, > > >>>> > > > >>>> > Any updates? > > >>>> > > > >>>> > regards, > > >>>> > sathwik > > >>>> > > > >>>> > On Fri, May 29, 2015 at 5:26 PM, Sathwik B P < > sathwik...@gmail.com> > > >>>> wrote: > > >>>> > > > >>>> > > Sudharma, > > >>>> > > > > >>>> > > Can you elaborate on your option 1). > > >>>> > > > > >>>> > > Response to your option 2). > > >>>> > > > > >>>> > > Process Store is the component that handles process > metadata, > > >>>> > > compilation and deployment in ODE. Integration layers in ODE > > >>>> (Axis2, JBI) > > >>>> > > use the process store. > > >>>> > > Future implementations of IL for ODE will also use the > process > > >>>> store. > > >>>> > > We should not be thinking of moving the process store > > functionality > > >>>> to > > >>>> > the > > >>>> > > integration layers. > > >>>> > > > > >>>> > > > > >>>> > > On Thu, May 28, 2015 at 9:33 PM, sudharma subasinghe < > > >>>> > > suba...@cse.mrt.ac.lk> wrote: > > >>>> > > > > >>>> > >> Hi, > > >>>> > >> > > >>>> > >> I understood the problem within dynamic master/slave > > >>>> configuration. In > > >>>> > my > > >>>> > >> approach, when a deployment request is routed to a slave node > > >>>> there will > > >>>> > >> not be a deployment. I suggest two options to avoid it. > > >>>> > >> 1) Have static master/slave configuration only for deploy > process > > >>>> > >> > > >>>> > > 2) Modify the deployment web service to complie and verify the > > >>>> process > > >>>> > and > > >>>> > >> then copy it to the deploy folder irrespective of whether its a > > >>>> master > > >>>> > or > > >>>> > >> slave, then deployment poller should take care of the > deployment > > >>>> > >> > > >>>> > >> > > >>>> > > > > >>>> > >> > > >>>> > >> On 28 May 2015 at 14:43, Sathwik B P <sathwik...@gmail.com> > > wrote: > > >>>> > >> > > >>>> > >> > Sudharma, > > >>>> > >> > > > >>>> > >> > We definitely need a master/slave in the hazelcast cluster. > > This > > >>>> is > > >>>> > >> > probably needed for the job migration in the Scheduler to > > >>>> migrate the > > >>>> > >> jobs > > >>>> > >> > associated with a down node. Let hold on this topic for > future > > >>>> > >> discussion. > > >>>> > >> > > > >>>> > >> > Going by the explanation where the master/slave nodes have > > >>>> certain > > >>>> > >> > predefined tasks to perform is perfectly fine. > > >>>> > >> > > > >>>> > >> > I have this scenario, > > >>>> > >> > > > >>>> > >> > I am using HAProxy as my load balancer and configured 3 nodes > > in > > >>>> the > > >>>> > >> > cluster. > > >>>> > >> > > > >>>> > >> > Node1 - Active > > >>>> > >> > Node2 - Active > > >>>> > >> > Node3 - Backup > > >>>> > >> > > > >>>> > >> > Load balancing algorithm: RoundRobin > > >>>> > >> > > > >>>> > >> > A Backup node (Node3) is one which the load balancer will not > > >>>> route > > >>>> > >> > requests to, until one of the Active node i.e either Node1 or > > >>>> Node2 > > >>>> > has > > >>>> > >> > gone down. > > >>>> > >> > > > >>>> > >> > All these 3 nodes are also part of the hazelcast cluster as > > well. > > >>>> > >> > > > >>>> > >> > In the hazelcast cluster, assume Node1 is elected as the > > >>>> leader/master > > >>>> > >> and > > >>>> > >> > Node2,Node3 as slaves. > > >>>> > >> > > > >>>> > >> > I initiate the deploy operation on the DeploymentWebService > > >>>> which the > > >>>> > >> load > > >>>> > >> > balancer routes it to one of the Active nodes in the cluster, > > >>>> lets say > > >>>> > >> it's > > >>>> > >> > the Node1. Since Node1 is also the master in the hazelcast > > >>>> cluster, > > >>>> > >> > deployment is a success. > > >>>> > >> > > > >>>> > >> > I initiate another deploy operation on the > DeploymentWebService > > >>>> which > > >>>> > >> the > > >>>> > >> > load balancer routes it to the next active node which is > Node2. > > >>>> Since > > >>>> > >> Node2 > > >>>> > >> > is a slave in the Hazelcast cluster, What happens to the > > >>>> deployment? > > >>>> > >> > > > >>>> > >> > regards, > > >>>> > >> > sathwik > > >>>> > >> > > > >>>> > >> > On Wed, May 27, 2015 at 10:55 PM, sudharma subasinghe < > > >>>> > >> > suba...@cse.mrt.ac.lk > > >>>> > >> > > wrote: > > >>>> > >> > > > >>>> > >> > > Hi, > > >>>> > >> > > > > >>>> > >> > > I will explain my approach as much as possible. The oldest > > >>>> node in > > >>>> > the > > >>>> > >> > > hazelcast cluster is elected as the master node. In the > > >>>> failure of > > >>>> > the > > >>>> > >> > > master node, next oldest node will be elected as the master > > >>>> node. > > >>>> > This > > >>>> > >> > > master-slave configuration is just for deployment. When the > > >>>> > hazelcast > > >>>> > >> > > cluster elected the master node, that node becomes a master > > >>>> node for > > >>>> > >> > > deploying process. So it will do the deploying artifacts. > If > > >>>> you > > >>>> > want > > >>>> > >> to > > >>>> > >> > > get the idea of electing master node please refer the code > > >>>> which I > > >>>> > >> have > > >>>> > >> > > located in the github. ( > > >>>> > >> > > https://github.com/Subasinghe/ode/tree/ode_clustering) > > >>>> > >> > > > > >>>> > >> > > I identified separated actions which should be followed by > > the > > >>>> > master > > >>>> > >> and > > >>>> > >> > > salve nodes. > > >>>> > >> > > Actions which are followed by master node only > > >>>> > >> > > 1) create deployment unit > > >>>> > >> > > 2) set the version nu to deployment unit > > >>>> > >> > > 3) compile deployment unit > > >>>> > >> > > 4) scan deployment unit > > >>>> > >> > > 5) retire previous versions > > >>>> > >> > > Master node and slave nodes should create _processes which > > >>>> stores > > >>>> > >> > > ProcessConfImpl > > >>>> > >> > > Only master node will write the version nu to database, > > create > > >>>> > >> .deployed > > >>>> > >> > > file > > >>>> > >> > > > > >>>> > >> > > So there are some actions which should be followed only by > > >>>> master > > >>>> > node > > >>>> > >> > > while other actions should be followed by all the nodes.The > > >>>> idea of > > >>>> > >> > having > > >>>> > >> > > a master node is deploying artifacts and avoid others from > > >>>> writing > > >>>> > the > > >>>> > >> > > version nu to database. > > >>>> > >> > > Whether a node is active or passive, all nodes should do > the > > >>>> > >> > > deployment.Master > > >>>> > >> > > and slaves will follow necessary actions as in above. > > >>>> > >> > > > > >>>> > >> > > > > >>>> > >> > > > > >>>> > >> > > > > >>>> > >> > > > > >>>> > >> > > On 27 May 2015 at 15:49, Sathwik B P <sathwik...@gmail.com > > > > >>>> wrote: > > >>>> > >> > > > > >>>> > >> > > > Nandika, > > >>>> > >> > > > > > >>>> > >> > > > I very well understand what you have put across, but it's > > >>>> > secondary > > >>>> > >> to > > >>>> > >> > me > > >>>> > >> > > > now. > > >>>> > >> > > > > > >>>> > >> > > > Sudharma, > > >>>> > >> > > > My primary concern is to understand at a high level the > > >>>> deployment > > >>>> > >> > > > architecture and how would master-slave configuration fit > > >>>> in. Are > > >>>> > >> there > > >>>> > >> > > any > > >>>> > >> > > > restrictions imposed by the in-progress design? > > >>>> > >> > > > > > >>>> > >> > > > Firstly, how would ODE process deployment work under > these > > >>>> cluster > > >>>> > >> > > > configurations? > > >>>> > >> > > > > > >>>> > >> > > > Sample Cluster configurations: A load balancer is > > >>>> frontending the > > >>>> > >> > > servers. > > >>>> > >> > > > 1) Cluster consisting of 2 nodes all Active-Active. > > >>>> > >> > > > 2) Cluster consisting of 2 nodes Active-Passive. > > >>>> > >> > > > 3) Cluster with 2+ nodes with additional nodes either in > > >>>> Active or > > >>>> > >> > > Passive. > > >>>> > >> > > > > > >>>> > >> > > > regards, > > >>>> > >> > > > sathwik > > >>>> > >> > > > > > >>>> > >> > > > > > >>>> > >> > > > > > >>>> > >> > > > > > >>>> > >> > > > > > >>>> > >> > > > > > >>>> > >> > > > > > >>>> > >> > > > On Wed, May 27, 2015 at 3:04 PM, Nandika Jayawardana < > > >>>> > >> > jayaw...@gmail.com > > >>>> > >> > > > > > >>>> > >> > > > wrote: > > >>>> > >> > > > > > >>>> > >> > > > > 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 > > >>>> > >> > > > > > > > >> > > >>>> > >> > > > > > > > > > > >>>> > >> > > > > > > > > > > >>>> > >> > > > > > > > > > >>>> > >> > > > > > > > > >>>> > >> > > > > > > > >>>> > >> > > > > > > >>>> > >> > > > > > >>>> > >> > > > > >>>> > >> > > > >>>> > >> > > >>>> > > > > >>>> > > > > >>>> > > > >>>> > > >>> > > >>> > > >> > > > > > >
