Hi Lahiru, good summarization. Thanks Lahiru.
I think you are trying to stick to a model where Orchestrator distributing to work for GFac worker and trying to do the impedance mismatch through a messaging solution. If you step back and think, we don't even want the orchestrator to handle everything. From its point of view, it should submit jobs to the framework, and will wait or get notified once the job is done. There are multiple ways of doing this. And here is one method. Orchestrator submits all its jobs to Job queue (implemented using any MQ impl like Rabbit or Kafka). A storm topology is implemented to dequeue messages, process them (i.e. submit those jobs and get those executed) and notify the Orchestrator with the status (either through another JobCompletionQueue or direct invocation). With this approach, the MQ provider will help to match impedance between job submission and consumption. Storm helps with worker coordination, load balancing, throttling on your job execution framework, worker pool management and fault tolerance. Of course, you can implement this based only on ZK and handle everything else on your own but storm had done exactly that with the use of ZK underneath. Finally, if you go for a model like this, then even beyond job submission, you can use the same model to do anything within the framework for internal communication. For example, the workflow engine will submit its jobs to queues based on what it has to do. Storm topologies exists for each queues to dequeue messages and carry out the work in a reliable manner. Consider this as mini-workflows within a larger workflow framework. We can have a voice chat if its more convenient. But not at 7am PST :) Thanks, Eran Chinthaka Withana On Tue, Jun 17, 2014 at 10:12 AM, Lahiru Gunathilake <[email protected]> wrote: > Hi All, > > Ignoring the tool that we are going to use to implement fault tolerance I > have summarized the model we have decided so far. I will use the tool name > as X, we can use Zookeeper or some other implementation. Following design > assume tool X and Registry have high availability. > > 1. Orchestrator and GFAC worker node communication is going to be queue > based and tool X is going to be used for this communication. (We have to > implement this with considering race condition between different gfac > workers). > 2. We are having multiple instances of GFAC which are identical (In future > we can group gfac workers). Existence of each worker node is identified > using X. If node goes down orchestrator will be notified by X. > 3. When a particular request comes and accepted by one gfac worker that > information will be replicated in tool X and a place where this information > is persisted even the worker failed. > 4. When a job comes to a final state like failed or cancelled or completed > above information will be removed. So at a given time orchestrator can poll > active jobs in each worker by giving a worker ID. > 5. Tool X will make sure that when a worker goes down it will notify > orchestrator. During a worker failure, based on step 3 and 4 orchestrator > can poll all the active jobs of that worker and do the same thing like in > step 1 (store the experiment ID to the queue) and gfac worker will pick the > jobs. > > 6. When GFAC receive a job like in step 5 it have to carefully evaluate the > state from registry and decide what to be done (If the job is pending then > gfac just have to monitor, if job state is like input transferred not even > submitted gfac has to execute rest of the chain and submit the job to the > resource and start monitoring). > > If we can find a tool X which supports all these features and tool itself > is fault tolerance and support atomicity, high availability and simply API > to implement we can use that tool. > > WDYT ? > > Lahiru > > > On Mon, Jun 16, 2014 at 2:38 PM, Supun Kamburugamuva <[email protected]> > wrote: > > > Hi Lahiru, > > > > Before moving with an implementation it may be worth to consider some of > > the following aspects as well. > > > > 1. How to report the progress of an experiment as state in ZooKeeper? > What > > happens if a GFac instance crashes while executing an experiment? Are > there > > check-points we can save so that another GFac instance can take over? > > 2. What is the threading model of GFac instances? (I consider this as a > > very important aspect) > > 3. What are the information needed to be stored in the ZooKeeper? You may > > need to store other information about an experiment apart from its > > experiment ID. > > 4. How to report errors? > > 5. For GFac weather you need a threading model or worker process model? > > > > Thanks, > > Supun.. > > > > > > > > > > > > On Mon, Jun 16, 2014 at 2:22 PM, Lahiru Gunathilake <[email protected]> > > wrote: > > > > > Hi All, > > > > > > I think the conclusion is like this, > > > > > > 1, We make the gfac as a worker not a thrift service and we can start > > > multiple workers either with bunch of providers and handlers configured > > in > > > each worker or provider specific workers to handle the class path > issues > > > (not the common scenario). > > > > > > 2. Gfac workers can be configured to watch for a given path in > zookeeper, > > > and multiple workers can listen to the same path. Default path can be > > > /airavata/gfac or can configure paths like /airavata/gfac/gsissh > > > /airavata/gfac/bes. > > > > > > 3. Orchestrator can configure with a logic to store experiment IDs in > > > zookeeper with a path, and orchestrator can be configured to provider > > > specific path logic too. So when a new request come orchestrator store > > the > > > experimentID and these experiments IDs are stored in Zk as a queue. > > > > > > 4. Since gfac workers are watching they will be notified and as supun > > > suggested can use a leader selection algorithm[1] and one gfac worker > > will > > > take the leadership for each experiment. If there are gfac instances > for > > > each provider same logic will apply among those nodes with same > provider > > > type. > > > > > > [1]http://curator.apache.org/curator-recipes/leader-election.html > > > > > > I would like to implement this if there are no objections. > > > > > > Lahiru > > > > > > > > > On Mon, Jun 16, 2014 at 11:51 AM, Supun Kamburugamuva < > [email protected] > > > > > > wrote: > > > > > > > Hi Marlon, > > > > > > > > I think you are exactly correct. > > > > > > > > Supun.. > > > > > > > > > > > > On Mon, Jun 16, 2014 at 11:48 AM, Marlon Pierce <[email protected]> > > wrote: > > > > > > > > > Let me restate this, and please tell me if I'm wrong. > > > > > > > > > > Orchestrator decides (somehow) that a particular job requires > > JSDL/BES, > > > > so > > > > > it places the Experiment ID in Zookeeper's /airavata/gfac/jsdl-bes > > > node. > > > > > GFAC servers associated with this instance notice the update. The > > > first > > > > > GFAC to claim the job gets it, uses the Experiment ID to get the > > > detailed > > > > > information it needs from the Registry. ZooKeeper handles the > > locking, > > > > etc > > > > > to make sure that only one GFAC at a time is trying to handle an > > > > experiment. > > > > > > > > > > Marlon > > > > > > > > > > > > > > > On 6/16/14, 11:42 AM, Lahiru Gunathilake wrote: > > > > > > > > > >> Hi Supun, > > > > >> > > > > >> Thanks for the clarification. > > > > >> > > > > >> Regards > > > > >> Lahiru > > > > >> > > > > >> > > > > >> On Mon, Jun 16, 2014 at 11:38 AM, Supun Kamburugamuva < > > > > [email protected]> > > > > >> wrote: > > > > >> > > > > >> Hi Lahiru, > > > > >>> > > > > >>> My suggestion is that may be you don't need a Thrift service > > between > > > > >>> Orchestrator and the component executing the experiment. When a > new > > > > >>> experiment is submitted, orchestrator decides who can execute > this > > > job. > > > > >>> Then it put the information about this experiment execution in > > > > ZooKeeper. > > > > >>> The component which wants to executes the experiment is listening > > to > > > > this > > > > >>> ZooKeeper path and when it sees the experiment it will execute > it. > > So > > > > >>> that > > > > >>> the communication happens through an state change in ZooKeeper. > > This > > > > can > > > > >>> potentially simply your architecture. > > > > >>> > > > > >>> Thanks, > > > > >>> Supun. > > > > >>> > > > > >>> > > > > >>> On Mon, Jun 16, 2014 at 11:14 AM, Lahiru Gunathilake < > > > > [email protected]> > > > > >>> wrote: > > > > >>> > > > > >>> Hi Supun, > > > > >>>> > > > > >>>> So your suggestion is to create a znode for each thrift service > we > > > > have > > > > >>>> and > > > > >>>> when the request comes that node gets modified with input data > for > > > > that > > > > >>>> request and thrift service is having a watch for that node and > it > > > will > > > > >>>> be > > > > >>>> notified because of the watch and it can read the input from > > > zookeeper > > > > >>>> and > > > > >>>> invoke the operation? > > > > >>>> > > > > >>>> Lahiru > > > > >>>> > > > > >>>> > > > > >>>> On Thu, Jun 12, 2014 at 11:50 PM, Supun Kamburugamuva < > > > > >>>> [email protected]> > > > > >>>> wrote: > > > > >>>> > > > > >>>> Hi all, > > > > >>>>> > > > > >>>>> Here is what I think about Airavata and ZooKeeper. In Airavata > > > there > > > > >>>>> are > > > > >>>>> many components and these components must be stateless to > achieve > > > > >>>>> scalability and reliability.Also there must be a mechanism to > > > > >>>>> > > > > >>>> communicate > > > > >>>> > > > > >>>>> between the components. At the moment Airavata uses RPC calls > > based > > > > on > > > > >>>>> Thrift for the communication. > > > > >>>>> > > > > >>>>> ZooKeeper can be used both as a place to hold state and as a > > > > >>>>> > > > > >>>> communication > > > > >>>> > > > > >>>>> layer between the components. I'm involved with a project that > > has > > > > many > > > > >>>>> distributed components like AIravata. Right now we use Thrift > > > > services > > > > >>>>> > > > > >>>> to > > > > >>>> > > > > >>>>> communicate among the components. But we find it difficult to > use > > > RPC > > > > >>>>> > > > > >>>> calls > > > > >>>> > > > > >>>>> and achieve stateless behaviour and thinking of replacing > Thrift > > > > >>>>> > > > > >>>> services > > > > >>>> > > > > >>>>> with ZooKeeper based communication layer. So I think it is > better > > > to > > > > >>>>> explore the possibility of removing the Thrift services between > > the > > > > >>>>> components and use ZooKeeper as a communication mechanism > between > > > the > > > > >>>>> services. If you do this you will have to move the state to > > > ZooKeeper > > > > >>>>> > > > > >>>> and > > > > >>>> > > > > >>>>> will automatically achieve the stateless behaviour in the > > > components. > > > > >>>>> > > > > >>>>> Also I think trying to make ZooKeeper optional is a bad idea. > If > > we > > > > are > > > > >>>>> trying to integrate something fundamentally important to > > > architecture > > > > >>>>> as > > > > >>>>> how to store state, we shouldn't make it optional. > > > > >>>>> > > > > >>>>> Thanks, > > > > >>>>> Supun.. > > > > >>>>> > > > > >>>>> > > > > >>>>> On Thu, Jun 12, 2014 at 10:57 PM, Shameera Rathnayaka < > > > > >>>>> [email protected]> wrote: > > > > >>>>> > > > > >>>>> Hi Lahiru, > > > > >>>>>> > > > > >>>>>> As i understood, not only reliability , you are trying to > > achieve > > > > >>>>>> some > > > > >>>>>> other requirement by introducing zookeeper, like health > > monitoring > > > > of > > > > >>>>>> > > > > >>>>> the > > > > >>>> > > > > >>>>> services, categorization with service implementation etc ... . > In > > > > that > > > > >>>>>> case, i think we can get use of zookeeper's features but if we > > > only > > > > >>>>>> > > > > >>>>> focus > > > > >>>> > > > > >>>>> on reliability, i have little bit of concern, why can't we use > > > > >>>>>> > > > > >>>>> clustering + > > > > >>>> > > > > >>>>> LB ? > > > > >>>>>> > > > > >>>>>> Yes it is better we add Zookeeper as a prerequisite if user > need > > > to > > > > >>>>>> use > > > > >>>>>> it. > > > > >>>>>> > > > > >>>>>> Thanks, > > > > >>>>>> Shameera. > > > > >>>>>> > > > > >>>>>> > > > > >>>>>> On Thu, Jun 12, 2014 at 5:19 AM, Lahiru Gunathilake < > > > > >>>>>> [email protected] > > > > >>>>>> wrote: > > > > >>>>>> > > > > >>>>>> Hi Gagan, > > > > >>>>>>> > > > > >>>>>>> I need to start another discussion about it, but I had an > > offline > > > > >>>>>>> discussion with Suresh about auto-scaling. I will start > another > > > > >>>>>>> thread > > > > >>>>>>> about this topic too. > > > > >>>>>>> > > > > >>>>>>> Regards > > > > >>>>>>> Lahiru > > > > >>>>>>> > > > > >>>>>>> > > > > >>>>>>> On Wed, Jun 11, 2014 at 4:10 PM, Gagan Juneja < > > > > >>>>>>> > > > > >>>>>> [email protected] > > > > >>>> > > > > >>>>> wrote: > > > > >>>>>>> > > > > >>>>>>> Thanks Lahiru for pointing to nice library, added to my > > > dictionary > > > > >>>>>>>> > > > > >>>>>>> :). > > > > >>>> > > > > >>>>> I would like to know how are we planning to start multiple > > > servers. > > > > >>>>>>>> 1. Spawning new servers based on load? Some times we call it > > as > > > > auto > > > > >>>>>>>> scalable. > > > > >>>>>>>> 2. To make some specific number of nodes available such as > we > > > > want 2 > > > > >>>>>>>> servers to be available at any time so if one goes down > then I > > > > need > > > > >>>>>>>> > > > > >>>>>>> to > > > > >>>> > > > > >>>>> spawn one new to make available servers count 2. > > > > >>>>>>>> 3. Initially start all the servers. > > > > >>>>>>>> > > > > >>>>>>>> In scenario 1 and 2 zookeeper does make sense but I don't > > > believe > > > > >>>>>>>> > > > > >>>>>>> existing > > > > >>>>>>> > > > > >>>>>>>> architecture support this? > > > > >>>>>>>> > > > > >>>>>>>> Regards, > > > > >>>>>>>> Gagan > > > > >>>>>>>> On 12-Jun-2014 1:19 am, "Lahiru Gunathilake" < > > [email protected] > > > > > > > > >>>>>>>> > > > > >>>>>>> wrote: > > > > >>>>>>> > > > > >>>>>>>> Hi Gagan, > > > > >>>>>>>>> > > > > >>>>>>>>> Thanks for your response. Please see my inline comments. > > > > >>>>>>>>> > > > > >>>>>>>>> > > > > >>>>>>>>> On Wed, Jun 11, 2014 at 3:37 PM, Gagan Juneja < > > > > >>>>>>>>> > > > > >>>>>>>> [email protected]> > > > > >>>>>>> > > > > >>>>>>>> wrote: > > > > >>>>>>>>> > > > > >>>>>>>>> Hi Lahiru, > > > > >>>>>>>>>> Just my 2 cents. > > > > >>>>>>>>>> > > > > >>>>>>>>>> I am big fan of zookeeper but also against adding multiple > > > hops > > > > in > > > > >>>>>>>>>> > > > > >>>>>>>>> the > > > > >>>>>>> > > > > >>>>>>>> system which can add unnecessary complexity. Here I am not > > able > > > to > > > > >>>>>>>>>> understand the requirement of zookeeper may be I am wrong > > > > because > > > > >>>>>>>>>> > > > > >>>>>>>>> of > > > > >>>> > > > > >>>>> less > > > > >>>>>>> > > > > >>>>>>>> knowledge of the airavata system in whole. So I would like > to > > > > >>>>>>>>>> > > > > >>>>>>>>> discuss > > > > >>>> > > > > >>>>> following point. > > > > >>>>>>>>>> > > > > >>>>>>>>>> 1. How it will help us in making system more reliable. > > > Zookeeper > > > > >>>>>>>>>> > > > > >>>>>>>>> is > > > > >>>> > > > > >>>>> not > > > > >>>>>>> > > > > >>>>>>>> able to restart services. At max it can tell whether service > > is > > > up > > > > >>>>>>>>>> > > > > >>>>>>>>> or not > > > > >>>>>>> > > > > >>>>>>>> which could only be the case if airavata service goes down > > > > >>>>>>>>>> > > > > >>>>>>>>> gracefully and > > > > >>>>>>> > > > > >>>>>>>> we have any automated way to restart it. If this is just > > matter > > > of > > > > >>>>>>>>>> > > > > >>>>>>>>> routing > > > > >>>>>>> > > > > >>>>>>>> client requests to the available thrift servers then this > can > > be > > > > >>>>>>>>>> > > > > >>>>>>>>> achieved > > > > >>>>>>> > > > > >>>>>>>> with the help of load balancer which I guess is already > there > > in > > > > >>>>>>>>>> > > > > >>>>>>>>> thrift > > > > >>>>>>> > > > > >>>>>>>> wish list. > > > > >>>>>>>>>> > > > > >>>>>>>>>> We have multiple thrift services and currently we start > > only > > > > one > > > > >>>>>>>>> > > > > >>>>>>>> instance > > > > >>>>>>> > > > > >>>>>>>> of them and each thrift service is a stateless service. To > > keep > > > > the > > > > >>>>>>>>> > > > > >>>>>>>> high > > > > >>>>>>> > > > > >>>>>>>> availability we have to start multiple instances of them in > > > > >>>>>>>>> > > > > >>>>>>>> production > > > > >>>> > > > > >>>>> scenario. So for clients to get an available thrift service we > > can > > > > >>>>>>>>> > > > > >>>>>>>> use > > > > >>>> > > > > >>>>> zookeeper znodes to represent each available service. There > are > > > > >>>>>>>>> > > > > >>>>>>>> some > > > > >>>> > > > > >>>>> libraries which is doing similar[1] and I think we can use > them > > > > >>>>>>>>> > > > > >>>>>>>> directly. > > > > >>>>>>> > > > > >>>>>>>> 2. As far as registering of different providers is concerned > > do > > > > >>>>>>>>>> > > > > >>>>>>>>> you > > > > >>>> > > > > >>>>> think for that we really need external store. > > > > >>>>>>>>>> > > > > >>>>>>>>>> Yes I think so, because its light weight and reliable and > > we > > > > have > > > > >>>>>>>>> > > > > >>>>>>>> to > > > > >>>> > > > > >>>>> do > > > > >>>>>>> > > > > >>>>>>>> very minimal amount of work to achieve all these features to > > > > >>>>>>>>> > > > > >>>>>>>> Airavata > > > > >>>> > > > > >>>>> because zookeeper handle all the complexity. > > > > >>>>>>>>> > > > > >>>>>>>>> I have seen people using zookeeper more for state > management > > > in > > > > >>>>>>>>>> distributed environments. > > > > >>>>>>>>>> > > > > >>>>>>>>>> +1, we might not be the most effective users of zookeeper > > > > because > > > > >>>>>>>>> > > > > >>>>>>>> all > > > > >>>> > > > > >>>>> of > > > > >>>>>>> > > > > >>>>>>>> our services are stateless services, but my point is to > > achieve > > > > >>>>>>>>> fault-tolerance we can use zookeeper and with minimal work. > > > > >>>>>>>>> > > > > >>>>>>>>> I would like to understand more how can we leverage > > > zookeeper > > > > in > > > > >>>>>>>>>> airavata to make system reliable. > > > > >>>>>>>>>> > > > > >>>>>>>>>> > > > > >>>>>>>>>> [1]https://github.com/eirslett/thrift-zookeeper > > > > >>>>>>>>> > > > > >>>>>>>>> > > > > >>>>>>>>> > > > > >>>>>>>>> Regards, > > > > >>>>>>>>>> Gagan > > > > >>>>>>>>>> On 12-Jun-2014 12:33 am, "Marlon Pierce" <[email protected] > > > > > > wrote: > > > > >>>>>>>>>> > > > > >>>>>>>>>> Thanks for the summary, Lahiru. I'm cc'ing the > Architecture > > > > list > > > > >>>>>>>>>>> > > > > >>>>>>>>>> for > > > > >>>> > > > > >>>>> additional comments. > > > > >>>>>>>>>>> > > > > >>>>>>>>>>> Marlon > > > > >>>>>>>>>>> > > > > >>>>>>>>>>> On 6/11/14 2:27 PM, Lahiru Gunathilake wrote: > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> Hi All, > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> I did little research about Apache Zookeeper[1] and how > to > > > use > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> it > > > > >>>> > > > > >>>>> in > > > > >>>>>>> > > > > >>>>>>>> airavata. Its really a nice way to achieve fault tolerance > > and > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> reliable > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> communication between our thrift services and clients. > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> Zookeeper > > > > >>>> > > > > >>>>> is a > > > > >>>>>>> > > > > >>>>>>>> distributed, fault tolerant system to do a reliable > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> communication > > > > >>>> > > > > >>>>> between > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> distributed applications. This is like an in-memory file > > > > system > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> which > > > > >>>>>>> > > > > >>>>>>>> has > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> nodes in a tree structure and each node can have small > > > amount > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> of > > > > >>>> > > > > >>>>> data > > > > >>>>>>> > > > > >>>>>>>> associated with it and these nodes are called znodes. > Clients > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> can > > > > >>>> > > > > >>>>> connect > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> to a zookeeper server and add/delete and update these > > > znodes. > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> In Apache Airavata we start multiple thrift services > > and > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> these > > > > >>>> > > > > >>>>> can > > > > >>>>>>> > > > > >>>>>>>> go > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> down for maintenance or these can crash, if we use > > zookeeper > > > > to > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> store > > > > >>>>>>> > > > > >>>>>>>> these > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> configuration(thrift service configurations) we can > > achieve > > > a > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> very > > > > >>>> > > > > >>>>> reliable > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> system. Basically thrift clients can dynamically > discover > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> available > > > > >>>>>>> > > > > >>>>>>>> service > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> by using ephemeral znodes(Here we do not have to change > > the > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> generated > > > > >>>>>>> > > > > >>>>>>>> thrift client code but we have to change the locations we > are > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> invoking > > > > >>>>>>> > > > > >>>>>>>> them). ephemeral znodes will be removed when the thrift > > service > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> goes > > > > >>>>>>> > > > > >>>>>>>> down > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> and zookeeper guarantee the atomicity between these > > > > operations. > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> With > > > > >>>>>>> > > > > >>>>>>>> this > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> approach we can have a node hierarchy for multiple of > > > > airavata, > > > > >>>>>>>>>>>> orchestrator,appcatalog and gfac thrift services. > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> For specifically for gfac we can have different types of > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> services > > > > >>>> > > > > >>>>> for > > > > >>>>>>> > > > > >>>>>>>> each > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> provider implementation. This can be achieved by using > the > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> hierarchical > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> support in zookeeper and providing some logic in > > gfac-thrift > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> service > > > > >>>>>>> > > > > >>>>>>>> to > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> register it to a defined path. Using the same logic > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> orchestrator > > > > >>>> > > > > >>>>> can > > > > >>>>>>> > > > > >>>>>>>> discover the provider specific gfac thrift service and > route > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> the > > > > >>>> > > > > >>>>> message to > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> the correct thrift service. > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> With this approach I think we simply have write some > > client > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> code > > > > >>>> > > > > >>>>> in > > > > >>>>>>> > > > > >>>>>>>> thrift > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> services and clients and zookeeper server installation > can > > > be > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> done as > > > > >>>>>>> > > > > >>>>>>>> a > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> separate process and it will be easier to keep the > > Zookeeper > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> server > > > > >>>>>>> > > > > >>>>>>>> separate from Airavata because installation of Zookeeper > > server > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> little > > > > >>>>>>> > > > > >>>>>>>> complex in production scenario. I think we have to make > sure > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> everything > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> works fine when there is no Zookeeper running, ex: > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> enable.zookeeper=false > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> should works fine and users doesn't have to download and > > > start > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> zookeeper. > > > > >>>>>>>>>>> > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> [1]http://zookeeper.apache.org/ > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>>> Thanks > > > > >>>>>>>>>>>> Lahiru > > > > >>>>>>>>>>>> > > > > >>>>>>>>>>> > > > > >>>>>>>>>>> > > > > >>>>>>>>> -- > > > > >>>>>>>>> System Analyst Programmer > > > > >>>>>>>>> PTI Lab > > > > >>>>>>>>> Indiana University > > > > >>>>>>>>> > > > > >>>>>>>>> > > > > >>>>>>> -- > > > > >>>>>>> System Analyst Programmer > > > > >>>>>>> PTI Lab > > > > >>>>>>> Indiana University > > > > >>>>>>> > > > > >>>>>>> > > > > >>>>>> > > > > >>>>>> -- > > > > >>>>>> Best Regards, > > > > >>>>>> Shameera Rathnayaka. > > > > >>>>>> > > > > >>>>>> email: shameera AT apache.org , shameerainfo AT gmail.com > > > > >>>>>> Blog : http://shameerarathnayaka.blogspot.com/ > > > > >>>>>> > > > > >>>>>> > > > > >>>>> > > > > >>>>> -- > > > > >>>>> Supun Kamburugamuva > > > > >>>>> Member, Apache Software Foundation; http://www.apache.org > > > > >>>>> E-mail: [email protected]; Mobile: +1 812 369 6762 > > > > >>>>> Blog: http://supunk.blogspot.com > > > > >>>>> > > > > >>>>> > > > > >>>>> > > > > >>>> -- > > > > >>>> System Analyst Programmer > > > > >>>> PTI Lab > > > > >>>> Indiana University > > > > >>>> > > > > >>>> > > > > >>> > > > > >>> -- > > > > >>> Supun Kamburugamuva > > > > >>> Member, Apache Software Foundation; http://www.apache.org > > > > >>> E-mail: [email protected]; Mobile: +1 812 369 6762 > > > > >>> Blog: http://supunk.blogspot.com > > > > >>> > > > > >>> > > > > >>> > > > > >> > > > > > > > > > > > > > > > > > -- > > > > Supun Kamburugamuva > > > > Member, Apache Software Foundation; http://www.apache.org > > > > E-mail: [email protected]; Mobile: +1 812 369 6762 > > > > Blog: http://supunk.blogspot.com > > > > > > > > > > > > > > > > -- > > > System Analyst Programmer > > > PTI Lab > > > Indiana University > > > > > > > > > > > -- > > Supun Kamburugamuva > > Member, Apache Software Foundation; http://www.apache.org > > E-mail: [email protected]; Mobile: +1 812 369 6762 > > Blog: http://supunk.blogspot.com > > > > > > -- > System Analyst Programmer > PTI Lab > Indiana University >
