Agree with Vova, partial deployment does not make much sense in deployAll method. Partial deployment can be performed with a deploy method in a loop.
On Wed, Sep 6, 2017 at 6:21 PM, Vladimir Ozerov <voze...@gridgain.com> wrote: > Well, if we cannot rollback services easily then *why* we have a mode where > we declare a kind of false "atomicity"? > > On Wed, Sep 6, 2017 at 6:21 PM, Vladimir Ozerov <voze...@gridgain.com> > wrote: > > > Well, if we cannot rollback services easily then when we have a mode > where > > we declare a kind of false "atomicity"? > > > > On Wed, Sep 6, 2017 at 6:17 PM, Dmitriy Setrakyan <dsetrak...@apache.org > > > > wrote: > > > >> On Wed, Sep 6, 2017 at 8:10 AM, Vladimir Ozerov <voze...@gridgain.com> > >> wrote: > >> > >> > Dima, > >> > > >> > No, my point is to remove method with flag and never allow partial > >> > deployment. I do not needsee any practical use cases for this. > >> > > >> > >> The problem is not in practical use cases, but also in our ability to > >> rollback the already started services. I think it is much easier for us > to > >> support the partial deployment than try to implement complex rollback > >> procedures. Also, from a user standpoint, it can be easily explained and > >> seems to be a potentially useful feature. I would keep the partial > >> deployment. > >> > >> > >> > > >> > On Wed, Sep 6, 2017 at 6:06 PM, Dmitriy Setrakyan < > >> dsetrak...@apache.org> > >> > wrote: > >> > > >> > > Vova, makes sense. Couple of comments. > >> > > > >> > > > >> > > 1. allowPartialUpdate -> allowPartialDeploy > >> > > 2. I do not think we need the 2nd deployAll method. This is not > the > >> > API > >> > > where we need convenience shortcuts. > >> > > 3. Partial deployment is a failure, not success, so the exception > >> > should > >> > > be thrown. However, we must make sure that this exception has > list > >> of > >> > > services that failed to deploy with proper error messages, if > >> > possible. > >> > > > >> > > D. > >> > > > >> > > On Wed, Sep 6, 2017 at 8:01 AM, Vladimir Ozerov < > voze...@gridgain.com > >> > > >> > > wrote: > >> > > > >> > > > Igniters, > >> > > > > >> > > > Personally, I do not like the flag name - hard to understand and > >> use. > >> > > What > >> > > > if instead we define the following API: > >> > > > > >> > > > void deployAll(Collection<ServiceConfiguration> cfgs, boolean > >> > > > allowPartialUpdate) throws ServiceDeploymentException > >> > > > void deployAll(Collection<ServiceConfiguration> cfgs) > >> > > > throws ServiceDeploymentException > >> > > > > >> > > > The second method will delegate to deployAll(cfgs, false). This > way > >> in > >> > > the > >> > > > vast majority of cases user would not even bother about existence > of > >> > this > >> > > > flag. > >> > > > > >> > > > But let's go deeper. If I allowed partial deployment and several > >> > service > >> > > > failed - is it success or failure? On the one hand, it is a kind > of > >> > > success > >> > > > as I expected this, so I do not want exceptions. On the other hand > >> this > >> > > is > >> > > > a kind of failure, so Exception might be ok. All this makes API > >> hard to > >> > > > reason about. Personally I do not understand why user may want to > >> allow > >> > > > partial registration in practice. We should allow only > >> all-or-nothing > >> > > mode. > >> > > > And if something went wrong, we should return the list of > offending > >> > > > services in exception. This way API reduces to: > >> > > > > >> > > > void deployAll(Collection<ServiceConfiguration> cfgs) > >> > > > throws ServiceDeploymentException > >> > > > > >> > > > Clean, simple, covers 99% of real use cases. > >> > > > > >> > > > Thoughts? > >> > > > > >> > > > > >> > > > On Fri, Aug 18, 2017 at 4:16 AM, Dmitriy Setrakyan < > >> > > dsetrak...@apache.org> > >> > > > wrote: > >> > > > > >> > > > > Sounds good! Thanks for the detailed info. Can you please > provide > >> the > >> > > > > updated API in the ticket? > >> > > > > > >> > > > > On Thu, Aug 17, 2017 at 12:41 AM, Denis Mekhanikov < > >> > > > dmekhani...@gmail.com> > >> > > > > wrote: > >> > > > > > >> > > > > > > Can we add an "allOrNone" flag to the deployment method? > >> > > > > > > >> > > > > > Sounds good, I think we can. > >> > > > > > > >> > > > > > > However, hot do you ensure atomicity here? > >> > > > > > > >> > > > > > We can guarantee that if some of configurations are invalid, > or > >> a > >> > > > > > transaction, that writes configuration to the internal cache, > >> > fails, > >> > > > then > >> > > > > > no services will be deployed. > >> > > > > > > >> > > > > > Currently we don't track failures on the server side and > >> services > >> > are > >> > > > > > considered successfully deployed once their configurations are > >> > > written > >> > > > to > >> > > > > > the cache. So, it's not possible that all configurations are > >> valid, > >> > > but > >> > > > > > only a part of the services fail to deploy. If we change this > >> > > behavior > >> > > > > and > >> > > > > > start tracking failures during deployment and initialization > on > >> the > >> > > > > server, > >> > > > > > then we could automatically cancel services that are already > >> > deployed > >> > > > in > >> > > > > a > >> > > > > > batch. > >> > > > > > > >> > > > > > чт, 17 авг. 2017 г. в 8:34, Dmitriy Setrakyan <d...@gridgain.com > >: > >> > > > > > > >> > > > > > > On Wed, Aug 16, 2017 at 8:17 AM, Denis Mekhanikov < > >> > > > > dmekhani...@gmail.com > >> > > > > > > > >> > > > > > > wrote: > >> > > > > > > > >> > > > > > > > I've had a few off-line conversations with other Igniters > >> > > regarding > >> > > > > > this > >> > > > > > > > question and almost all of them think that services should > >> be > >> > > > > deployed > >> > > > > > > with > >> > > > > > > > "all-or-none" failing policy. > >> > > > > > > > We have a similar functionality for caches: > >> Ignite#createCaches > >> > > > > method > >> > > > > > > > don't allow partial deployments, and I think, we should > also > >> > > stick > >> > > > to > >> > > > > > > this > >> > > > > > > > principle for services. > >> > > > > > > > > >> > > > > > > > >> > > > > > > Can we add an "allOrNone" flag to the deployment method? If > >> true, > >> > > > then > >> > > > > > all > >> > > > > > > services will have to either be deployed or failed. However, > >> hot > >> > do > >> > > > you > >> > > > > > > ensure atomicity here? If you are deploying 10 services, and > >> > only 1 > >> > > > > > fails, > >> > > > > > > what do you do with the other 9, given that they have > already > >> > been > >> > > > > > deployed > >> > > > > > > and may have started serving API requests? > >> > > > > > > > >> > > > > > > > >> > > > > > > > > >> > > > > > > > Another question that I'd like to discuss here is that > >> > currently > >> > > > > > > > IgniteServices#deployAsync method may fail with an > exception > >> > > > instead > >> > > > > of > >> > > > > > > > returning a future. Shouldn't we change this behavior to > >> make > >> > > async > >> > > > > > > > operations always return a future whose get() method would > >> > throw > >> > > an > >> > > > > > > > exception? > >> > > > > > > > > >> > > > > > > > >> > > > > > > Makes sense to me. I think throwing exception from async > >> method > >> > is > >> > > > > plain > >> > > > > > > wrong. > >> > > > > > > > >> > > > > > > > > >> > > > > > > > вт, 15 авг. 2017 г. в 11:42, Dmitriy Setrakyan < > >> > > > > dsetrak...@apache.org > >> > > > > > >: > >> > > > > > > > > >> > > > > > > > > Denis, > >> > > > > > > > > > >> > > > > > > > > I don't think we need a king deployment result. > >> > > > > > > > > > >> > > > > > > > > The "deployAllAsync" method should never throw an > >> exception, > >> > it > >> > > > > > should > >> > > > > > > > > always return the future. However, the > >> IgniteFuture.get(...) > >> > > > method > >> > > > > > > does > >> > > > > > > > > throw an exception, and in this exception you should > >> provide > >> > > the > >> > > > > info > >> > > > > > > > about > >> > > > > > > > > the failures. > >> > > > > > > > > > >> > > > > > > > > D. > >> > > > > > > > > > >> > > > > > > > > On Tue, Aug 15, 2017 at 1:31 AM, Denis Mekhanikov < > >> > > > > > > dmekhani...@gmail.com > >> > > > > > > > > > >> > > > > > > > > wrote: > >> > > > > > > > > > >> > > > > > > > > > Dmitriy, thank you for your reply! > >> > > > > > > > > > > >> > > > > > > > > > I see a possibility of a bad scenario here. If we use > >> > > > > > deployAllAsync > >> > > > > > > > > method > >> > > > > > > > > > and it throws an exception, then the constructed > future > >> > won't > >> > > > be > >> > > > > > > > returned > >> > > > > > > > > > and we won't have a way to wait for the rest of the > >> > services > >> > > to > >> > > > > > > deploy. > >> > > > > > > > > > Maybe we should return some king of deployment result, > >> > > > > containing a > >> > > > > > > > > future > >> > > > > > > > > > along with a collection of failed services, instead of > >> > > throwing > >> > > > > an > >> > > > > > > > > > exception? > >> > > > > > > > > > > >> > > > > > > > > > пн, 14 авг. 2017 г. в 18:03, Dmitriy Setrakyan < > >> > > > > > > dsetrak...@apache.org > >> > > > > > > > >: > >> > > > > > > > > > > >> > > > > > > > > > > Hi Denis, I agree, we should have an API for batch > >> > service > >> > > > > > > > deployment. > >> > > > > > > > > My > >> > > > > > > > > > > comments are inline... > >> > > > > > > > > > > > >> > > > > > > > > > > On Mon, Aug 14, 2017 at 2:22 AM, Denis Mekhanikov < > >> > > > > > > > > dmekhani...@gmail.com > >> > > > > > > > > > > > >> > > > > > > > > > > wrote: > >> > > > > > > > > > > > >> > > > > > > > > > > > Hi Igniters! > >> > > > > > > > > > > > > >> > > > > > > > > > > > Currently Ignite doesn't have support for batch > >> service > >> > > > > > > deployment, > >> > > > > > > > > but > >> > > > > > > > > > > it > >> > > > > > > > > > > > may be a very useful feature in case of a big > >> number of > >> > > > nodes > >> > > > > > in > >> > > > > > > a > >> > > > > > > > > > > cluster > >> > > > > > > > > > > > and services to be deployed. Each deployment > >> includes > >> > > write > >> > > > > > into > >> > > > > > > an > >> > > > > > > > > > > > internal transactional cache, which is the longest > >> part > >> > > of > >> > > > > the > >> > > > > > > > > > procedure. > >> > > > > > > > > > > > > >> > > > > > > > > > > > I propose to optimize it by performing multiple > >> writes > >> > > in a > >> > > > > > > single > >> > > > > > > > > > > > transaction. It implies an introduction of a few > new > >> > > > methods > >> > > > > in > >> > > > > > > > > > > > IgniteServices interface. > >> > > > > > > > > > > > I am thinking about the following signatures: > >> > > > > > > > > > > > > >> > > > > > > > > > > > void deployAll(Iterable<ServiceConfiguration> > >> cfgs) > >> > > > throws > >> > > > > > > > > > > > IgniteException; > >> > > > > > > > > > > > IgniteFuture<Void> > >> > > > > > > deployAllAsync(Iterable<ServiceConfiguration> > >> > > > > > > > > > > > cfgs) throws IgniteException; > >> > > > > > > > > > > > > >> > > > > > > > > > > > I'd like to know your opinion on the following > >> > questions: > >> > > > > > > > > > > > > >> > > > > > > > > > > > - Do you agree with the proposed signatures? > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > Yes, but Iterable should be changed to Collection to > >> be > >> > > > > > consistent > >> > > > > > > > with > >> > > > > > > > > > > other similar APIs in Ignite. > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > - What should happen in case of a failure (some > >> of > >> > the > >> > > > > > > > > > configurations > >> > > > > > > > > > > > don't pass validation, or a service with > >> specified > >> > > name > >> > > > > but > >> > > > > > > > > > different > >> > > > > > > > > > > > configuration already exists)? Should partial > >> > > > deployments > >> > > > > be > >> > > > > > > > > > performed > >> > > > > > > > > > > > in > >> > > > > > > > > > > > case when some of them fail? > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > Yes, we should allow partial deployment. The > exception > >> > > thrown > >> > > > > > > should > >> > > > > > > > > > have a > >> > > > > > > > > > > collection of services that have failed deployment. > It > >> > > looks > >> > > > > like > >> > > > > > > you > >> > > > > > > > > > will > >> > > > > > > > > > > need to create ServiceDeploymentException (extends > >> > > > > > IgniteException) > >> > > > > > > > to > >> > > > > > > > > > > handle this case (in which case, you have to make > sure > >> > that > >> > > > > other > >> > > > > > > > > deploy > >> > > > > > > > > > > methods also throw it). > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > Regarding the second question I think that we > >> shouldn't > >> > > > > deploy > >> > > > > > > any > >> > > > > > > > > > > services > >> > > > > > > > > > > > in a batch if we encounter any problems with some > of > >> > > them. > >> > > > > > > > > > > > > >> > > > > > > > > > > > Also cancelAll method may be optimized in a > similar > >> > way, > >> > > > but > >> > > > > no > >> > > > > > > > > > interface > >> > > > > > > > > > > > changes are needed there. > >> > > > > > > > > > > > > >> > > > > > > > > > > > Ticket: https://issues.apache.org/ > >> > > jira/browse/IGNITE-5145 > >> > > > > > > > > > > > > >> > > > > > > > > > > > -- > >> > > > > > > > > > > > Cheers, > >> > > > > > > > > > > > Denis Mekhanikov > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > >> > > > > >
