It sounds like it's not a trivial thing to support the automatic services redeployment after a restart. Let's postpone it for now, guys concentrating on more urgent things related to the services.
Alex, Vladimir, Could you have a look at Denis question about the discovery-based deployment? Guess it's the only one thing that prevents us from the IEP finalization. -- Denis On Fri, Apr 13, 2018 at 5:30 AM, Denis Mekhanikov <dmekhani...@gmail.com> wrote: > Vladimir, > > Currently we don't save binary metadata to disk, when persistence is > disabled. > But we still persist marshaller mappings for some reason, and I personally > believe, that we shouldn't. > > But I agree, that we should separate data and service persistence > configuration. > Right now persistence of services is configured in a pretty non-obvious > manner. > It should be a clear way to tell Ignite, whether you want services to be > persisted or not. > > I'm not sure, that we should make "statefullness" in general configurable. > Users don't care much, whether metadata is preserved on restarts, or not. > > Denis > > пт, 13 апр. 2018 г. в 14:29, Vladimir Ozerov <voze...@gridgain.com>: > > > Alex, > > > > I would say that we've already had this behavior for years - marshaller > > cache. I think it is time to agree that "in-memory" != stateless. Instead > > "in-memory" means "data is not stored on disk". > > May be we can have a flag which will wipe out all metadata on node > restart > > (e.g. it could make sense for embedded clients)? > > > > On Fri, Apr 13, 2018 at 12:48 PM, Alexey Goncharuk < > > alexey.goncha...@gmail.com> wrote: > > > > > Denis, > > > > > > This is a subtle question. It looks like we have now a number of > > use-cases > > > when persistent storage is required even for a pure in-memory mode. One > > of > > > the use-cases is thin client authentication, the other is service grid > > > configuration persistence. > > > > > > Generally, I would agree that this is an expected behavior. However, > this > > > means that a user cannot simply start and stop nodes randomly anymore. > > > Ignite start will require some sort of installation or work folder > > > initialization (sort of initdb in postgres) which is ok for > > > persistence-enabled modes, but I am not sure if this is expected for > > > in-memory. Of course, we can run this initialization automatically, but > > it > > > is not always a good idea. > > > > > > If we are ok to have this restrictions for in-memory mode, then service > > > persistence makes sense. > > > > > > --AG > > > > > > 2018-04-11 22:36 GMT+03:00 Denis Magda <dma...@apache.org>: > > > > > >> Denis, > > >> > > >> I think that the service deployment state needs be persisted > > cluster-wide. > > >> I guess that our meta-store is capable of doing so. Alex G., Vladimir, > > >> could you confirm? > > >> > > >> As for the split-brain scenarios, I would put them aside for now > > because, > > >> anyway, they have to be solved at lower levels (meta store, discovery, > > >> etc.). > > >> > > >> Also, I heard that presently we store a service configuration in the > > >> system > > >> cache that doesn't give us a way to deploy a new version of a service > > >> without undeployment of the previous one. Will this issue be addressed > > by > > >> the new deployment approach? > > >> > > >> -- > > >> Denis > > >> > > >> On Wed, Apr 11, 2018 at 1:28 AM, Denis Mekhanikov < > > dmekhani...@gmail.com> > > >> wrote: > > >> > > >> > Denis, > > >> > > > >> > Sounds reasonable. It's not clear, though, what should happen, if a > > >> joining > > >> > node has some services persisted, that are missing on other nodes. > > >> > Should we deploy them? > > >> > If we do so, it could lead to surprising behaviour. For example you > > >> could > > >> > kill a node, undeploy a service, then bring back an old node, and it > > >> would > > >> > make the service resurrect. > > >> > We could store some deployment counter along with the service > > >> > configurations on all nodes, that would show how many times the > > service > > >> > state has changed, i.e. it has been undeployed/redeployed. It should > > be > > >> > kept for undeployed services as well to avoid situations like I > > >> described. > > >> > > > >> > But it still leaves a possibility of incorrect behaviour, if there > > was a > > >> > split-brain situation at some point. I don't think we should precess > > it > > >> > somehow, though. If we choose to tackle it, it will overcomplicate > > >> things > > >> > for a sake of a minor improvement. > > >> > > > >> > Denis > > >> > > > >> > вт, 10 апр. 2018 г. в 0:55, Valentin Kulichenko < > > >> > valentin.kuliche...@gmail.com>: > > >> > > > >> > > I was responding to another Denis :) Agree with you on your point > > >> though. > > >> > > > > >> > > -Val > > >> > > > > >> > > On Mon, Apr 9, 2018 at 2:48 PM, Denis Magda <dma...@apache.org> > > >> wrote: > > >> > > > > >> > > > Val, > > >> > > > > > >> > > > Guess we're talking about other situations. I'm bringing up the > > case > > >> > > when a > > >> > > > service was deployed dynamically and has to be brought up after > a > > >> full > > >> > > > cluster restart w/o user intervention. To achieve this we need > to > > >> > persist > > >> > > > the service's configuration somewhere. > > >> > > > > > >> > > > -- > > >> > > > Denis > > >> > > > > > >> > > > On Mon, Apr 9, 2018 at 1:42 PM, Valentin Kulichenko < > > >> > > > valentin.kuliche...@gmail.com> wrote: > > >> > > > > > >> > > > > Denis, > > >> > > > > > > >> > > > > EVT_CLASS_DEPLOYED should be fired every time a class is > > deployed > > >> or > > >> > > > > redeployed. If this doesn't happen in some cases, I believe > this > > >> > would > > >> > > > be a > > >> > > > > bug. I don't think we need to add any new events. > > >> > > > > > > >> > > > > -Val > > >> > > > > > > >> > > > > On Mon, Apr 9, 2018 at 10:50 AM, Denis Magda < > dma...@apache.org > > > > > >> > > wrote: > > >> > > > > > > >> > > > > > Denis, > > >> > > > > > > > >> > > > > > I would encourage us to persist a service configuration in > the > > >> meta > > >> > > > store > > >> > > > > > and have this capability enabled by default. That's > essential > > >> for > > >> > > > > services > > >> > > > > > started dynamically. Moreover, we support similar behavior > for > > >> > > caches, > > >> > > > > > indexes, and other DDL changes happened at runtime. > > >> > > > > > > > >> > > > > > -- > > >> > > > > > Denis > > >> > > > > > > > >> > > > > > On Mon, Apr 9, 2018 at 9:34 AM, Denis Mekhanikov < > > >> > > > dmekhani...@gmail.com> > > >> > > > > > wrote: > > >> > > > > > > > >> > > > > > > Another question, that I would like to discuss is whether > > >> > services > > >> > > > > should > > >> > > > > > > be preserved on cluster restarts. > > >> > > > > > > > > >> > > > > > > Currently it depends on persistence configuration. If > > >> persistence > > >> > > for > > >> > > > > any > > >> > > > > > > data region is enabled, then services will be persisted as > > >> well. > > >> > > This > > >> > > > > is > > >> > > > > > a > > >> > > > > > > pretty strange way of configuring this behaviour. > > >> > > > > > > I'm not sure, if anybody relies on this functionality > right > > >> now. > > >> > > > Should > > >> > > > > > we > > >> > > > > > > support it at all? If yes, should we make it configurable? > > >> > > > > > > > > >> > > > > > > Denis > > >> > > > > > > > > >> > > > > > > пн, 9 апр. 2018 г. в 19:27, Denis Mekhanikov < > > >> > > dmekhani...@gmail.com > > >> > > > >: > > >> > > > > > > > > >> > > > > > > > Val, > > >> > > > > > > > > > >> > > > > > > > Sounds reasonable. I just think, that user should have > > some > > >> way > > >> > > to > > >> > > > > > know, > > >> > > > > > > > that new version of a service class was deployed. > > >> > > > > > > > One way to do it is to listen to *EVT_CLASS_DEPLOYED. > *I'm > > >> not > > >> > > > sure, > > >> > > > > > > > whether it is triggered on class redeployment, though. > If > > >> not, > > >> > > then > > >> > > > > > > another > > >> > > > > > > > event type should be added. > > >> > > > > > > > > > >> > > > > > > > I don't think, that a lot of people will implement their > > own > > >> > > > > > > > *DeploymentSpi*-s, so we should make work with > > >> > *UriDeploymentSpi* > > >> > > > as > > >> > > > > > > > comfortable as possible. > > >> > > > > > > > > > >> > > > > > > > Denis > > >> > > > > > > > > > >> > > > > > > > пт, 6 апр. 2018 г. в 23:40, Valentin Kulichenko < > > >> > > > > > > > valentin.kuliche...@gmail.com>: > > >> > > > > > > > > > >> > > > > > > >> Yes, the class deployment itself has to be explicit. > > I.e., > > >> > there > > >> > > > has > > >> > > > > > to > > >> > > > > > > be > > >> > > > > > > >> a manual step where user updates the class, and the > exact > > >> step > > >> > > > > > required > > >> > > > > > > >> would depend on DeploymentSpi implementation. But then > > >> Ignite > > >> > > > takes > > >> > > > > > care > > >> > > > > > > >> of > > >> > > > > > > >> everything else - service redeployment and restart is > > >> > automatic. > > >> > > > > > > >> > > >> > > > > > > >> Dmitriy Pavlov, all this is going to be disabled if > > >> > > DeploymentSpi > > >> > > > is > > >> > > > > > not > > >> > > > > > > >> configured. In this case service class definitions have > > to > > >> be > > >> > > > > deployed > > >> > > > > > > on > > >> > > > > > > >> local classpath and can't be updated in runtime. Just > > like > > >> it > > >> > > > works > > >> > > > > > > right > > >> > > > > > > >> now. > > >> > > > > > > >> > > >> > > > > > > >> -Val > > >> > > > > > > >> > > >> > > > > > > >> On Fri, Apr 6, 2018 at 10:20 AM, Dmitriy Setrakyan < > > >> > > > > > > dsetrak...@apache.org > > >> > > > > > > >> > > > >> > > > > > > >> wrote: > > >> > > > > > > >> > > >> > > > > > > >> > On Fri, Apr 6, 2018 at 9:13 AM, Dmitry Pavlov < > > >> > > > > > dpavlov....@gmail.com> > > >> > > > > > > >> > wrote: > > >> > > > > > > >> > > > >> > > > > > > >> > > Hi Igniters, > > >> > > > > > > >> > > > > >> > > > > > > >> > > I like automatic redeploy which can be disabled by > > >> config > > >> > if > > >> > > > > user > > >> > > > > > > >> wants > > >> > > > > > > >> > to > > >> > > > > > > >> > > control this process. What do you think? > > >> > > > > > > >> > > > > >> > > > > > > >> > > > >> > > > > > > >> > I do not think we should have anything automatic when > > it > > >> > comes > > >> > > > to > > >> > > > > > > >> > deployment, everything should be explicit. However, > if > > we > > >> > use > > >> > > > the > > >> > > > > > > >> > deployment SPI, then a user should be able to do > "hot" > > >> > > redeploy, > > >> > > > > > > where a > > >> > > > > > > >> > new service will be deployed if the user drops an > > updated > > >> > jar. > > >> > > > > > > >> > > > >> > > > > > > >> > We should not create anything new here. Ignite > already > > >> has a > > >> > > > > > > deployment > > >> > > > > > > >> SPI > > >> > > > > > > >> > and it already works in a certain way. Let's not > change > > >> it. > > >> > > > > > > >> > > > >> > > > > > > >> > D. > > >> > > > > > > >> > > > >> > > > > > > >> > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > >> > > > >> > > > > > > > > >
