Ignite Web Sessions Caching Failover question

[Siva Annapareddy <si...@gmail.com>]

We have two Node Apache Igniter Server cluster and Several Application client
nodes join the cluster.
If both Apache Ignite cluster nodes are down for some reason, is there a
config to set up to fallback to a scenario where Application nodes store web
Session in their own JVM and continue transparently without causing much
pain to the users of the Application?



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Re: Ignite Web Sessions Caching Failover question

[vdpyatkov <vl...@gmail.com>]

Hi,

If Ignite server is fail down at some moment, you prevent to loose data only
if you have enough node with backups.
But if your whole cluster is down, you surely got a fail in web application.


Siva Annapareddy wrote
>   Application nodes store web Session in their own JVM

Real user can address request to Application cluster through front-end
server (like NGINX). In general case we can not know where user will be
redirected.
How will it be work?




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Re: Ignite Web Sessions Caching Failover question

[Sasha Belyak <rt...@gmail.com>]

I think it's very interesting use case (if I understand you correctly) to
store data locally and, if client can, connect to the cluster and share
data. But for now this use case doesn't support directly and, probably, you
should put some local write behind cache before apache ignite client node
and work with this cache from you app. Cache should:
1) Have some evict policy for prevent overflowing of local JVM memory
2) Trying to write cached data in background to put all data into your
cluster when it available

Re: Ignite Web Sessions Caching Failover question

[vkulichenko <va...@gmail.com>]

Hi Rishi,

I'm not sure I understand your concerns. First of all, web session
clustering is not always used with Spring Boot. We just provide a web filter
which can be used in any servlet based application. Second of all, the
filter currently blocks with timeout or fails with exception in case client
disconnected from cluster. Basically, if server nodes are down, application
is not functional, which is in many cases wrong. One may want to increase
application availability buy paying with potential loss of session data. Of
course, it has to be a configurable option.

-Val



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Re: Ignite Web Sessions Caching Failover question

[ignite_user2016 <ri...@gmail.com>]

Hello Val,

I did looked at this possibility but this is something needs to be done on
Spring boot side so spring boot should provide us the capability to manage
user session in memory when the distributed cache cant get connected, kind
of a fall back mechanism.

I still believe this is something distributed cache cant do OR should not do
however it can have the failure handlers which would tell spring boot to
manage sessions in memory.

The usecase gets more complicated when a user session does fall back on
memory and now ignite comes up then the framework shall do the session
replication on ignite and vice versa..

Hope it helps..

Thanks,
Rishi





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Re: Ignite Web Sessions Caching Failover question

[vkulichenko <va...@gmail.com>]

It seems that it will always throw an exception in this scenario. However it
makes sense to me, are you willing to contribute this improvement?

-Val



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