I set up two equal tomcat servers that host the same web application (Sun RI JSF 2 / Tomahawk). For load balancing and fail-over scenarios I use an nginx server as reverse proxy delegating the request to the one or the other server. Right now one tomcat is defines as backup solution, so that tomcat server 1 handles all the requests. When I kill the process of tomcat 1, nginx nicely delegates the following requests to tomcat server 2. In order to reuse the session data I configured both tomcat servers to use memcached as session store. JSF is configured to store its state on the server.
Concerning the log files, this setup looks quite nice and session data is read and stored using the memcached server. This for example facilitates using the web application without the need to login again even if tomcat 1 has been shut down.
Nevertheless it seems as if my (session scoped) backing beans are not stored or being used after restoring the session respectively. Form fields are left empty that are supposed to be filled with the data from the session bean.
Is it possible to do such things with the mentioned technologies at all?
With memcached-session-manager and OWB you should use tomcat < 7.0.22 as in this version the notification of ServletRequestListeners got changed (which is the mechanism used by OWB for failover support).
I'm currently working on a new version of msm that works with OWB and tomcat >= 7.0.22.
Related
We have written simple message sending mechanism to client (logged in user based) from server by using spring boot + websocket.
Currently its running in a single server, which is working fine.
But our production servers running under load balancing environment.
How could we achieve where the messages are pushed from server nodes send to appropriate users.
Please advice the possibilities, I have read some articles about RabbitMQ with socketjs , but not clear will it work for load balancing.
Thanks
If you have multiple instances of your websocket server, then every instance needs to know the sessions that exists on other instances.
Therefore you need to use a broker relay (not the in-memory broker given by spring) and set the UserRegistryBroadcast property.
You can find some info related to this at the end of this talk https://www.youtube.com/watch?v=nxakp15CACY
My spring boot restful web services is working even though stopped running microsoft sqlserver database in my services. How does it work?
There might be below reason.
You might be using some kind of cache so still response is coming form cache even your db is down.
You might be checking services which are not required db transaction..
OR if you are only referring you application is continue to running then might be spring.datasource.continue-on-error=true has been set. or you might have some defined data source validations properties to at-least continue run app and whenever db is back, it will established a connection.
We have started using infinispan cache with wildfly 13 in our web application. The web application is deployed in wildfly domain mode in a cluster of two node with one acting as master and the other as slave. In the application we have an admin feature, where the admin can terminate a user.
So what we want to do is add session objects to Infinispan cache and retrieve it and terminate it when required. I am aware that HttpSession object is not serializable hence it cannot be added to cache but every attribute added to the session object is serilizable so my question is, is there a workaround for the issue? Because right now we get a NotSerializable error when I try to add session to cache and it's also no longer possible to retrieve session from sessionId and terminate it due to security reasons.
There is no need to manually interact with the Infinispan cache: WildFly transparently supports full http session clustering with Infinispan. See https://docs.jboss.org/author/display/WFLY10/High+Availability+Guide
We have environment with two Apache Web Server and Two Tomcat via Mod_jk. We have configured Both to Apache for Loadbalancer as well as failover.
We have a LB on top of both the Apache web Server configured in Round Robin Algorithm
Problem is randomly session gets invalidated when both the apache are running .
If One of the Apache is running loadbalancing and failover works perfectly fine.
Do i need to configure a two apache web server ?
Do i need to change some configuration for two apache for sticky session ?
our prod environment architecture is decided to be like this:
2 machines that each of them have 2 tomcat instances (on vm). there is spring web app with hibernate running on tomcat.
there are also 2 db instances distributed to both machines.
so, we think that hazelcast fits this achitecture well. hazelcast will be second level cache for hibernate, it will manage clustered cache over db instances.
we installed hibernate server and defined our clusters on it.
i've searched offical hazelcast doc and several sites but i couldnt find the way to configure hibernate to use this hazelcast server as L2 cache.
we dont want to change our existing app. we'll keep using hibernate as it is. is it possible? if so, how we can configure hazelcast server on our web app?
I think it is important to understand that your probably don't want to have a standalone Hazelcast cluster/server; what you normally do is to embed Hazelcast within your application.
Like Miko said, you can just enable Hazelcast to be used as second level cache; no need to make any fundamental changes.
I also don't understand what you mean with 'hibernate server', because Hibernate is just an OR mapper library and has no concept of server.
So can you tell a bit more what you want so we can help you out?