I have a few instances of Spring apps running behind a load balancer. I am using EHCache as a caching system on each of these instances.
Let's say I receive a request that is refreshing a part of the cache on one instance. I need a way to tell the other instances to refresh their cache (or to replicate it).
I'm more interested in a solution based on Spring and not just cache replication and that's because there are other scenarios similar with this one that require the same solution.
How can I achieve this?
There is no simple Spring solution for this. Depends on the requirements. You can use any kind of PubSub like a JMS topic to notify your nodes. This way the problem can be that you cannot guarantee consistency. The other nodes can still read the old data for a while. In my current project we use Redis. We configured it as cache with Spring Data Redis and theres no need to notify the other nodes since the cache is shared. In non cache scenarios we also use redis as a PubSub service.
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I am new to Microservices. (Learning phase). I have a question. We deploy microservices at cloud. (e.g. AWS). Cloud already provide load balancing and logs. And We also implement Load Balancing(Ribbon) and logs(Rabbit MQ and Zipkin) in Spring Boot.
What is the difference in these two implementation? Do we need both?
Can some answer these questions.
Thanks in advance.
Ribbon is a client side load balancer which means there is no any other hop in between your client and service. Basically you keep and maintain a list of service on your client.
In AWS load balancer case you need to make another hop in between the client and server.
Both have advanges and disadvantages. Former has the advantage of not having any dependency to any specific external solution. Basically with ribbon and service discovery like eureka you can deploy your product to any cloud provider or on-premise setup without additional effort. Latter has advantage of not needing an extra component of service discovery or keeping the cache of service list on client. But it has that additional hop which might be an issue if you are trying to run an very high-load system.
Although I don't have much experience with AWS CloudWatch what I know is it helps you to collect logs to a central place from different AWS components. And that is what you are trying to do with your solution.
I have a Spring Boot application that uses MongoDB. My plan is to store data in a distributed caching system before it gets inserted into Mongo. If the database fails, the caching will have a queue and send to the DB once it is up. So, the plan is to make the caching layer in between the application and Mongo.
Can you suggest some ideas on how to implement this using Apache Ignite?
Take a look at write-behind cache store mode. It retries writing to the underlying database if insertion to the underlying DB fails. Let me know how it works for you.
You can also implement a custom CacheStore for an Ignite cache that will do the caching and enable write through for it. If the connection is lost, then you'll be able to collect entries in a buffer, while retrying to establish the connection back.
See more: https://apacheignite.readme.io/docs/3rd-party-store
I am trying to deploy a spring-security server, with Redis as token store.
In order to have some redundancy in Redis, we want to deploy it as a cluster.
The problem is Jedis, which is used by spring security as underlying library, doesn't support pipelining in cluster mode, but spring security uses pipelining.
My question is how can I solve this situation. More precisely:
1- Should I use another mode of deployment form Redis? What actually works.
2- Can I somehow force spring security to use reddison for connecting to Resid?
Please adivse.
If you want redundancy, use replication (master/slave) not cluster.
If you have more data than RAM on a machine, use cluster.
If you have more data than RAM on a machine and want redundancy, use cluster with replication.
Jedis supports replication with sentinel, so give that a go unless you have a lot of data. Some more info on usage here: https://github.com/xetorthio/jedis/issues/725
We deploy two service instance in difference machine using CXF distributed OSGi. we want to give the system the load balancing feature. All we know the OSGi don't provide any load balancing feature. Does anyone know how to do it ?
Load balancing is a concern that is meant to be implemented by the Topology Manager (TM). It would be useful to read the Remote Services Admin specification, which addresses exactly this kind of question.
As far as I know, the CXF implementation of Remote Services only implements a single TM, which is "promiscuous", i.e. it publishes every available service in every listening framework. It is possible however to write your own TM to perform load balancing and failover etc.
The Remote Services spec is written in such a way that a TM implementation can be developed completely independently of any specific Remote Services implementation.
You should be able to get the complete list of services using a ServiceTracker. So a nice way to create a load balancer should be to create a proxy service yourself that does the load balancing and publish it locally as a service with a special property. So your business application can use the service without knowing anything about the details of load balancing.
I am looking to implement a web application in which the end user is likely to cause invocation of business logic methods which are both cpu heavy and require a fair amount of memory to run.
My initial thought is to provide these methods as part of a standalone stateless business service, which can run on a separate machine to the web application. This can then be horizontally scaled as much as I need.
As these service methods are synchronous I am opting to us RMI as opposed to JMS.
My first question is if the above approach seems viable or seems to be good, or if my though process has got lost somewhere (this will be the first time I don't work on a standalone application).
Should that be the case I have been looking at spring RMI which seems to do an excellent job of exposing remote services non-intrusively. However I am unsure as how I could use this API to load balance between multiple servers. Are there any ways of doing this using spring or do I need a seperate API?
JBoss has the ability provide RMI proxies that are automatically load-balanced: http://docs.jboss.org/jbossas/jboss4guide/r4/html/cluster.chapt.html