If I have 2 instances of service A implemented using spring-data-rest that register themselves in spring-cloud eureka and client app B using Ribbon client-side load balancing would HAL links inside A responses be load balanced by Ribbon when B follows them ?
PS: I know I could build a prototype to test myself but I'm strapped for time.
Thanks in advance.
First of all, feign is only the http-client side of it, Ribbon does the load balancing.
Load balancing is possible if the feign clients are registered with a serviceId and not an actual host.
I am not sure what you mean by following, but if you are referencing an actual host in the links (and not serviceId-s) ribbon won't loadbalance.
I think this thread relates to your question:
Linking between objects on different apps with Spring HATEOAS
Related
I am trying to deploy 2 containers on 2 different tasks (1 container per task), one is my frontend and the other is my backend server. I am trying to figure out how to configure the communication between them.
I saw that a load balancer in a service is a good option. However, should I configure load balancer for my front end server and another one for my backend? Meaning each time I have public-facing services and private services I need 2 load balancers?
I would like to only expose my front-end to the public internet and my backend will remain private (although I make API requests to the outside world - probably need to configure outbound route too?).
I would highly appreciate any information.
No you don't need a private LB for that. It is an option you can use but ECS has since introduced the concept of Service Discovery for back-end services. The idea is that your front end is exposed to your users via a standard LB (e.g. ALB) but services that are being called by the front end and that run behind the scene can be addressed using this service discovery mechanism (based on Route53/CloudMap).
You can see an example of this concept here. This CFN template gives you the details re how you can build this layout.
can anyone point me to a resource, how I can get spring-webflux and javamelody to work together?
Seems, that a servletcontext is neccessary for startup, which I don't have/need.
I'm aware of the coll metrics stuff, that comes with spring-boot 2.x, but I don't have anything to display the metrics with, and am locked to a company environment, where just installing something isn't a valid option.
Thanks,
Henning
javamelody is mainly based on monitoring of memory, cpu, http requests, sql requests and spring components among other things. See javamelody-spring-boot-starter for example.
But as far as I know, Spring webflux does not use the servlet api. So what do you want to monitor?
If you just want to have graphs in a browser, then start a http server for javamelody reports like in standalone. And if you also want to monitor sql requests and spring components, then add in your application all methods from this example, except monitoringSessionListener and monitoringFilter.
A new spring-boot-starter for javamelody in webflux could be created if it makes sense.
I am currently evaluating solutions for WCF Webservice HA with load balancing. I see 2 feasible approaches for the type of WS i am authoring which are
1) Using the RoutingService API / Class provided by .NET
2) Using a HTTP load balancer like nginx.
Which one is a better approach for WCF WS hosted on IIS.
It depends on a lot of factors. The main one being, is the load balancing requirement a pure availability/scalability driven requirement or is it a business requirement?
If you simply require scale, eg a round robin distribution, or high availability, eg. active/passive failover, and you already have a network load balancer in front of your servers, then I would definitely use that.
The simple reason is that then it will be looked after by your infrastructure people, which is how it should be. Load balancing for scale/availability etc is not normally a development concern.
However, if you have a requirement for routing based on message content, eg routing of high priority calls to one endpoint only, or meeting call processing SLAs for different content, then this becomes a business requirement, because routing logic will then be determined on the business context of the call.
This most definitely is a development concern. In this instance I would certainly use the routing service to implement these various business cases.
Hope this helps you.
We have WCF service X: deployed on server A and Server B, host address:
http://127.0.0.1:8777/ServiceX/
And we load balance the two servers. We accesss the service via http://myappserver/ServiceX
We need to use per-session mode, and we set [reliable sessions] as true:
We don't find any issue till now based on testing. But the below linked MSDN article says that Do not use reliable sessions for Load Balancing with the WSHttp Binding? Please can someone give more details? Thanks a lot.
WCF Load Balancing http://msdn.microsoft.com/en-us/library/ms730128.aspx
Reliable Messaging means all your messages from your established client reach the same endpoint behind any intermediaries like routers and load balancers.
Load balancing means your calls will be distributed across all nodes as the load balancer sees fit.
Those two goals are mutually exclusive. You can have one or the other, not both.
I have not had time to try this myself yet, but I found this old blog entry (https://blogs.msdn.microsoft.com/drnick/2007/07/13/sticky-sessions/):
This division according to groups would allow a feature like reliable messaging to work because the same server would be used to process all of the messages in the reliable session. The feature that this division method represents is typically called “sticky sessions” or some other phrase for affinitization in the load balancer.
Given that you mention that your firewall supports sticky sessions, I suspect/hope you will be fine.
I'm designing a software system which has some C++ projects and java web applications hosted on Apache/Tomcat. Native code[C++ outputs] will connect to other systems[DB, External Gateways, etc] through web apps as HTTP requests. In order to make a good distributed/modular system, I'm planning to use several [5 to 10] web applications.
But still my system is not finished its developments, but function enough to sell. But even still 20% of its full features, I have to go through a huge deployment procedure since it has much of web apps.
My question is,
Is it good to merge few web apps TEMPORARILY to reduce deployment overhead[I can do this till I get a significant larger source for each] and do http requests within that same web application?
Will it be cause any performance/memory/threading issue?
if you are merging two or three web components and want to deploy an single jvm
than you should not use http request between web components,
for this you can use jboss osgi http://www.jboss.org/jbossas/subprojects/osgienter link description here
The solution I found was to use a hosted JVM, which is an application on either a Servlet container or in a web service.
This way, a single JVM is re-used.
But the problem here is that, you need a communication mechanism between two applications, which I prefer of using TCP sockets.