Can I use SOA and three-tier in one application? Using SOAP to connect for external services, using MQ and Spring MVC. I have an application server and server for the database.
Yes, it seems that they are very different things.
There is a vast array of different SOA implementation styles, you can do it in so many ways. One is to have services talking to APIs over http where the APIs in question are written in a 3 tier style.
You can also have an event driven architecture where messages are passed on a message bus or a queue or some sort, the services reading and writing to those queues can be written in a three-tier style.
To sum up yes you can have SOA and three-tier in the same architectural solution, one does not exclude the other.
Does this help your decision on how to structure your service design and how to structure the wider solution architecture?
Is it advicible to build the MSA based services on Oracle SOA or any other ESB suite for that matter? Is there any advantage or disadvantage?
If I am using Java, Spring and JPA over a message queue - say - RabbitMQ, I can achieve it in a more controlled environment with less recurring expenses. Of course will end up mixing tools like Drools or JBPM or similar to achieve things that may be OOTB (Out of the box) in the SOA Or ESB Suite. But scaling a specific service without paying licence fee for an additional environment should certainly be a good catch right?
Microservices architecture pattern applies to development of backend systems/services, whereas ESB (e.g. Oracle SOA Suite) is intended as an intermediary layer between consumers and backend services. Backend services contain rich application logic, whereas ESB services provide only intermediary functions like routing, transformation, orchestration etc.
ESB is not intended for rich application logic, though it's possible to do that.
Using ESB (e.g. Oracle SOA Suite) to host microservices is achievable, but you will get a big overhead comparing to limited functions and scalability. If you are looking for centralized API management (tracing, security etc.), you can put an API gateway into your architecture instead of full scale ESB.
I study SOA and webservices for a science paper. My state of knowledge is, that every SOA architcture needs a service broker.
Webservices are concrete implementations of a SOA, so do they have a service broker after? For example I create a webservice in asp.net which returns "hallo world" By Creating it, do I create a service broker too?
Don't let fool you by answers which are copy paste from Wikipedia :-)
Webservices are concrete implementations of a SOA
This assumption/statement is wrong. At least there is no direct relationship between SOA and webservices. SOA is an architectural paradigm where a webservice is a concrete technology (stack) based on WSDL and its result, the SOAP-protocol. Nothing more. Webservices may help to establish loosely coupled service landscape, which the SOA paradigm expects. But you could also build up a SOA landscape with other technology stacks (self-written hacks, RMI, even based on REST for instance).
Repository
The thing is: When you start building up your SOA-landscape, you (or others) will code services (i.e. webservices) where your service will have a technical contract (WSDL, WADL, ..) as a base for the implementation. Your clients will ask for it and you want it to store somewhere. This somewhere is usually a service repository. You could develop your own one, use the UDDI-standard or just buy one of products by the big vendors (IBM, TIBCO, Oracle etc).
Broker
A message broker within the SOA context is some piece of software, which supports the decoupling of the connected partner systems. Commonly it's called ESB (enterprise service bus). Also one of the goals of the SOA paradigm is, that the services can be used by anyone (reusability). Therefore you don't want to connect your services by P2P-connections (aka spaghetti architecture) - just imagine that one of the service participants changes it's hardware/IP: this would be a nightmare for all the connected partner systems. That's why the ESB was invented which acts between the service consumer and the service provider.
Typically, these ESB-products support a lot of technologies or -stacks/APIs like HTTP, JMS, REST etc.
Source: I work with a self-claimed SOA landscape and thousands of different (web-)services for a big company for a long time now.
A Web service is a set of related application functions that can be programmatically invoked over the Internet. Businesses can dynamically mix and match Web services to perform complex transactions with minimal programming. Web services allow buyers and sellers all over the world to discover each other, connect dynamically, and execute transactions in real time with minimal human interaction.
Web services are self-contained, self-describing modular applications that can be published, located, and invoked across the Web.
A network component in a Web Services architecture can play one or
more fundamental roles: service provider, service broker, and service
client.
Service brokers register and categorize published services and provide search services. For example, UDDI acts as a service broker for WSDL-described Web services.
I am looking into architectural patterns, Enterprise Services Bus (ESB) precisely. Upon reading this article Enterprise Integration, and with little to no experience I am wondering if BizTalk has is a ESB or is it just a EAI (Hub/Spokes or Bus)?
I found this NServiceBus and Biztalk, describing BizTalk as a central message broker.
Taking other ESB frameworks into account (NServiceBus and Rhino Service Bus). These frameworks have no central point to process messages.
Is Biztalk a EAI rather than an ESB?
Many thanks
BizTalk is punted by Microsoft as having ESB capabilities - see the BTS ESB toolkit
However, the term 'ESB' covers a very broad field, and there is a lot of subjectivity about an exact definition of an ESB. IMHO there are weak points in BizTalk's claim to be comprehensive as an ESB (in a > 2010 definition of the term).
BTS originated in the Hub-and-Spoke EAI era, before ESB became widespread.
BTS is more suited toward asynchronous processes than synchronous processes - latencies will vary depending on load on the system, throttling state, etc.
BTS is cumbersome when it comes to ease of versioning of services and schemas (new deployment is needed)
BTS is cumbersome when it comes to management of MANY services (e.g. Using BizTalk as a facade for all 5000 of your corporate SOA / Web Services will be painful)
FWIW we have found BTS a good fit for:
all of our synchronous and asynchronous EAI (i.e. formalized integration contracts between major LOB systems, and with trading partners), and the large number of adapters assists with integrating a wide number of protocols.
For Business Process and Business Monitoring capabilities
Addressing transactional and delivery reliablity - Biztalk has capability to retry, tracking and resumption of Suspended messages, which is useful over unreliable networks or when it comes to integration with unreliable systems.
Update, with some further comparative experiences
BTS is very centralised - ultimately, even a multi-server BizTalk cluster / group is dependent on Sql-Server. Queue based ESB products tend to be more decentralised (logically and physically), so loss of a few endpoint or queue servers should not pull the whole enterprise down.
Many queue based ESB's are built on open source technologies, with an eye on avoiding single vendor lock-in
Many contemporary ESB's seem to take a commodity-computing approach to scale out. Scaling out with products like BizTalk can become expensive.
On the plus side, the monitoring and administration capabilities of commercial offerings like BTS should not be underestimated - make sure any ESB you are considering has adequate auditing, instrumenting, retry, and diagnostic (WMI / SNMP / SCOM etc) capabilities - you'll need a dashboard to monitor the health of your bus, and there is nothing worse than not knowing where a message went. Here, centralisation administration and diagnosis is a plus.
BizTalk is a messaging and workflow orchestration platform, on which you can build ESB behaviours and capabilities. To make this easier, and standardise ESB implementation on BizTalk, Microsoft released the BizTalk ESB Toolkit - a set of guidelines, patterns and code.
The concepts of EAI and BPM have been around for a while, so there are many companies that have leveraged BizTalk to create solutions to these problems. Companies that host a full ESB on BizTalk server are far fewer, and adoption has certainly slowed in the advent of WCF/WF/NServiceBus and, of course, Azure Service Bus.
So in summary, BizTalk out of the box is nether EAI or ESB, but can do both with a number of developers applied to the problem.
By "EAI or ESB" I'm assuming you wanted to know if BizTalk follows the Hub&Spoke or the Bus architecture.
From an architecture patterns perspective, integration solutions roughly fall under one of the two patterns-
The Hub and spoke:
This involves a centralized message broker sending out messages to various receivers, while all the senders send their messages only to this broker.
Thus neither the senders nor the receivers need to be aware of each other.
This is typically what many people refer to as EAI (although it is absolutely possible to implement an EAI solution that follows the BUS pattern).
Solutions following this pattern are easy to develop and administer. All the routing logic is centrally managed at one place - in the hub.
But as you would have guessed, this has a glaring drawback - single point of failure. If the hub crashes everything comes to a halt. Also, this model doesn't scale very well.
BUS:
Enterprise Integration solutions developed around this pattern are generally referred to as ESB. There is no intelligent central authority here. All senders publish their messages on the bus. The receivers need to be intelligent enough to determine which messages are intended for them and take them off the bus.
Thus the senders and the receivers need only be aware of the bus. But here the routing logic is spread across the receivers so there is no single point of failure. Also this model is highly scalable. However such solutions are quite complex and difficult to administer.
Coming to the question which pattern does BizTalk follow- it is a hybrid of both these patterns.
the Hub-like appearance is very obvious with its centralized Messaging Engine, and a central MessageBox database. This gives one the simplicity and ease of administration which is typical of the hub approach.
But if you look at the BizTalk architecture, one can have a Host with its Host Instances spread across multiple servers. It is also possible to have the different BizTalk databases like MessageBox, Tracking, Ent SSO etc. configured on different servers. This makes BizTalk solutions more scalable and tolerant to faults than the run-of-the-mill hub implementations - which is a behavior usually attributed to the bus approach.
Hope this answers your question.
BizTalk is certainly an ESB. EAI is more of a loose concept - BizTalk can certainly be deployed to support EAI, and it can also do a lot more.
BizTalk is more than an ESB but certainly fits the bill. This link is a little old, but answers your exact question.
EDIT: Here is a more-recent MS link that gets into specifics of implementation.
BizTalk can be used as both EAI and ESB.
As for ESB, the BizTalk server architecture is publish-subscribed, a single message can be published to the messagebox which acts as the messaging backbone bus. That message can be received by one or more destination systems that are subscribed to that message. Of course there more capabilities and features that you can get by using BizTalk server like the mapper tool and the use of pipeline components for example.
For use as EAI, BizTalk offers you orchestrations that manage the business logic, LOB(Line of business) adatpers to connect to systems(also legacy), mapper tool, rules engine, and a lot of what you need in order to integrate the different systems in or outside your company.
Absolutely! Biztalk comes from an EIS background, which makes perfect sense for ESB as an infrastructure backplane for service-oriented architectures that span hybrid technical platforms.
At a previous company we chose Biztalk in preference to the IBM ESB product for reasons of functionality and lower cost.
It is Microsoft, so you get what you pay for, but still well worth looking into.
Biztalk Server withot "ESB Toolkit" Is not an ESB.
Because of the following:
Is a contract first, need to build you message types first.
Need to Plan the whole scenario first to minimize the impact of changes.
Changes requires Deployment which increases downtime.
Regarding to your qustion, Yes BizTalk Server is EAI Product
I agree with most of what's said here. It's a stretch to pitch BizTalk as an all inclusive EBS solution even with the EBS toolkit.
To address a couple points made here ...
•BTS is more suited toward asynchronous processes than synchronous
processes - latencies will vary depending on load on the system,
throttling state, etc.
BizTalk hosts with unchanged defaults are not ideal for a low latency. But those hosts are meant to be tuned. Out of the box configuration is not suitable for any situation where throughput is needed. In my experiences of walking into an organization where BizTalk has been shunned there is always an untuned single host setup sitting in the middle of it. It is somewhat analogous to making tables in a dbms with no indexes, getting performance issues and saying the dbms itself sucks.
•BTS is cumbersome when it comes to ease of versioning of services and
schemas (new deployment is needed)
Like with any development platform you need to have a deployment strategy. If schemas have version in the namespace you do not need to redeploy anything. A new version maybe deployed without taking anything down.
As far as the service endpoints are concerned BizTalk can host web services without the use of IIS (BizTalk can use HTTP.SYS to host just as IIS does). To host an inprocess service in BizTalk is merely a matter of importing a binding which can be done without stopping anything in BizTalk. In those end points you can implement versioning as well (like http:.../thing/v1, http:.../thing/v2, etc.).
Anyway ~5 years have passed I'm sure you have hit a conclusion before now :)
BizTalk can do both ESB and EAI, depends how you design your biztalk applications.
I'd like to better understand the reasons for .NET's application server model compared to that used by most Java application servers.
In most cases I've seen with ASP.NET web applications, business logic is hosted in the web server's asp.net hosts processes. Another common approach is to have a physically or logically different tier which hosts your business objects and then are exposed as web services or accessed via mechanisms like WCF. The latter approach typically but not always seems to be used when higher scale is required. In the days of COM objects I've seen Microsoft Transaction Server (MTS) and later COM+ hosting used to host COM objects containing business logic, with MTS (theoretically) managing object lifetime, transactions, concurrency yada yada. This model largely seems to have disappeared in ASP.NET land.
In the Java world you might have Apache with Tomcat as the servlet container and your business objects hosted in Tomcat. In this case, Tomcat provides similar functionality to what MTS provided in the .NET world.
Several questions:
Why the fundamental difference in the Microsoft vs. Java approaches to application servers? This must have been an architecture/design choice when these frameworks were created.
What are the pros and cons of each approach?
Why did Microsoft move away from the MTS-hosting model (which is similar to the Tomcast servlet hosting model) to the more common current approach which is just to have business objects as part of the web server's ASP.NET process?
If you wanted to implement the MTS type approach or the Tomcat type approach in ASP.NET applications today I assume a common pattern would be to host business objects in some IIS process (possibly on some different physical or logical tier) and access via WCF (or standard asmx web services, whatever). Is this a correct assumption?
To my way of thinking, the primary difference is in the "open" approach vs. the "integrated stack" approach. Microsoft likes to provide everything as an integrated stack that all shares a common flavor and approach. Java is more friendly to the "bring your own x" model, where you may want to plug in your favorite application server, transaction manager, etc. Both technology stacks allow in-process invocation as well as remote invocation with varying levels of transaction support.
Really, WCF is not a new technology stack, but a reorganization and rebranding of existing elements of the .NET stack. Specifically, WCF took on the functions of .NET Remoting, Web Services, and distributed transactions.
You reference "the more common current approach which is just to have business objects as part of the web server's ASP.NET process." That is only common for non-distributed apps. It is a simple model that works well when all of your objects will reside on the same server. This follows Microsoft's "Scale Out" deployment model. Rather than segregating object tiers across servers, put everything but the database together on the web servers and then incrementally add identical, redundant servers to scale out the web-server layer.
Microsoft has been pushing hard lately on Service Oriented Architecture, which relies more heavily on WCF and remote invocation. This is seen as a key to the cloud strategy that would have people moving parts or all of their applications to flexible resources in the cloud (which MS would like to host with Azure and the like).