I need to deploy two node services to CF (each service in its own container).
The apps need to communicate. How is it recommended to implement this communication? I can't find any guide which explains service-to-service communication in CF, and since it should deploy to the cloud I need some best practices. Some examples will be very helpful.
This is a classic question that always come to solve any enterprise application integration pattern and it comes down to the point that, what type of integration needs one has.
If an app want to have synchronous communication to get a real time response, RESTFul APIs are the most loved integration style of this age. But one also need to consider that, creation of huge numbers of APIs (which is the downside of going with Microservices based architecture) also brings-in the huge overhead of maintaining the set and locating the correct one. An API Gateway and a Service Discovery tools should be of help here. I am a novice about Blue-mix but you can surely host a Spring-Cloud-Eureka or Consul based Service Discovery on it to serve the purpose, and similarly Spring Cloud Zuul to have an API Gateway.
Another simple catch here is to ensure not to build one central service as fat spof to cater to whole of your microservices world but rather have many such services each catering to a contextually bound microservices.
On the similar line, if the need is to have async communication, message brokers such as - RabbitMQ, Kakfa should be the best and simplest integration style for apps to communicate. The same catch of not building a SPOF service but rather have separate service instances one each for a set of bounded microservices applies here as well, with all these instances being further federated for wider communication should be taken care of.
Your answer will depend on what kind of communication you want between your apps.
If you're looking to deploy a microservice-based architecture pattern for your Node services, i.e. server code that performs an independent, granular business function, I would recommend getting started reading the docs here and using the new Bluemix Developer Console.
Here there is a growing set of patterns and starters that you can use to understand and develop cloud native apps that can communicate to each other by exposing API endpoints compliant with the Open API specification and auto-generating SDKs for your omnichannel client applications.
After downloading the selected starter, you can modify the code to expose an API that performs the business logic that you need. Subsequently, you can run your project locally in a container or deploy it to Bluemix using the bx dev command line tool.
After setting that up, you will have cross platform, language independent communication between your microservices and client applications.
Related
I am using Azure Table storage to store the data of my application. I need to build an API to retrieve the data from Azure table storage. There are like a million records in the table. In the initial stage, my API would be getting approximately 100-1000 hits per day. What would be the best choice to develop that API on, API apps or Service Fabric?
It depends on a lot of aspects:
How do you want to maintain it?
What performance requirements do you have? Do all those 100-1000 hits per day happen at the same time or are they distributed across the day?
How do you want to handle scaling?
As described by #feranto the main difference is the architectural pattern. The decision will have a lot of implications for you, not only when it comes to development, but you will have to consider how to maintain your application.
Only based on your short description, it sounds like a relatively straightforward solution and not very complex nor very high performance/scale requirements. Given that, it might be easier for you to go for a more basic API App. Service Fabric is an excellent framework and architecture that allows us to build very flexible, highly scalable solutions, but it should be noted that that also comes with a lot more complexity when it comes to handling, monitoring and maintaining both the underlying service cluster and it's applications.
Setting up an API App, connecting to an Azure Storage table and control that with for instance Application Insights is relatively straight forward and you can find a lot of documentation and samples for that. As a contrast, Service Fabric is fairly nascent in documentation and samples, and you would have to read up on a lot to get a basic stable solution running if you are new to it.
The main difference between Azure API and Azure Service Fabric is the architecture pattern each one follows:
Azure API APPs supports a monolithic architecture. You have all your code running as one single package. You can develop this using Java, PHP, nodejs, python or .net.
Service Fabric follows a microservice architecture. Every service is deployed on a separate node, which can scale independently, and you can monitor the health of every service in every node. You can develop this using Java or C# mainly.
Here you can see advantages and disadvantages between microservices and a monolithic architecture.
Background
Having run through the Getting started with API Apps and ASP.NET in Azure App Service tutorial (https://azure.microsoft.com/en-gb/documentation/articles/app-service-api-dotnet-get-started/), we had an architecture question arise today around the design decisions made to split out the To Do List Application API layers into a Middle tier API app and Data tier API app.
When approaching build of an application using a distributed architecture, what considerations should take place to understand when this type of separation should occur in your API layers?
Another way of asking this question is what are the pros and cons of having a separate middle tier API layer and data tier API app when building your application?
Other Questions
I had a read of Web apps architecture: 1 or n API question (see link that follows) which while being insightful, was slightly different to the question we are asking. We are talking a single domain which has separate API layers for middle tier (logic) and the data tier.
Web apps architecture: 1 or n API
This of course, depends. Deciding whether to build out what I call "infrastructure services" is very strongly dependent on your needs and your application(s).
Infrastructure tier services generally get much more re-use than business logic tier services. They are very easy to recompose into new applications. The most common instance of this is building an admin interface as a separate application.
If you have already build several applications in your organization, and have found reuse to be occurring regularly, then I would seriously contemplate infrastructure services. If your organization is writing it's first application, and you don't see this fanning out to additional interfaces, then maybe just isolate your data access in a DAO pattern, it's fairly straightforward to refactor it out to a stand-alone service later.
I think the example design is somewhat confusing. In real world, I have not seen such design yet because design looks like having every function to be http/rpc call?
My experience would be the SPA uses a Public API (or Gateway API) which then calls your Internal API / Microservices to aggregate results. It is your Microservices that may have DAOs and, most importantly, the business logic
Service Fabric was just announced at the build conference. I was reading the scarce documentation about it and I have a question.
I'm evaluating Service Fabric for hosting CRUD like microservices that are at the moment built in ASP.NET WebApi.
Is Service Fabric geared towards hosting small pieces of functionality that receive data, process it and return the result, rather than hosting CRUD WebApi types of application?
Service Fabric enables the creation of both stateless and stateful microservices.
As the name suggests, any state maintained by an an instance of a stateless service will be lost if the node goes down. A new, fresh instance will simply be spun up elsewhere in the cluster.
Stateful services offer the ability to persist state without relying on an external store. Any data stored in a Reliable Collection will be automatically replicated across multiple nodes in the cluster, ensuring that the state is resilient to failures.
A common pattern is to use a stateless service as the client-facing gateway to the application and then have that service direct traffic to the app's partitioned stateful services. This hides the work of resolving partitions from clients, allowing them to to target one logical endpoint with all requests.
Take a look at the WordCount sample for an example of how this works. The WordCount.WebService stateless service acts as the front end to the application. It simply resolves the partition based on the incoming request and then sends it on. The WordCount.Service stateful service (partitioned based on the first letter of the word) immediately puts those incoming requests in a ReliableQueue and then processes them in the background, storing the results in a ReliableDictionary.
For more details, see the Reliable Services Overview.
Note: for now, the best way to expose WebAPI endpoints to clients is to self-host an OWIN server in the stateless service. ASP.NET 5 projects will soon be supported as well.
This video answers my own question: http://channel9.msdn.com/Events/Build/2015/2-704. In summary, we should use Stateless Services to host ASP.NET based sites or API's which persist data to external data stores.
If you don't have state (or have it externally), Stateless Service is the way to start.
Answer to the original question is "both". Basically, anything that have main() function (with couple of more extended contract methods to talk to Service Fabric) can be a service in Service Fabric world.
I'm building a game for Windows Phone 8 and would like to use Windows Azure SQL Database for storing my users' data (mostly scores and rankings).
I have been reading Azure's documentation on SQL Database and found this link which describes just the scenario I'm looking for (it's Scenario B in the picture): I want my clients (the game running in a user's windows phone) to get data from an SQL Server through a middle application also hosted on Windows Azure.
By reading further the documentation (personally I think it's really messy and hard to find what you're looking for in there), I've learned that I could use Cloud Services for this middle application, however I'm not sure if I should use a background worker which provides an HTTP API or a worker with a Service Bus Relay (I discovered that I can use service bus in WP8 in this link).
I've got a few questions that I couldn't find an answer to:
1) What would be the "standard" way to go in this case?
2) If both ways are acceptable, are there other advantages to using a Service Bus other than an easier way to connect and send messages to my middle application? What are the disadvantages?
3) Is a cloud service really what I'm looking for (and not just a VM with the middle application code running in it)?
Its difficult to answer these sort of question as there are lots of considerations. I don't believe there is a necessarily 'standard way'.
The Service Bus' relay service's purpose is to help traverse firewalls and NATs, not something that directly relates to your scenario, I suspect.
The Service Bus, though, also includes a messaging capability which provides queues, topics and subscriptions to use to exchange messages between clients or client/server.
You could use the phone client to write and read messages to/from queues. you would then have a worker role hosting your application logic and accessing the database as needed.
Some of the advantages of using messaging include being load leveller, helping handling peaks in traffic (at the expense of latency), helping separating concerns and allowing you to accept requests from the clients when the backend is down as so can help with resiliency.
In theory they can also help you deliver messages to the client in the same fashion, by using a queue or subscription per client, but for a large number of clients this may become a management issue.
On the downside you would have to work with what is a proprietary protocol, and will need to understand the characteristics and limitations of the service bus. you will need to manage the queues and topics over time. there will also be some increased latency, although typically not an issue and, finally, you will have to implement asynchronous messaging on the client side which has advantages but is also harder to implement.
I would imagine that many architectures follow the WEB API route by using a web role cloud service exposing the API. The web role can then perform any business logic and connect to the database in the background.
A third option, which you didn't mention, is to use Windows Azure Mobile Services and implement your business logic as a service API there
I am having a hard time understanding Windows Azure service bus and access control concepts. In layman's terms, what are they? What are they used for?
The Service Bus component of Windows Azure is meant to handle the problems arising from services that are living in multiple networks. Basically, a service bus just makes it appear as if your code is running on a single machine, while in reality it could be running anywhere within the Azure datacenters.
Access Control lets you use "federated authentication for your service based on a claim-based RESTful model. (Sorry, copy&Paste from an O'Reilly book about Azure!)
Basically, when you create an Azure site, application or service, it could be running on any of the thousands of systems within the datacenter. And each of those systems has it's own IP address, it's own network, memory, processor and whatever more. To let them collaborate and to appear as a single system, these two services have been created.
If you want to learn more about Azure, this would be a good moment to buy a book! :-)
Azure is quite complex and service buses and access control are a bit more advanced topics.
Service Bus is a solution for the integration between multiple applications whether they are hosted on the same infrastructure or even spread along multiple infrastructure or/and Cloud Computing provider. If you search more in the internet you might find a lot about EAI (Enterprise application integration) here is my blog post about this topic:
http://hhaggan.wordpress.com/2013/03/07/introduction-to-enterprise-application-integration-eai/
and here another that I hope that helps you understand better what is the service bus:
http://hhaggan.wordpress.com/2013/03/09/introducing-service-bus/
in another words, it is a messaging platform that helps you communicate with multiple applications, softwares or services no matter what programming language they are written with or on which os or platform they are hosted on. you will feel its effect specially when you work on connecting multiple nodes together, I don't mean 5 or 6 nodes but 10 and above.
Certainly there are several types of service bus, whether they are based on relayed messaging service or brokered messaging service, each one of them has several uses, its purpose and way of working.
For the Access control, this is so easy, it is a way of authentication and authorization for your application using third parties, It is a claim based identity that you can do the required authentication through the third party database. you wont need to build everything from scratch in your database. this helps a lot during development and I believe that this can help a lot in social media marketing and branding because of the use of facebook, twitter during the authentication.