Don't ignore the 'Core' in Continuous Delivery

You see, I'm a person who loves to write code, travel around the world, take nice pictures and eat!!! But nothing less than that, I also enjoy running (especially in the morning!!!, ). It's amazing to have that feeling of the fresh air, smell of the grass and sense the muscles working while observing the surroundings. My running helps me to do my job better because it helps clear my mind, relieves stress and builds a lot of confidence. Its provides me with those moments with great ideas and solutions to most of the problems you have at work or life. By the time you finish running, you have already set up the goal for the day with a certain amount of clarity about the activities that you have to do.

The more I started running, the more I loved challenging myself with those extra miles and pace. But with my overgrowing excitement, I was making the obvious mistake.. I was running too much, too soon, too fast. While doing so, I forgot about the "little things" that help stay healthy and flexible. I started getting injuries, my hips and hamstrings were always tight. I was breaking down with back pain and injuries. I knew I was doing something wrong and it was time to get an expert advice. Having heard the back pain story many times, the physio explained me about the importance of 'Core' muscles and the exercises to do that would strengthen my muscles and improve my core stability. He suggested doing squats, swimming, pull ups, crunches etc. So I decided to give my running a break and focus on core building. It felt a bit off in the gym doing all those non equipment exercises while everyone else was lifting those 20/30 kg dumbbells, but a month after training, I started noticing the difference. I felt more stronger with increased muscle mass, my posture was better, lost some body fat and I was more agile!!! I started running again and this time I noticed the difference immediately. My core helped me to maintain an efficient running form  helping with better stability, balance, posture and overall control.

In short, lesson learnt from my running experience. "Ignoring core strength in your training program may look like working for a short term, but is a recipe for long-term disaster. Lack of core-strength and flexibility causes your body to find a path of resistance towards running or cause the body to adapt in a negative fashion that will most likely lead to complex injuries!!!"

Well how does this relate to continuous delivery and DevOps? The answer is , before immediately adopting a CD tool and start working on the pipeline, you should prepare the teams and the organization with the core of continuous delivery. The core practices like version control, build automation, test automation and continuous integration increases software process agility and helps create an organizational culture and structure to fully embrace CD.

In this post, I’ll describe some of the core practices of continuous delivery  that helps delivering software feature more frequently and reliably. 

Version control everything

Putting everything in version control (source code, build scripts, test scripts and data setup, monitoring scripts etc.) This helps in keeping track and control everything. Keeping track of the changes gives the flexibility of undo or replay any changes easily in all environments including production. You can also understand who made a change and why. Version controlling also creates the first level of built-in safety net, preventing any out of process, locally made changes or manual overrides from entering the production environment. Every change a developer makes must in the source control, any failure to do so will be overridden in the next deployment if not present in the source control.

Practice TDD

TDD is a software development approach where the development of code is driven by first writing an automated test case, followed by writing the code to fulfill the test and then refactoring. With continuous delivery, it’s very important to have the tests pushed into source control along with the implementation code. This helps in ensuring that every new code pushed will be tested in the same build process. This eliminates the risk of delivering to production the code that does not meet quality requirements.

These automated tests helps identify errors in a really short period of time. These tests give developers very fast feedback when something breaks. These tests are also called change detectors. When you make a change, the tests will detect very soon if there are any problems or mistakes. With continuous delivery organizations need the have the ability to make frequent releases of their software without the risk of breaking existing features or adding new bugs. The success of the business depends on how fast it can react to changing environments and address the new improvement suggestions with assurance. Test-driven development is the methodology that makes such flexibility, maintainability, and extensibility possible.

Continuous integration

"Continuous Integration is a software development practice where members of a team integrate their work frequently, usually each person integrates at least daily - leading to multiple integrations per day. Each integration is verified by an automated build (including test) to detect integration errors as quickly as possible. Many teams find that this approach leads to significantly reduced integration problems and allows a team to develop cohesive software more rapidly." - Martin Fowler

Continuous integration process runs ensures that the tests are executed every time a change is pushed into source control and ensures that the new changes didn’t break any other parts of the software. Every push automatically triggers multiple tests. Then if one fails it’s much easier to identify where the error is and start working to fix it.

Automate everything

Automation is the heart of every successful continuous delivery transformation process and the single biggest enabler for CD. The success of continuous delivery lies in stable environments, consistent build and test process and happy releases. Automation can be used to make the release process more deterministic and to bridge the gap between development and production. Development teams can learn from operations the value of automation and how to create automation scripts to improve the overall process. Together the team is responsible for defining the desired state of the infrastructure and convert this to code. The degree to which your organization can achieve successful one click deployment process that can be initiated by anyone whenever needed depends on the level of automation at every stage. At the processes like code analysis, testing, environment provisioning, defect detection and prevention at all stages should be automated. Any manual tasks should be treated as technical debt and later picked up as part of the sprint and addressed.

Test automation

The key to building quality into our software is making sure we can get fast feedback on the impact of changes. Test automation can automate some repetitive but necessary tasks in a formalized testing process already in place, or perform additional testing that would be difficult to do manually. Companies adopting continuous delivery should ensure that when issues are identified they can be managed and resolved quickly and definitively. The easiest and effective way to achieve this is by having an automated test suite incorporated in the release pipeline and CI process. This kind of a process where automated regression, performance and security tests are constantly executed as part of the deployment strategy helps identify issues early and deal with them before they reach the later stages of the deployment cycle/pipeline.

Monitor and measure everything

Proper and effective monitoring of the entire process and environments is important to provide crucial information that ensure service uptime and optimal performance. It's important to measure the progress of the approach to know whether teams are improving or making progress. With the support of proper data and metrics, it’s easy for teams to inspect the current way of working and come up with ideas or processes to improve the overall CD/ DevOps movement. Measuring the current capabilities and process helps teams determine the problem areas and defined focus points for making a change.

An important DevOps practice is to work with application monitoring and insights to enable full end-to-end traceability in a product to provide both operational insights and  usage understanding

Keep focus on these core practices and move forward with your continuous delivery journey!!!

“….to satisfy the customer through early and continuous delivery of valuable software” - #1 of the twelve principles behind the agile manifesto.

Why automated end to end tests may not solve your quality issues

Our customer asked us to help us with an approach for end to end testing. The problem the teams were facing was mainly due to the errors detected during the integration phase/ environment where end to end tests were executed. During the discussions with the teams we noticed that the organizing of teams was based on loosely coupled software components. The teams worked on individual components that were versioned, tested and deployed independently. They had development or test environments were the system tests were executed as part of the build or release process. These system tests were executed against the stubs of the dependent components and verified successfully.

The teams used to get requirements per component which did not specify the entire use case, most of them were in the format of “if a message in format XYZ is given to the component, then do something and send the output to another component in the system in a different format.” Each team developed these user stories and delivered the stories with tests to ensure that the components worked fine, given the correct data is provided in the expected format.

But there was no guarantee that the whole system was working as expected. Most of the time, there were integration issues, due of the wrong versions of components in an integration environments or schema mismatches etc. Different component teams worked in isolation and failed to communicate about the recent releases to other teams. This introduced the need of a separate team to test the system as a whole. The responsibility of this team was to create end to end tests to check and ensure whether the whole system worked properly with multiple components deployed.

The end to end tests now helps in identifying  integration issues before deploying to an higher environment. Only the problem was not completely solved!!!

The issues detected by the integration test team was reported back to the component teams and which was normally not picked up in the current sprint, but has to be put into the backlog for later iterations. This introduced waiting periods and tensions between the different silo teams. Developers were working on parts of the complete applications who were not aware of how the complete system functions were not able to test the system as a whole.

End to end testing was not a solution to this situation, but just a workaround to suppress the problem from getting into higher environments. A better solution will be to organize the teams into feature teams where the team can shift their focus on value delivery and work on business features rather than technical components. Now the teams have acceptance criteria that maps a customer centric use case, rather focusing on a part of the use case. Compared to the component teams, feature teams can provide better design decisions and thus better tests because of the knowledge of the whole application,  technology stack and use cases. The automated tests delivered as part of the user stories now cover the whole feature and not only part of the application.

The feature team as a whole now have the required skills to implement the entire customer centric feature. The integration test team members are also part of the feature teams and assist in ensuring the correct functional tests are captured as part of the development process.

How to create a reliable cluster management system using SQL server for orleans

Orleans runs on a cluster of servers in a data center, each running a container process that creates and hosts actor activation. A service built on Orleans is deployed on a cluster of nodes. When deployed to a cluster of nodes, Orleans internally implements a set of protocols to discover and maintain membership of Orleans silos in the cluster, including detection of node failures and automatic reconfiguration.

Cluster management is supported in Orleans via a built in membership protocol, also referred to as Silo membership. The goal of this protocol is for all silos to agree on the set of currently alive silos, detect failed silos, and allow new silos to join the cluster. For reliable management of cluster membership, Orleans uses Azure Table, SQL Server or Apache ZooKeeper for synchronization of nodes.

This post we’ll see how we can use the SQL server implementation of the membership table and make use of the cluster management feature.

Step 1: Creating the database

Create a new database OrleansMembership in your SQL server and run the below given script to create the required tables and data for SQL server membership provider.

https://github.com/dotnet/orleans/blob/master/src/OrleansProviders/SQLServer/CreateOrleansTables_SqlServer.sql.

Step 2: Configuring the membership setup in the  SystemStore element settings: 

In the silo configuration file (OrleansConfiguration.xml), add a new section SystemStore in the Globals section with the connection string for the OrleansMembership table we created in step 1.

<OrleansConfiguration xmlns="urn:orleans">

  <Globals>

   

    <Liveness LivenessType="SqlServer" />

    <SystemStore SystemStoreType="SqlServer"

                 DeploymentId="OrleansClusterDemo"

                 DataConnectionString="Data Source=.\SQLEXPRESS;Initial Catalog=OrleansMembership;Integrated Security=True;Pooling=False;Max Pool Size=200;Asynchronous Processing=True;MultipleActiveResultSets=True"

                 AdoInvariant="System.Data.SqlClient" />

   

  </Globals>

</OrleansConfiguration>

Step 3: Update the silo projects with the nuget packages for sql client and sql utils:

"Microsoft.Orleans.OrleansSqlUtils": "1.4.0",

"System.Data.SqlClient": "4.3.0"

Step 4: Update the client configuration with the membership table information: 

The client configuration should also be updated with the OrleansMembership table using the SystemStore element.

<ClientConfiguration xmlns="urn:orleans">

  <Tracing DefaultTraceLevel="Info"

           TraceToConsole="true"

           TraceToFile="C:\OrleansLogs\WebApiClient-{0}-{1}.log"

           WriteTraces="false"/>

  <Statistics MetricsTableWriteInterval="300s" PerfCounterWriteInterval="30s" LogWriteInterval="300s" WriteLogStatisticsToTable="true" StatisticsCollectionLevel="Info"/>

  <Messaging ResponseTimeout="30s" ClientSenderBuckets="8192" MaxResendCount="0"/>

  <SystemStore SystemStoreType ="SqlServer"

                 DeploymentId="OrleansClusterDemo"

                 DataConnectionString="Data Source=.\SQLEXPRESS;Initial Catalog=OrleansMembership;Integrated Security=True;Pooling=False;Max Pool Size=200;Asynchronous Processing=True;MultipleActiveResultSets=True" AdoInvariant="System.Data.SqlClient" />

</ClientConfiguration>

Also notice that you don't need to use the ProxyingGateway anymore for the Primary silo address. Instead the client can now use the membership data for grain references.

Conclusion:

We have created a reliable deployment that is configured with membership using SQL server. In this case, all silos are created equal, with no notion of a primary of secondary silos. This is the recommended production deployment scenario where a failure of a single node or a combination of nodes does not affect other silos in the cluster. This also means that you don't need to provide a Seed node option in your silo configuration anymore!!!

How to create a monitoring infrastructure for your Orleans silos and grains

Orleans dashboard is a configuration based bootstrap provider for Orleans silos. The dashboard provides details on the performance of silos, individual grains and also the details on failures etc.

If you are new to actor systems and orleans, it may be helpful to read the official documentation https://dotnet.github.io/orleans/index.html

How do you use it?

First thing you want to do is install the OrleansDashboard packages via NuGet to the GrainServer project (this is where the gains are implemented)

Install-Package OrleansDashboard

Register the dashboard bootstrapper into the Orleans system

In the OrleansConfiguration.xml file add the new bootstrapper. You can mention the port number on which the dashboard will be accessible. The default value is 8080.

<OrleansConfiguration xmlns="urn:orleans">

  <Globals>

    <SeedNode Address="localhost" Port="11111" />

    <StorageProviders>

      <Provider Type="Orleans.StorageProviders.SimpleSQLServerStorage.SimpleSQLServerStorage" Name="SqlStore"

                ConnectionString="Data Source=.\SQLEXPRESS;Database=OrleansStore; Integrated Security=True;"

                UseJsonFormat="false" />

    </StorageProviders>

    <BootstrapProviders>

      <Provider Type="InfraAutomation.GrainServer.BootstrapServer" Name="BootstrapServer" />

      <Provider Type="OrleansDashboard.Dashboard" Name="Dashboard" Port="8081" />

    </BootstrapProviders>

  </Globals>

....

Start the silo and you can now access the dashboard at the configured port like http://localhost:8081

How to integrate ASP.NET WebAPI and Microsoft Orleans

Orleans is a runtime and programming model for building distributed systems, based on the actor model. In an actor based programming model, actors represent multiple instances of related real-world artifacts and interact with each other as independent single threaded entities.

In Orleans the actor is represented as a grain, that contain state can be uniquely identified and expose logic via asynchronous methods. These grains are isolated from one another and can only communicate via messages. These grains are hosted on silos which houses the Orleans runtime, that performs operations like grain instantiation and look-up. Even though these silos can be connected over a network, to make request into a solo, you can create client applications like an ASP.NET WebAPI which uses the GrainClient.GrainFactory to provide remote access. This also helps to perform operations like authentication and authorization on the grain system from the web Api. This also helps to create a service that encapsulates the Orleans system so that clients don’t need to interact with the Orleans clients and do RPC, instead can make use of the RESTful Api and use HTTP for communication.

If you are looking are looking for a sample tutorial on how to create a grain server and host it locally, refer to the sample here: https://dotnet.github.io/orleans/Tutorials/Minimal-Orleans-Application.html

To get started, we have to create a .net core WebAPI project and use this to as the client project to invoke calls to the silos. Follow the steps below to use this API to invoke grain calls.

Adding nuget packages:

In the project.json file add the references to the following nuget packages.

"Microsoft.Orleans.Core": "1.4.0",

"Microsoft.Orleans.OrleansCodeGenerator": "1.4.0",

"Microsoft.Orleans.OrleansCodeGenerator.Build": "1.4.0",

"Microsoft.Orleans.OrleansRuntime": "1.4.0",

Creating the client configuration:

Orleans can be used in a variety of configurations that fit different usage scenarios, such as local single node deployment for development and testing, cluster of servers, multi-instance Azure worker role, etc. All of the different target scenarios are achieved by specifying particular values in the Orleans configuration XML files. The client configuration is used to specify the silos gateway endpoints to connect to. For this sample I am using to connect to the local silo, so we should configure the gateway to localhost. You can also use the Client configuration file to specify the Trace settings etc.

In the WebAPI project create an XML file ClientConfiguration.xml and copy the contents below

<ClientConfiguration xmlns="urn:orleans">

  <Gateway Address="localhost" Port="30000"/>

  <Tracing DefaultTraceLevel="Info"

           TraceToConsole="true"

           TraceToFile="C:\OrleansLogs\WebApiClient-{0}-{1}.log"

           WriteTraces="false"/>

</ClientConfiguration>

Initializing the GrainClient:

The connection to the grain server/ silos are established by initializing a grain client. The GrainClient.Initialize method accepts a client configuration object that will initialize the client using the configuration provided. In the Startup.cs file, use the code below to initialize the GrainClient.

public void StartSiloClient()

{

    var config = ClientConfiguration.LoadFromFile("ClientConfiguration.xml");

    // Attempt to connect a few times to overcome transient failures and to give the silo enough

    // time to start up when starting at the same time as the client (useful when deploying or during development).

    const int initializeAttemptsBeforeFailing = 5;

    var attempt = 0;

    while (true)

    {

        try

        {

            GrainClient.Initialize(config);

            break;

        }

        catch (SiloUnavailableException)

        {

            attempt++;

            if (attempt >= initializeAttemptsBeforeFailing)

            {

                throw;

            }

            Thread.Sleep(TimeSpan.FromSeconds(2));

        }

    }

}

The StartSiloClient can be invoked from the Configure method in the Startup.cs file

The controller:

Now we have initialized the GrainClient, we can make use of the static methods in the GrainFactory to get a reference to a grain and start working.

[HttpGet]

public IActionResult GetAll()

{

    var vm = GrainClient.GrainFactory.GetGrain<IGetAllVirtualMachine>(Guid.NewGuid());

    var result = vm.GetAll().Result;

    if (!result.Any())

    {

        return NoContent();

    }

    return new OkObjectResult(result);

}