Continuuity Loom 0.9.7: Extensible cluster management

Jun 10 2014, 11:12 am

Derek Wood is focused on DevOps at Continuuity where he is building tools to manage and operate the next generation of Big Data applications. Prior to Continuuity, Derek ran large scale distributed systems at Wells Fargo and at Yahoo!, where he was the senior engineering lead for the CORE content personalization platform.

In March, we open sourced Continuuity Loom, a system for templatizing and materializing complex multi-tiered application reference architectures in public or private clouds. It is designed bottom-up to support different facets of your organization - from developers, operations and system administrators to large service providers.

After our first release, we have heard a lot of great things about how people are using Continuuity Loom and have also heard about features that have been missing. After taking in all the feedback, we are excited to announce the next version of Continuuity Loom codenamed Vela. The theme for this release is “Extensibility” as we have been working towards making Continuuity Loom integrate with your standard workflows for provisioning and managing multi-tiered applications, as well as making it easier to extend Continuuity Loom itself to your needs.

Highlights of Loom 0.9.7

  • Ability to register plugins to support surfacing of plugin defined fields for configuring providers and automators

  • Support for finer grained dependencies

  • Cluster life-cycle callback hooks for integrating with external systems like metering, metrics, etc.

  • Extend your cluster capabilities by adding new services to an existing cluster or reconfiguring existing services

  • Smart support for starting, stopping and restarting services with dependencies automatically included during service operations

  • Personalizable UI skins

  • More out-of-box Chef cookbooks including Apache Hive™ recipes and recipes for supporting Kerberos enabled clusters

Detailed overview of Loom 0.9.7 features

Cluster Reconfiguration

How many times have you had to change some configuration setting of a service on a cluster and had to remember to restart the right services in the right order for the change to be effective? The reality is, when making changes in multi-tiered application clusters, there are a lot of things to remember. Wouldn’t it be simpler if you could change the configuration that you want and let the system figure out everything else for you, ensuring the change you just made is active without any hassle? With this release of Continuuity Loom, you don’t have to worry any more about what services need to be restarted. Continuuity Loom automatically figures out service stop and start order based your service dependencies. You can find more information about how this is done here.

Add missing and manage cluster services easily

Let’s take a concrete use-case: let’s say your administrator has configured a template that allows you to create a Hadoop Cluster (HDFS, YARN, HBase, Zookeeper) with Kerberos security enabled. As a new user, you would like to try building a basic cluster with just HDFS and YARN until you are ready to add more. In that case, Continuuity Loom provides an easy way to remove services that you don’t need during creation time and then subsequently add them back to the live cluster with just a few clicks. With this new release, users will now have the ability to stop, start, and restart services without having to worry about what additional or dependent services need to be restarted.

Plugin Registration

In line with our theme of extensibility, we wanted to ensure that developers are able to write custom Automator and Provider plugins. As part of this, plugins now define the fields they require, which get surfaced in the UI and passed to the plugin during task execution. Particularly for Provider plugins, this allows you to provide different options for provisioning clusters. For example, Rackspace requires a username and API key, while Joyent requires a username, key name, and private key file. It is now possible to write your own plugins and describe the specified fields required. With the addition of this feature, you can also write support at the API level for any container (like Docker), OS, or cloud provider. You can learn more about this feature here.

Finer Grained Dependencies

Prior to this release, all service dependencies were applied at all phases of cluster creation. This created unnecessary solution space exploration and execution of dependencies when they didn’t make sense. This release includes a feature called fine grained dependency management for services. This feature allows Continuuity Loom administrators to specify required or optional service dependencies that apply during runtime or install time (applied only when the service is installed and available on the machine). This is specified during service creation so users don’t have to worry about it. It provides granular control over the deployment of services and opens up support for HA Hadoop clusters and secure hadoop clusters, which require external Kerberos Key Distribution Centers (KDCs). You can learn more about this feature here.

Cluster life-cycle callback hooks

Often times, you need the ability to integrate Continuuity Loom with other workflows that exist in your organization. This feature allows the Continuuity Loom administrator to configure a callback class to insert your own custom logic before and after cluster operations. Out of the box, Continuuity Loom provides a HTTP callback implementation for the interface ‘ClusterCallback’. You can use this feature to integrate the cluster life-cycle with monitoring systems, metering systems, and even your favorite chat application to alert when clusters are created, deleted or upon any failed operations. You can learn more about this feature here.

Personalized UI skins

When you install Continuuity Loom on-premise wouldn’t you like the ability to change the color scheme and logo to make it fit well with the other tools in your organization? With this release you will have the ability to change the color, skin and logo of your Continuuity Loom installation.

This has been an exciting release for us. Check out the Release Notes for more details about this release. Give it a spin by downloading the standalone version for your laptop and visiting the quickstart guide to spin up clusters in cloud.

Help us make Continuuity Loom better by contributing and please report any issues, bugs, or ideas.

Coming soon - Continuuity Loom for free in the Cloud

Be sure to sign up at to be among the first to know when the free, cloud-based version of Continuuity Loom is available.


Continuuity & AT&T Labs to Open Source Real-Time Data Processing Framework

Jun 3 2014, 10:32 am

Nitin Motgi is Co-founder of Continuuity, where he leads engineering. Prior to Continuuity, Nitin was at Yahoo! working on a large-scale content optimization system externally known as C.O.R.E. He previously held senior engineering roles at Altera and FedEx.

Today we announced an exciting collaborative effort with AT&T Labs that will facilitate the integration of Continuuity BigFlow, our distributed framework for building durable high-throughput real-time data processing applications, with AT&T’s streaming analytics tool, an extremely fast, low-latency streaming analytics database originally built out of the necessity for managing its network at scale. The outcome of this joint endeavor is to make a new project, codenamed jetStream, available to the market as an Apache-licensed open source project with general availability in the third quarter of 2014.

Why are we combining our technologies?

We decided to bring together the complementary functionality of BigFlow and AT&T’s streaming analytics tool to create a unified real-time framework that combines in-memory stream processing with model-based event processing including direct integration for a variety of existing data systems like Apache HBase™ and HDFS. By combining AT&T’s low-latency and declarative language support with BigFlow’s durable, high-throughput computing capabilities and procedural language support, jetStream provides developers with a new way to take in and store vast quantities of data, build massively scalable applications, and update your applications in real-time as new data is ingested.

Moving to real-time data applications

When you look at the wealth of data being generated and processed, and the opportunity within that data, giving more organizations the ability to make informed, real-time decisions with data is critical. We believe that the next commercial opportunity in big data is moving beyond ad-hoc, batch analysis to a real-time model where applications serve relevant data continuously to business users and consumers.

Open sourcing jetStream and making it available within Continuuity Reactor will enable enterprises and developers to create a wide range of big data analytics and streaming applications that address a broad set of business use cases. Examples of these include network intrusion detection and network analytics, real-time analysis for spam filtering, social media market analysis, location analytics, and real-time recommendation engines that match relevant content to the right users at the right time.

New developer features

By using jetStream, developers will be able to do the following:

  • Direct integration of real-time data ingestion and processing applications with Hadoop and HBase and utilization of YARN for deployment and resource management

  • Framework-level correctness, fault tolerance guarantees, and application logic scalability that reduces friction, errors, and bugs during development

  • A transaction engine that provides delivery, isolation and consistency guarantees that enable exactly-once processing semantics

  • Scalability without increased operational cost of building and maintaining applications

  • Develop pipelines that combine in-memory continuous query semantics with persistent, procedural event processing with simple Java APIs

For more information, please visit


HBaseCon: Moving Beyond the Core to Address Availability & Usability

May 19 2014, 12:58 pm

Jonathan Gray, CEO & Co-founder of Continuuity, is an entrepreneur and software engineer with a background in open source and data. Prior to Continuuity, he was at Facebook working on projects like Facebook Messages. At startup Streamy, Jonathan was an early adopter of Hadoop and HBase committer.

We just wrapped HBaseCon 2014, the annual event for Apache HBase™ contributors, developers, and users. As in years past, this is one of the most technical conferences that we attend, and it’s really focused on the core community of developers who are doing something meaningful with the enabling technology. What makes HBaseCon so compelling is that it’s not theoretical but rather all about overcoming real technical challenges and actual business use cases. And this year, we noticed a couple of key trends that are shaping the future of HBase.

Overall, we noticed that the HBase discussion has moved up a level, and this is a good thing. We’re no longer talking about the core architecture of HBase, which is pretty much set at this point. So people aren’t talking about doing the architecture better, but instead it’s all about building above what’s already there. Last year was very focused on improvements to the core platform, such as detecting server failure more quickly and recovering, and describing new use cases launching on HBase. But, in the year since, HBase has further stabilized into a mature platform and the new use cases are now established production systems. Now the conversation is around building above HBase and around it for higher availability and usability.

There was a lot of good discussion of increasing availability from an HBase standpoint. In the Facebook keynote on HydraBase, they discussed using a consensus protocol for HBase reads and writes in order to tolerate individual server failures without sacrificing availability or strong consistency. Similarly, Hortonworks and others shared work they’ve been doing on timeline consistent read replicas. For example, if a single server goes down you can still read data consistently up to a given point in time—the most updated snapshot of the data. Google’s Bigtable team also touched on availability by addressing their approach to the long tail of latency.

Multiple approaches to availability are happening, but they ultimately lead to the same goals of trying to reduce the big latency outliers and getting to 5-9s (i.e., 99.999%) reliability. In addition to early adopters like Facebook, Cloudera, and Hortonworks, we’re also encouraged to see a lot of other real users step up and take an active role in the community—we’ve seen this particularly in contributions from Salesforce, Xiaomi, and Bloomberg.

All of these companies are using HBase at very large scale, contributing to its development to continue to move it forward, and then sharing their successes with others. For us at Continuuity, HBase usability is what we’re driving at, and we’ll remain very focused on improving usability so that more developers can build their own HBase and Hadoop applications. This is where HBase is going, and we’re excited to be a part of this community and contribute to its success.


Running Presto over Apache Twill

Apr 3 2014, 11:35 am

Alvin Wang is a software engineer at Continuuity where he is building software fueling the next generation of Big Data applications. Prior to Continuuity, Alvin developed real-time processing systems at Electronic Arts and completed engineering internships at Facebook, AppliedMicro, and Cisco Systems.

We open-sourced Apache Twill with the goal of enabling developers to easily harness the power of YARN using a simple programming framework and reusable components for building distributed applications. Twill hides the complexity of YARN with a programming model that is similar to running threads. Instead of writing boilerplate code again and again for every application you write, Twill provides a simple and intuitive API for building an application over YARN.

Twill makes it super simple to integrate new technologies to run within YARN. A great example of this is Presto, an ad-hoc query framework, and in this blog, I’ll explain what it is and how we were able to make Presto run within YARN using Twill in a short period of time.

Why did we want to run Presto over Twill?

We wanted to add ad-hoc query capabilities to our flagship product, Continuuity Reactor. We looked at different frameworks and got started on experimentation with Presto because it is written in Java and is emerging as an important big data tool. The next question was how to integrate it? We opted to run Presto within YARN because it gives developers the flexibility to manage and monitor resources efficiently within a Hadoop cluster, and the capability to run multiple Presto instances.

We use Twill extensively in Reactor for running all services within YARN. So, in order for us to run Presto within Reactor, we had to integrate it with Twill.

What is Presto?

Presto is a distributed SQL query engine for running interactive analytic queries against data sources of all sizes ranging from gigabytes to petabytes. Last fall, Facebook open-sourced Presto, giving the world a viable, faster alternative to Hive, the data warehousing framework for Hadoop. Presto was designed for interactive analytics and approaches the speed of commercial data warehouses while scaling to the size of large organizations.

How does Presto work?

When executing a query, the query is sent to the coordinator through the command-line interface. The coordinator distributes the workload across workers. Each worker reads and processes data for their portion of the input. The results are then sent from the workers back to the coordinator, which would then aggregate the results to form a full response to the query. Presto works much faster than Hive because it doesn’t need to run a new MapReduce job for every query, as the workers can be left running even when there aren’t any active queries.

How did we integrate Presto with Twill?

First, we needed to run Presto services (discovery, coordinator, and worker) embedded in TwillRunnables, which posed a couple of challenges:

  • The public Presto distribution provides Bash scripts and Python scripts for running Presto services, but has no documented way to run in embedded mode.
  • Presto services normally use external configuration files for various properties like discovery URI and HTTP binding port.
  • Presto on Twill needed to handle varying discovery URIs since YARN cannot guarantee that the discovery service would run on a particular host since any host could become unavailable.
  • So, we configured the Presto services programmatically:

    Bootstrap app = new Bootstrap(;
       app.setRequiredConfigurationProperty("coordinator", "true");
       app.setRequiredConfigurationProperty("datasources", "jmx");
       app.setRequiredConfigurationProperty("discovery-server.enabled", "false");
       app.setRequiredConfigurationProperty("http-server.http.port", propHttpServerPort);
       app.setRequiredConfigurationProperty("discovery.uri", propDiscoveryUri);

    Next, we needed to get Presto services to use an existing Hive metastore with the Hive connector so that Presto CLI can run queries against Hive tables. While Presto includes basic documentation for file-based configuration of the Hive connector, there isn’t any documentation on how to do it programmatically. To tackle this, we inspected the code that loads the Hive connectors. We found that ConnectorManager.createConnection() was setting up the connectors, but the ConnectorManager instance was a private field in CatalogManager, so we had to use reflection. While not ideal, it worked. In the future, we may contribute our source code to Presto to make it easier to embed in Java. The code we used to register the Hive connector is shown below:

    injector.getInstance(PluginManager.class).installPlugin(new HiveHadoop2Plugin());
          CatalogManager catalogManager = injector.getInstance(CatalogManager.class);
          Field connectorManagerField = CatalogManager.class.getDeclaredField("connectorManager");
          ConnectorManager connectorManager = (ConnectorManager) connectorManagerField.get(catalogManager);
          connectorManager.createConnection("hive", "hive-hadoop2", ImmutableMap.builder()
            .put("hive.metastore.uri", propHiveMetastoreUri)

    Once we were able to run embedded Presto without Twill, we packaged Presto with all the dependency jars into a bundle jar file to avoid dependency conflicts. Then we simply configured a Twill application to run various instances of BundledJarRunnable that were running the Presto services contained within the jar file. Below is a full example of a Twill application that runs Presto’s discovery service that is packaged within a jar file using BundledJarRunnable:

    public class PrestoApplication implements TwillApplication {
      public static final String JAR_NAME = "presto-wrapper.jar";
      public static final File JAR_FILE = new File("presto-wrapper-1.0-SNAPSHOT.jar");
      public TwillSpecification configure() {
        return TwillSpecification.Builder.with()
          .add("Discovery", new BundledJarRunnable())
          .withLocalFiles().add(JAR_NAME, JAR_FILE.toURI(), false).apply()
      public static void main(String[] args) {
        if (args.length ");
        String zkStr = args[0];
        final TwillRunnerService twillRunner =
          new YarnTwillRunnerService(
            new YarnConfiguration(), zkStr);
        // configure BundledJarRunnable
        BundledJarRunner.Arguments discoveryArgs = new BundledJarRunner.Arguments.Builder()
            .setMainArgs(new String[] { "--port", "8411" })
        // run Twill application
        final TwillController controller = twillRunner.prepare(new PrestoApplication())
            .withArguments("Discovery", discoveryArgs.toArray())
            .addLogHandler(new PrinterLogHandler(new PrintWriter(System.out, true)))
        Runtime.getRuntime().addShutdownHook(new Thread() {
          public void run() {
        try {
        } catch (InterruptedException e) {
        } catch (ExecutionException e) {

    As you can see, once you have your application running from Java code, Twill makes it straightforward to write a Twill application that runs your code inside a YARN container.

    Adding new features to Twill

    During the process of getting Presto to run over Twill, we contributed a couple of new features to Twill to make it easier for anyone to implement applications that have similar needs: We’ve added support for running Twill runnables within a clean classloader and we’re currently working on allowing users to deploy Twill runnables on unique hosts. In the future, we plan to open-source our Presto work so that anyone can spin up their own Presto services in YARN, and we are also considering support for Presto in Reactor to speed up ad-hoc queries.

    Apache Twill is undergoing incubation at the Apache Software Foundation. Help us make it better by becoming a contributor.

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    Introducing Continuuity Loom: Modern Cluster Management

    Mar 20 2014, 11:28 am

    Jonathan Gray, CEO & Co-founder of Continuuity, is an entrepreneur and software engineer with a background in open source and data. Prior to Continuuity, he was at Facebook working on projects like Facebook Messages. At startup Streamy, Jonathan was an early adopter of Hadoop and HBase committer.

    Our flagship platform, Continuuity Reactor, utilizes several technologies within the Apache HadoopTM ecosystem, so as we started building it, our developers needed an easy way to test Reactor on real distributed systems. They needed a fast, self-service way to provision clusters, both on our own hardware and in public clouds, because testing against real clusters is such a critical and frequent component of our development cycle. Our vision was to enable all Continuuity developers to be able to quickly create a cluster with the push of a button.

    We started off with simple scripts. But scripts had multiple issues - they required a lot of setup, there was no central management keeping track of available clusters, and the scripts had to be changed whenever we moved from one cloud to another, or one software deployment to another. Next, we started looking at different SCM (software configuration management) technologies and picked Chef. Combining scripts and Chef recipes, we’re able to get to one-button push, but it became extremely complex for two reasons - there were an increasing number of customizations needed for each new type of cluster and a significant amount of setup was needed on every developer’s box.

    When we launched Reactor, we wanted to enable developers to deploy our single-node Sandbox Reactor to a public cloud directly from the website. This forced us to think harder about designing a complete production system while still providing an easy and flexible solution for our developers. We wrote a combination of scripts and Chef recipes, designed a system that can templatize the Hadoop cluster, added capabilities to make it extendable to other services and providers, and made it very developer and ops friendly - that’s when Loom was born.

    Today, Loom is used to provision Sandbox Reactors on the Continuuity Cloud and as an internal DevOps tool to test new and incremental features on an ongoing basis. We’ve been developing and using Loom for almost a year and we’re noticing the benefits: our developer and DevOps productivity has doubled, and our development and test cycles have become faster.

    We built Loom for ourselves. But today, we’re open sourcing it for anyone to use because we believe that the broader developer community can benefit from it.

    What is Continuuity Loom?

    Continuuity Loom is cluster management software that provisions, manages, and scales clusters on public clouds and private clouds. Clusters created with Loom utilize templates of any hardware and software stack, from simple standalone LAMP-stack servers and traditional application servers like JBoss to full Apache Hadoop clusters comprised of thousands of nodes. Clusters can be deployed across many cloud providers (Rackspace, Joyent, etc.) and virtualization platforms (like OpenStack) while utilizing common SCM tools (Chef, scripts, etc.).

    Loom from Your Laptop

    Developers can use Loom to provision and decommission a cluster directly from their laptop. Loom creates a very simple user API that allows the developer to choose the type of cluster, how many nodes, and which cloud. Any developer can go from zero to Hadoop, from their laptop to any cloud, in minutes.

    Worry-Free Provisioning

    Loom simplifies the installation and configuration of any software stack, including Hadoop, and ensures that all installations are verified before a cluster is made available. Developers can create custom cluster types ranging from single VM application servers to large-scale, distributed, heterogeneous clusters.

    Download Loom for Free

    As a developer, building Big Data applications using Continuuity Reactor is just one part of the equation. The other part involves provisioning and managing your Hadoop cluster, and deploying your applications to the Hadoop cluster. With Loom, we’re empowering DevOps in a truly self-service way. Download and run Loom on a Mac laptop (currently experimental), and start or spin up Hadoop clusters and other software stacks across any private or public cloud.

    Open Sourcing Loom

    Loom is a relatively new project but highly extensible in the providers and services that can be supported. Open sourcing Loom allows others to add support for new software stacks, currently unsupported recipes/scripts, and new infrastructure/provisioning systems. Help us make Loom better by contributing here and please report any issues, bugs, or ideas.

    Loom for the Enterprise

    In many companies, developers must submit requests to individuals in other parts of the organization to obtain a Hadoop cluster or to run distributed software on a group of machines. This process can be incredibly slow and burdensome for both the developer and IT, decreasing developer productivity and increasing IT overhead. With Loom, the IT department can codify reference architectures and maintain a centrally controlled catalog of cluster templates that can be provisioned directly by developers. IT administrators then use a centralized dashboard to monitor and manage multiple clusters concurrently across multiple clouds.

    Download Loom to start managing and provisioning your own clusters today, or contact sales if you need enterprise support for Loom.

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