|By Zev Laderman||
|August 12, 2005 04:00 PM EDT||
You don't have to be around Linux for long before you hear about "the dependency problem," which is no problem at all for many users - until the day it bites them. In a nutshell, the problem is that most Linux applications depend on the operating system to provide various pieces of functionality that the applications need. These components most often take the form of shared libraries that are dynamically loaded and linked to the application at runtime. Problems occur when one or more of these libraries are replaced with a different (usually newer) version. Provided all the interfaces remain the same and the semantics of the functionality remain the same, there's no problem. However, due to security fixes, bug fixes, or new or improved functionality, the interfaces and semantics can and do change, and the changes can be enough to break the application.
In general, individual libraries aren't distributed individually but as part of a package of related components. Packages are installed as a whole. In general there's no way to take just one part of a package, and in fact to do so would be inviting trouble since packages are usually composed of related components that need to be installed as a whole to guarantee that the components work together correctly.
It would seem reasonable to assume that once an application is installed and working there would be no reason to touch it, or any of the components that it depends on. However, there are myriad reasons why components end up changing. The most common are:
- A new application is installed that requires a later version of a package containing one of the shared libraries used by the first application.
- A security or bug fix affects a package used by the application.
- An update version of the OS from the distributor includes newer packages.
This problem isn't unique to Linux. It's been a long-time problem with many different Unix systems that make heavy use of shared libraries, and is essentially the same as the famous "dll hell" that afflicted older versions of Windows (a Windows .dll file is a dynamically loaded shared library). Unix vendors reduced the problem to manageable proportions by tightly controlling the evolution of the system and providing lots of advance warning to third-party vendors of impending changes. Microsoft adopted similar tactics and became adamant about which libraries third parties were free to change, and which they weren't, making it difficult for third-party applications to overwrite system-provided libraries.
Linux is essentially no better or worse in terms of shared library management than Unix or Windows. What's different is that there's no central coordinating authority to make sure that changes happen in a controlled and consistent manner. In some respects this is one of the strengths of Open Source development; it allows change to happen at its natural pace and forces people to be more aware of the potential problems associated with change. It's also a weakness from the point-of-view of an end user having to integrate systems with components with different dependency requirements.
Linux distributors spend a lot of time and effort making sure that their systems are delivered with the dependencies all correctly resolved, and that any updates they create don't disturb this balance. They often go so far as to take security/bug/performance updates that tend to be created by the component development group on the latest version of their software - which is probably not the version currently shipping - and back-port the changes to the shipping version and test to make sure the changes don't introduce any inconsistencies. However, distributions have limited control over third parties, both commercial and Open-Source, that are reluctant to re-test their products with every new version of a package on which they have a dependency.
One of the interesting benefits Linux holds for its enterprise adopters is that it's multi-sourced. Essentially the same product is available from multiple vendors, improving competition and avoiding lock-in. Although managing multiple Linux distributions adds overhead, some companies prefer not to put all their eggs in one basket and use multiple distributions to help ensure that they don't end up locked in to a specific distribution.
However, this adds a new dimension to the dependency problem.
In many instances, different packages are used on different distributions. There's no standardized system for packaging, although most major Linux distributors use the RPM packaging system that defines how the package is constructed and what information it contains on individual file location and a set of dependency rules. Unfortunately, the same package name on two different distributions can contain different revisions of components or even different components. To add to the problem, not all Linux systems use the same package mechanism. For example, Debian-based systems don't use packages at all.
The end result is that the configuration management of these systems becomes quite complex. Applying something such as a security fix may necessitate other changes to bring the dependencies back into alignment, and then subsequent testing of all applications running on those revised systems/distributions before they can be declared stable and rolled out into production. This has to happen independently on each distribution platform.
Having lived and worked with this problem, and recognizing the need for a better solution than the mostly manual process that they and everyone else was using, the founders of Aduva began work on trying to automate the dependency resolution process.
One of the key components of their system was based on recognizing that the package level - at which most people were working - is too high a level for successful resolution. They built a database (the Aduva Universal KnowlegeBase) of dependency information based on the contents of the packages - the individual files that they contain.
By extending the dependency information and including specific dynamic dependency rules down to the file level it becomes much easier to find solutions to dependency problems. Once a set of solutions is found, information stored in the database about the composition of the packages is used to resolve the set of packages with the highest version levels possible to implement a solution. Since information is stored on distribution-specific packages, the system can derive package lists specific to individual distributions for the same dependencies.
The database also contains information on security alerts and errata notifications and fixes for packages and their components, so in building a specific package list the system takes account of these, and will find a path through the dependency graph that avoids as many of them as possible, hopefully all of them. Rarely, when re-evaluating dependencies to add a new application, the only valid path(s) will include components with known security issues. In that case the system delivers its package list, but warns that the list will introduce known security problems, leaving system administrators to decide whether to continue or consult with Aduva's Lab and professional services team to devise a solution.
Keeping the database up-to-date is the key to success. Aduva works closely with Linux distributions, many different Open Source development communities, and various security groups to ensure that it has complete and current information. A set of tools automates and tests much of the process of determining dependencies.
The complete KnowledgeBase allows systems configurations to be generated based on combinations of different packages beyond those directly supported by a given Linux distribution, provided those packages are known to the KnowledgeBase. Of course, in real-world deployments a huge variety of different applications and third-party packages are going to be encountered, more than in the centrally maintained Universal KnowledgeBase. To make sure that the extended dependency requirements encompassing these additional components are taken into account when configuring, a set of tools exists that permits individual customers to create their own KnowledgeBase with dependency rules specific to their particular software. This local KnowledgeBase is then used in conjunction with the central KnowledgeBase to ensure that the specific requirements of local software components are taken into account when determining a stable configuration.
With this core technology in place Aduva has used it as a platform on which to build a set of tools designed to simplify Linux configuration management, application deployment, change management, and patch control for the enterprise. This set of management tools is sold under the name OnStage.
The OnStage toolset provides a very complete set of system configuration management tools, enabling machine types to be defined, a configuration generated for that specific set of machines, and automatically deployed at the click of a button. Changes can be made to any given set of machines such as deploying an application, adding a patch, or changing the system configuration, and the set of changes are validated against the local and central KnowledgeBases and automatically updated to ensure dependency rules are met and pushed to the entire set of machines, either immediately, or deferred until a specific time or other criteria are met. Configurations are recorded at each stage making it trivial to back out any change or set of changes should that be required.
What's unique about the OnStage toolset is that it sits on the KnowledgeBase and takes the uncertainty out of making changes to a stable production platform, which is one more step in making Open Source a viable solution for the enterprise.
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Avere delivers a more modern architectural approach to storage that doesn’t require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbuilding of data centers ...
Feb. 10, 2016 09:00 PM EST
SYS-CON Events announced today that Alert Logic, Inc., the leading provider of Security-as-a-Service solutions for the cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Alert Logic, Inc., provides Security-as-a-Service for on-premises, cloud, and hybrid infrastructures, delivering deep security insight and continuous protection for customers at a lower cost than traditional security solutions. Ful...
Feb. 10, 2016 02:30 PM EST Reads: 423
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 ad...
Feb. 10, 2016 02:30 PM EST Reads: 394
Companies can harness IoT and predictive analytics to sustain business continuity; predict and manage site performance during emergencies; minimize expensive reactive maintenance; and forecast equipment and maintenance budgets and expenditures. Providing cost-effective, uninterrupted service is challenging, particularly for organizations with geographically dispersed operations.
Feb. 10, 2016 01:15 PM EST
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management...
Feb. 10, 2016 12:15 PM EST Reads: 424
SYS-CON Events announced today that VAI, a leading ERP software provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. VAI (Vormittag Associates, Inc.) is a leading independent mid-market ERP software developer renowned for its flexible solutions and ability to automate critical business functions for the distribution, manufacturing, specialty retail and service sectors. An IBM Premier Business Part...
Feb. 10, 2016 12:00 PM EST Reads: 620
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, will discuss the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filte...
Feb. 10, 2016 11:00 AM EST Reads: 189
Cognitive Computing is becoming the foundation for a new generation of solutions that have the potential to transform business. Unlike traditional approaches to building solutions, a cognitive computing approach allows the data to help determine the way applications are designed. This contrasts with conventional software development that begins with defining logic based on the current way a business operates. In her session at 18th Cloud Expo, Judith S. Hurwitz, President and CEO of Hurwitz & ...
Feb. 10, 2016 10:45 AM EST Reads: 248
Fortunately, meaningful and tangible business cases for IoT are plentiful in a broad array of industries and vertical markets. These range from simple warranty cost reduction for capital intensive assets, to minimizing downtime for vital business tools, to creating feedback loops improving product design, to improving and enhancing enterprise customer experiences. All of these business cases, which will be briefly explored in this session, hinge on cost effectively extracting relevant data from ...
Feb. 10, 2016 10:45 AM EST Reads: 107
SYS-CON Events announced today that Pythian, a global IT services company specializing in helping companies adopt disruptive technologies to optimize revenue-generating systems, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Founded in 1997, Pythian is a global IT services company that helps companies compete by adopting disruptive technologies such as cloud, Big Data, advanced analytics, and DevO...
Feb. 10, 2016 10:30 AM EST Reads: 220
With the Apple Watch making its way onto wrists all over the world, it’s only a matter of time before it becomes a staple in the workplace. In fact, Forrester reported that 68 percent of technology and business decision-makers characterize wearables as a top priority for 2015. Recognizing their business value early on, FinancialForce.com was the first to bring ERP to wearables, helping streamline communication across front and back office functions. In his session at @ThingsExpo, Kevin Roberts...
Feb. 10, 2016 09:00 AM EST Reads: 385
As enterprises work to take advantage of Big Data technologies, they frequently become distracted by product-level decisions. In most new Big Data builds this approach is completely counter-productive: it presupposes tools that may not be a fit for development teams, forces IT to take on the burden of evaluating and maintaining unfamiliar technology, and represents a major up-front expense. In his session at @BigDataExpo at @ThingsExpo, Andrew Warfield, CTO and Co-Founder of Coho Data, will dis...
Feb. 10, 2016 09:00 AM EST Reads: 184
SYS-CON Events announced today that iDevices®, the preeminent brand in the connected home industry, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. iDevices, the preeminent brand in the connected home industry, has a growing line of HomeKit-enabled products available at the largest retailers worldwide. Through the “Designed with iDevices” co-development program and its custom-built IoT Cloud Infrastruc...
Feb. 10, 2016 08:00 AM EST
Eighty percent of a data scientist’s time is spent gathering and cleaning up data, and 80% of all data is unstructured and almost never analyzed. Cognitive computing, in combination with Big Data, is changing the equation by creating data reservoirs and using natural language processing to enable analysis of unstructured data sources. This is impacting every aspect of the analytics profession from how data is mined (and by whom) to how it is delivered. This is not some futuristic vision: it's ha...
Feb. 10, 2016 07:45 AM EST Reads: 438
Silver Spring Networks, Inc. (NYSE: SSNI) extended its Internet of Things technology platform with performance enhancements to Gen5 – its fifth generation critical infrastructure networking platform. Already delivering nearly 23 million devices on five continents as one of the leading networking providers in the market, Silver Spring announced it is doubling the maximum speed of its Gen5 network to up to 2.4 Mbps, increasing computational performance by 10x, supporting simultaneous mesh communic...
Feb. 10, 2016 07:00 AM EST
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, will provide an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profes...
Feb. 10, 2016 12:45 AM EST Reads: 202
SYS-CON Events announced today that Men & Mice, the leading global provider of DNS, DHCP and IP address management overlay solutions, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. The Men & Mice Suite overlay solution is already known for its powerful application in heterogeneous operating environments, enabling enterprises to scale without fuss. Building on a solid range of diverse platform support,...
Feb. 10, 2016 12:00 AM EST Reads: 213
One of the bewildering things about DevOps is integrating the massive toolchain including the dozens of new tools that seem to crop up every year. Part of DevOps is Continuous Delivery and having a complex toolchain can add additional integration and setup to your developer environment. In his session at @DevOpsSummit at 18th Cloud Expo, Miko Matsumura, Chief Marketing Officer of Gradle Inc., will discuss which tools to use in a developer stack, how to provision the toolchain to minimize onboa...
Feb. 9, 2016 07:45 AM EST Reads: 108
SYS-CON Events announced today that Fusion, a leading provider of cloud services, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry's single source for the cloud. Fusion's advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including clou...
Feb. 6, 2016 03:30 PM EST Reads: 768
Most people haven’t heard the word, “gamification,” even though they probably, and perhaps unwittingly, participate in it every day. Gamification is “the process of adding games or game-like elements to something (as a task) so as to encourage participation.” Further, gamification is about bringing game mechanics – rules, constructs, processes, and methods – into the real world in an effort to engage people. In his session at @ThingsExpo, Robert Endo, owner and engagement manager of Intrepid D...
Feb. 5, 2016 09:00 PM EST Reads: 829