Nexus 2.0 is coming. Join Jason for the first demo.
Join us Tuesday, February 21 at 11:00AM (GMT-0500) for a 30 minute demonstration of Nexus 2.0, with Jason van Zyl, Sonatype Founder & CTO. You’ll see all the new features and learn how Nexus 2.0 will help you:
- Avoid downtime by using a highly available architecture
- Improve repository management with enhanced component information
- Standardize on a single repository for .NET, Java, and OSGi
If you register, you’ll also receive access to the recording after the event. So if something comes up and you can’t make it, you won’t miss out.
A Simple Reminder for Maven/Gradle/Ivy Users: Proxy Central
Over the course of the past few years, I’ve interacted with hundreds of people when talking about build tools and repository management. It continues to surprise me how many people don’t realize where these artifacts come from. When you run a build and these JARs just show up alongside all of their dependencies, it’s like magic to most people. If you know how it works, it’s very obvious to you that running a repository manager is the right thing to do. This post is a reminder to everyone using build tools that rely on Central: take time to proxy Central with a repository manager.
“Wait, that’s how Central works?”
There’s something so automatic about dependency management in Maven that it often takes people a few months to understand exactly where those JAR files are coming from. In an 8 hour Maven class, I get to dependencies in the third hour, and after describing Central, what it is was like before Central, how metadata is stored in a repository alongside binaries, transitive dependencies, etc…. it all falls into place, and people realize that this simple thing they’ve grown accustomed to is only easy because of a ten year effort to refine the model, the creation of a support structure for source forges at places like Oracle and Google, and a constant investment in infrastructure.
On the one hand, it’s a great success that Central is, for the most part, an invisible utility that supports developers. On the other hand, it’s the kind of thing that people can start to take for granted very easily.
For example, a few months ago I spoke to someone who worked in an environment disconnected from the internet for security reasons. This individual was talking about how limiting it was to have to download JARs from open source projects manually and assemble them in a project. His words were: “It’s like programming Java in 2001 again.”
How can you help?
Imagine millions of developer spread all over the world: different time zones, different applications, but they all hit the same service: Central. Some regions have more developers than others so we certainly see peaks in usage throughout the day, but in general, Central’s serving thousands of files throughout the world at any given time during the day.
Maybe someone just installed Maven for the first time, or maybe they blew away a local repository, with numbers like these we see a world that has a constant appetite for artifacts. It isn’t a problem for Central, and I’m not writing this because Central is falling down on the job. Central can handle it, but it certainly isn’t the most efficient way to support millions developers. It isn’t a good use of network bandwidth, and it isn’t a good use of energy to constantly cart around the same static JARs over and over and over again when the solution is so easy.
If everyone who used a build tool that interacted with Central adopted a repository manager such as Nexus we’d have a faster, more responsive system. Central’s maintainers would be focused less on addressing the occasional runaway build and could spend more time and resource on increasing availability and functionality of this essential service.
Broken Builds
The other factor playing into this is that Maven builds only download releases once. It isn’t like these build tools are repeatedly returning to Central to download release artifacts over and over again.
Well… actually… that isn’t true, we’ve seen some installations of Hudson configured to delete a local repository before every build placing a high load on Central. Imagine a build that downloads 50 MB of dependencies running once every 5 minutes. That’s one build consuming ~14 GB a day never mind the time wasted downloading static artifacts. While these broken builds are the exception, they do still show up from time to time. Central can handle the load, but imagine 1000 of these broken builds running continuously and you can see the challenge.
A Simple Reminder: Please Proxy Central
We’re constantly watching the performance of the system and making sure it stays up and running for an entire world of developers. If you use a build tool that hits Central whether it is Buildr or Maven or Gradle or Ivy, you can help us by running a Nexus instance.
Even if all of your builds work perfect, running a local Nexus instance helps preserve Central as a public, free resource and it will lead to faster, more responsive builds.
Sizing Nexus: How much space do you need?
You’ll want to make sure that you run your repository manager on a server that is up to the task. The last thing you need is for Nexus to run out of space during a critical release because it is running on inadequate hardware. Disk space is cheap, broken builds are not.
In this post, I focus on storage requirements for Nexus. I discuss general recommendations and point you at resources we’ve developed to help you come up with accurate estimates for how much disk space you’ll need.
Disk Space
Disk space is going to be the critical parameter for a Nexus installation. At its core, Nexus is simply a collection of files and a set of services to index and serve these files. If you integrate Nexus into your development process and come to depend on it as a collaboration mechanism, you can easily consume hundreds of gigabytes (or even terabytes) of space.
Coming up with a simple guideline for storage requirements is difficult as it depends on a number of factors: How many projects do you have? How large are the artifacts being deployed to Nexus? How frequently are these artifacts deployed? and How long do you keep your releases? How much open source are you consuming from Central? How often do you update external dependencies? and How many 3rd party artifacts do you need to upload?
If you deploy artifacts to Nexus, your internal, hosted repositories are what will end up consuming the most space over time. At a large organization with hundreds of projects and frequent releases, it is very easy to create systems that consume a surprising amount of space. If you are interested in diving into the details and coming up with an estimate for your organization, watch “Getting Scientific about Sizing Nexus”.
An Initial Starting Point
While some of our engineers like to aim high with an initial recommendation of 250-500 GB, I like to aim a little lower. Sure, if you are rolling Nexus out to a 5,000 developer installation with thousands of projects, you may very well want to start with 1 TB. On the other hand, if you are gradually rolling Nexus out to a department or two, you should start with a more reasonable number: 50 or 100 GB.
I recommend starting with 50 or 100 GB, and I also recommend being prepared to expand that number as needed. Starting with this smaller number avoids the problem of procuring a huge chunk of disk space only to watch it sit idle for the months (or years) it will take you to consume all this space. Aim low, plan to expand.
Conclusion
Your initial estimate for disk space consumption is going to be just that, an estimate. Having set up scores of Nexus instances for organizations of all sizes, my experience has been that you’ll want to do some ballpark estimates and then multiply that estimate by a factor of two or three. When you connect systems like Hudson to Nexus and deploy snapshots from every integration build, you’ll appreciate the extra space.
As you start to use Nexus, you’ll have to tweak your scheduled jobs to make sure that you are periodically removing old snapshots and regularly keeping an eye on storage. If you expand the number of projects or developers using a Nexus instance, you’ll want to revisit some of these initial estimates and make sure that your system has enough storage to keep track of all the artifacts it is caching and storing.
Releases Are Forever?
Releases are forever, right? Once you’ve pushed an artifact to a hosted release repository it is etched in stone, and changing it is a bad practice. That’s what we’ve been saying since we launched Nexus, but there are situations that call for old releases to be deleted. In fact, there are situations that require the deletion of old releases? Otherwise, you’d be paying for terabytes of useless data storage. (more…)
Webinar Replay Now Available: Nexus 2.0 Sneak Preview
Thank you to everyone who made it to our Nexus 2.0 Sneak Preview webinar last week! We had a fantastic turnout and received tremendous interest from our users in the features that are coming in Nexus Pro 2.0, including:
- Integrated security and licensing reports to discover problematic components
- Improved availability with our new Nexus Availability Architecture
- Ability to manage both Java and .NET components from a single repository
The webinar recording is now available here.
Special pre-release pricing is available for Nexus Pro 2.0. Check out the webinar or contact a representative for more information.
