It is posted on the Google Code site, where the open source code is available for download: Part 1, Part 2, and Part 3.

Let us know what you think in the comments!

Other regions to come soon!

This means that you can now scale your website (or individual components of your web stack) easily on an RPM package-based system. Two roles are available, ‘Base’ (which is ready to be customized into roles like Application servers, or ffmpeg transcoding servers) and ‘MySQL’ (which is ready to scale, using version 5.0.77). Both are EBS-based, which means that they can be start / stopped like any virtual machine, and run CentOS 5.4 (32 and 64bit).

US West, Europe, and Asia-Pacific regions to follow soon, as well as more flavors of linux.

These Roles use the all-new Scalarizr, our lightweight python agent that reports usage metrics back to Scalr to trigger the scaling. More on the Scalarizr in a later post.

Cheers,
The Scalr Team

Next Thursday (August 26) at 1:00 AM PST, we will add a new, non-cloud server to our infrastructure to improve fault-tolerance and performance. No UI downtime is expected, but there is a small chance that you might not be able to login a few times.

This is the last upgrade required to achieve full geographic fault-tolerance. Our nameservers are spread across 4 network-independent datacenters and two continents, and our http servers, polling servers, and database servers will all be fully redundant after the server addition.

Cheers,
The Scalr Team

We added the set of pre-made Scalr roles to the Asia-Pacific region, so you can now scale in the most populated region of the world. This includes among others the NGINX load balancer, the Apache and Tomcat application servers, and MySQL database server.

You can set each of those to scale based on any of the Scalr metrics, such as Load Average (CPU), Free RAM available to the system, Network I/O, a fixed schedule, http request/response time, among others.

The ssh extension that we use to upload changes to our nameserver configuration file (named.conf) segfaulted, causing corruption in it. This corrupted configuration was replicated to other name servers to propagate changes.

Timeline and resolution

Wed Aug 4 10:47 PST 2010 – The ssh extension used for transporting nameserver updates segfaulted.
The named.conf configuration file that was being transported was corrupted in the process, and was then synchronized to other nameservers.

Wed Aug 4 10:55 PST 2010 – A client reported an issue with DNS.
We found the corruption and started working on a fix.

Wed Aug 4 11:05 PST 2010 – We manually generated a new named.conf file, and uploaded it to the nameservers.
The new valid named.conf propagated to the other nameservers.

Prevention

To prevent this from happening in the future, we are taking the following action:

We will cease to use ssh as transport and will create a local daemon which will update named.conf directly from our database on each NS server. This daemon will be ready within the next 24 hours.

Estimated Impact

18 minutes.

Regards,
The Scalr Team

• New! Scalarizr. Allows you add a node to be managed by Scalr. Supported os: Ubuntu 8.04, Ubuntu 10.04, Debian 5, CentOS 5, Fedora 8, Fedora 12, Fedora 13 (This list will be extended within the next releases)
• New! DNS manager. Increased stability and speed, decreased number bugs and fails.
• New! Apache virtualhosts manager.
• New! API 2.0. Added methods for creating DNS zones and Server snapshots. Please note that this API replaces and is not compatible with the previous API.
• Replaced “Synchronize to all” with “Create server image” instead. New object – BundleTask.
• Improved EBS (network storage) and ELB (load balancer service) management, fixing tons of issues.
• Improved MySQL status page.
• Improved Scaling algorithms and logging. You can now see why your role was scaled. Up or down.
• Improved UI. Faster, with a new page for checking all information about servers and farm roles.
• AWS platform changes: Added Asia-Pacific region, and RDS (mysql service) as cloud platform.
• Scalr will show warnings in UI if issues have been posted on status.aws.amazon.com.

Open Stack is an “open source, open standards” stack for Cloud Computing, which includes Compute (like EC2) and Storage (like S3). You can find all the code for Open Stack on Launchpad, as well as the other sub-projects like the iPad and iPhone apps.

This is a huge leap forward, probably the single most important announcement in the industry since EC2.

How does Scalr play into this?

We’re thinking about it. Scalr is currently licensed under the GPL v2, and we’d have to change that to the Apache License which the Open Stack charter requires. The Apache License precludes the dual licensing business model, in which we sell a commercial license to use Scalr for those averse to the GPL.

Open Stack also has a nascent Web UI, with a subset of Scalr’s functionality.

If anyone wants to weigh in here, their thoughts are welcome.

The problem is that Cron jobs, which are scripts that are executed periodically, were up until now tied to individual servers. When that individual server failed, the Cron job wouldn’t be executed. When that server was scaled, it would be executed once per server. This means that the tasks you set to be executed once per hour, could be executed 5 times in the hour, or not at all – not very reliable, to say the least.

Scalr based the Scheduler off Apache ZooKeeper, which is a part of Hadoop. It is a centralized service for providing group services, especially distributed lock services. The Scheduler extends Scalr’s scripting interface, and allows you to write scripts and set their execution schedule and scope: once on all servers, every hour on a subset of servers, daily on a single server, and any other combination!

As always, the code is available on Google Code and delivered as a service at scalr.net.

***

You can find the Scheduler under the Tools menu, found at the top when logged in:

You can schedule tasks to be executed periodically using the Scalr Scheduler

To add a Cron job or schedule a script, click the + icon next to the Search box:

Click the + icon to add a new cron job or to set a schedule for a script

You can then select the script to be executed, choose the parameters for it, schedule a time or interval, and run!

Configure the cron job's interval, parameters, and more

We pushed a new release out this week, a few of you might have seen this already.

This is a rather important update, as it brings us closer to Scalr 2.0, which will extend Scalr to all Operating Systems and environments. You can find the complete list of features added below, and I’d like to highlight the Scheduler, the improved Monitoring system, as well as the shortcuts to your farms added to the top menu.