Everett Toews

Helping you shave narwhals

The Dual Advantage of Multi-Cloud Toolkits

17 Jan 2014

The goal of using a multi-cloud toolkit is avoiding cloud vendor lock-in. I examined why avoiding vendor lock-in is important in Keep the Cloud Honest. Toolkits such as Apache jclouds (Java), Apache libcloud (Python), Fog (Ruby), and pkgcloud (node.js) enable this by allowing you to write code that will work the same across multiple clouds such as Amazon Web Services (AWS), DigitalOcean, Google Compute Engine, and Rackspace.

Exactly how the toolkits achieve this matters a great deal. Most people think it’s those interfaces within the toolkit that work the same across multiple clouds that are responsible for this. They’re right but there’s more to it than that.

Those interfaces are sometimes called abstraction layers or portable APIs. First let’s look at the portable APIs. I’m most familiar with jclouds so I’ll use examples from our community.

Portable APIs

These are the APIs that allow you to write code that can run with multiple clouds.

For example, you can write code that stores an object in the cloud and that exact same code can run with storage services such as HPCloud Object Storage, AWS S3, and Microsoft Azure. Companies like Maginatics use this to great effect to store billions of objects across many clouds. Smaller projects like ElasticInbox use it to increase redundancy using multiple clouds.

The same goes for computing resources. You can write code that starts a virtual machine in the cloud and that exact same code can run with compute services such as Rackspace Cloud Servers, CloudSigma, and SoftLayer. This allows a Jenkins plugin to start slaves on different clouds or Apache Stratos to run it’s Platform as a Service across multiple clouds.

The portable APIs do this by supporting features that are common across many clouds. Because these features are common, they are naturally a subset of all of the possible features that a cloud may provide. But what happens when your application requires a feature that isn’t common and isn’t part of the portable API?

No problem. All of the multi-cloud toolkits allow you write code to specific APIs for each cloud so you can use those particular features. But then you’re seemingly headed down the path of vendor lock-in. Not so.

Easing The Transition to Another Cloud

Without multi-cloud toolkits, the normal course of action for a developer working with a cloud is to download the toolkit for that cloud only and write their code using it. For example, a developer downloads the AWS Java toolkit and uses it throughout their application with AWS.

To switch to another cloud, not only do the developers have to tear out the AWS Java toolkit and all of the associated code. They have to download the toolkit for another cloud and that toolkit is going to have a different architecture, different idioms, and a different programming paradigm. Developers will have to understand how it works, learn its nuances and idiosyncrasies, and re-architect their application around it. This is a high cost proposition and high barrier to leaving AWS. Lock-in pure and simple.

With multi-cloud toolkits, a developer will download the multi-cloud toolkit and write their code using it, possibly using specific APIs for particular features to a cloud. For example, a developer downloads the Apache jclouds toolkit and uses it throughout their application with Rackspace.

To switch to another cloud, a lot of code will have to be replaced and refactored but they do not have to download another toolkit. All of the cloud providers in jclouds are architected and written in a similar style so there is a lot of consistency between them. Developers already understand how it works, and are comfortable and efficient with it. They can use their intuition when transitioning their code to a new cloud provider. This is a lower cost proposition and a lower barrier to leaving Rackspace. No lock-in. You can choose the cloud provider that works the best for you.


The value of multi-cloud toolkits is not only in their portable APIs but also in how they can ease the transition from one cloud to another by allowing the developer to reuse all of the knowledge and experience they have gained with the multi-cloud toolkit. Don’t get locked into a cloud provider because it’s too expensive to change your code. Choose a multi-cloud toolkit.