Red Hat has cut the $99 price of its Linux developer subscription to zero, for penguins building cloud microservices using containers.

The company today is expected to start giving away its Red Hat Enterprise Linux (RHEL) subscription for free as part of the existing Red Hat Developer Program.

The free license runs in tandem with the existing $99 developer license for those already paying, with Red Hat assessing whether it should continue charging.

It follows the introduction of a free developer license for the JBoss application server, FUSE, Drools and BPM suite 18 months ago.

Like these, the RHEL license applies only to development, not production environments. Unlike these, it's RHEL that's turned Red Hat into a profitable Linux vendor and the first past $1bn and then, last year, $2bn in revenue.

While this targets devs, however, Red Hat's introduced the free license to ensure its Linux becomes a player in continuous lifecycle management of cloud services.

Red Hat wants to ensure RHEL gets used from dev and test through to production rather than, as can happen now, have devs start out using free CentOS or Fedora and then – potentially – switch to RHEL for production or – more likely – stay on the free stuff.

It's that need to switch that introduces the risk of coding breaks, and that introduces migration hassles and is a conclusive factor in preventing lifecycle management.

That's a no-no for today's meme du-jour of immutable infrastructure – servers build using code that you don't alter, but are built for purpose and get dumped if, or when, they're done with or get broken. Immutable infrastucture cannot work if there exist minute variations in different servers or different versions of the same server.

One operating system all the way down the line is one possible way to avoid this.

Harry Mower, senior director of the Red Hat developer group and former Microsoft man, told The Reg that while RHEL doesn't have a huge stake in immutable infrastructure today, Red Hat wants to avoid a problem before it starts.

"We are trying to get ahead of a few problems we anticipate we might encounter in the market, where we see developers and development shops move to continuous lifecycle pipelines. Using containers in that process requires that you have an immutable environment where you have a precise replica of the environment.

"We aren't seeing customers screaming about it today, but don't want to ever see them scream about it."

Announcing the free license, Red Hat also pointed out it's targeting those coding for Linux from Windows machines and Mac.

Red Hat buddied up with Microsoft in November last year on cloud. RHEL, JBOSS and middleware would run natively on Microsoft's Azure cloud with plans for "full access to .NET across Red Hat technologies," Mower said.

RHEL became the "primary development and reference operating system for .NET Core on Linux." ®