Linux is fast-becoming the operating system (OS) of choice for many organizations that operate servers that host cloud and big data applications, according to studies by the Linux Foundation and SUSE.

Startups and smaller businesses often choose the open-source OS for their operating servers because so many distributions are freely available. There are hundreds of Linux variants, but only a fraction run the servers a typical Linux system administrator would be responsible for monitoring or maintaining. Unix is the dominant family of web server OSes; up to 15 variations of Linux account for more than half the discoverable Unix-hosted sites.

The most popular commercial product with larger companies is Red Hat Enterprise Linux (RHEL) because it’s proprietary, offers tech support, and can readily show its compatibility with the newest processors. Some organizations start with RHEL, CentOS, Ubuntu, Debian or OpenSUSE, and then modify the system to suit their own requirements.

If you want to focus on Linux system administration, here’s a primer on where to look for jobs. Big companies are showing a growing commitment to the use of Linux systems in these four industries:

Internet

Major players like Amazon, Google and Netflix all rely on Linux for delivering services. A Linux system administrator at Netflix or another company who uses Amazon Web Services would have intimate knowledge of Amazon Linux AMI. Facebook and Twitter each use a Linux variant that has been tweaked in-house. For these types of organizations, open-source Linux distributions can deliver a lower cost of ownership than even the lowest-priced proprietary cloud options because of the many servers needed to offer Software as a Service on a global scale.

Finance

Wall Street, for some time now, has been a good place for job seekers to look for openings in Linux system administration. A number of markets trade using solutions built on a Linux stack, including the NYSE Euronext, London Stock Exchange and Chicago Mercantile Exchange. Financial exchanges rely on Linux for one of the same reasons Internet companies do: Communications architectures are stable when handling large numbers of simultaneous, roundtrip messages quickly.

Insurance

Large insurance companies also build operating environments on Linux. AIG, for example, uses Red Hat and SUSE variants in its architecture. Health insurer, Cigna, was named “Innovator of the Year” last year in the Red Hat Innovation Awards. Scalability and tight security top the list of reasons some insurers are choosing Linux today.

Healthcare

Red Hat skills come in handy for Linux system administration jobs at healthcare organizations such as Beth Israel Deaconess Medical Center. Many Debian “pure blends” — subsets of the Debian GNU/Linux distribution — address the specific needs of healthcare providers and researchers by packaging the kernel with drug databases or electronic medical record systems.

Other industries

Government, education and military are other sectors increasing their reliance on Linux system administration. Expect to hear more in the future about innovative companies using Linux systems to support advances in autonomous vehicles, wearable devices, and other “smart” combinations of hardware and software. The trend toward increased use of Linux in the enterprise is good news for technology professionals with Linux skills — and especially those with a background in Linux system administration.

Check out our Salary Guide to see the starting pay for Linux pros in your city.