More than 20 years after Linus Torvalds developed Linux, the operating system remains a force in the computing industry. While Linux is not widely used on desktops (making up just over 2.4% of the overall desktop operating system market share in January 2019, according to NetMarketShare), it is extraordinarily strong on the web server side, where it enjoys a market share of almost 54%.
IT professionals invest considerable time learning about server computing for everything from installation, configuration, maintenance and virtualization to application support and security. This also means that many IT professionals are working with and around Linux operating systems daily, often alongside Windows and various UNIX OS brands as well.
The best of the Linux certifications vie for considerable mindshare among IT professionals and present an interesting mix of distribution- or brand-agnostic credentials alongside some pretty formidable vendor-specific credentials. There are multiple well-elaborated certification ladders available to those interested in learning, using, and mastering the Linux operating system environment and all the many bells and whistles it supports.
The results of a job search we conducted on several popular job posting sites show which Linux certifications employers are looking for when hiring new employees. While results vary from day to day (and job board to job board), this table reflects those Linux-related certifications that employers were seeking in the U.S.
Job Board Survey Results (in alphabetical order, by certification)
Certification | Total | ||||
GCUX (SANS GIAC) | 30 | 30 | 55 | 12 | 127 |
Linux+ (CompTIA) | 1,045 | 1,339 | 779 | 547 | 3,710 |
LPIC (LPI) | 38 | 41 | 247 | 44 | 370 |
Oracle Linux OCA | 27 | 31 | 33 | 12 | 103 |
Oracle Linux OCP | 61 | 69 | 69 | 25 | 224 |
RHCA (Red Hat) | 89 | 102 | 190 | 38 | 419 |
RHCE (Red Hat) | 467 | 553 | 754 | 267 | 2,041 |
RHCSA (Red Hat) | 417 | 504 | 667 | 241 | 1,829 |
We found that for nearly every certification category listed above, the number of national jobs postings mentioning that certification has increased, in some cases substantially, since we surveyed the same job sites a year ago. Linux system administrators and engineers can expect average earnings in the low $70s and upward, depending on the job role. PayScale lists $70,194 as the average salary for Linux system administrators ($52,000/low and $101,000/high). Glassdoor reports earnings for Linux system administrators averaging $68,884, Linux system engineers at $99,348 and senior Linux system engineers at $122,071.
GCUX: GIAC Certified Unix Security Administrator
The Global Information Assurance Certification (GIAC) program is part of SANS, a highly regarded source of instruction and research in the information security field. SANS also provides breaking news, operates a security alert service and serves on all kinds of government, research and academic information security task forces, working groups and industry organizations.
The SANS GIAC program encompasses 37 information security certifications across several categories, such as cyber defense, penetration testing, incident response and forensics, management, audit, legal, developer and industrial control systems. The GIAC Certified UNIX Security Administrator (GCUX) falls under its Cyber Defense category, and aims at professionals who install, configure, monitor, secure and audit both Unix and Linux systems.
GIAC certifications must be renewed every four years by earning 36 continuing professional experience (CPE) credits. Also, credential holders must pay a certification maintenance fee of $429 every four years.
GCUX Facts & Figures
Certification Name | GIAC Certified Unix Security Administrator (GCUX) |
Prerequisites & Required Courses | None; SEC506: Securing Linux/Unix training recommended (classroom, on demand, self-study or private; $6,610) |
Number of Exams | One exam (75 questions, two hours, minimum passing score 68%) |
Cost per Exam | $1,899 without training (called a GIAC certification attempt; includes two free practice exams) $769 as part of a training course $769 retake fee $429 certification renewal Exams administered by Pearson VUE. |
URL | https://www.giac.org/certification/certified-unix-security-administrator-gcux |
Self-Study Materials | Practice tests available on the GIAC exam preparation page (two tests included in exam fee; additional practice tests are $159 each). No GCUX-specific study guides found; GIAC recommends searching for self-study materials based on the GCUX objectives' knowledge areas and getting practical experience. |
Linux+ (CompTIA Linux+ Powered by LPI)
CompTIA exercises extraordinary certification clout at the entry level in many IT niches. This nonprofit has shown itself as willing to team up with more focused IT organizations, associations and consortia to combine their own market reach and visibility with niche smarts and subject matter expertise on loan from various partners.
One great example is the organization's partnership with the Linux Professional Institute (LPI), which resulted in the CompTIA Linux+ Powered by LPI credential. This unique certification replaced the original CompTIA Linux+ certification in 2010 and uses the same two exams required for LPIC-1 certification.
As a result of this partnership, IT professionals who are serious about Linux can earn both the Linux+ credential and the LPIC-1 at the same time. Candidates must first earn the Linux+ credential and then submit a request to CompTIA asking that their results be sent to LPI to obtain the LPIC-1 certification. CompTIA exam records are confidential, so candidates must request that their records be forwarded to LPI when taking the CompTIA Linux+ Powered by LPI exams.
Earning the CompTIA Linux+ Powered by LPI requires candidates to pass two exams. The first covers system architecture, installation and package management, GNU and Unix commands, devices, file systems and standard file system hierarchies. The second exam digs into command shells, scripting and data management, user interfaces and desktops, administrative tasks and activities, basic system services, networking fundamentals and security topics. The CompTIA Linux+ Beta Exam (XK1-004) closed as of October 22, 2018, though candidates who took the exam prior to the end date can still access those scores and apply a passing grade to their Linux+ certification. The replacement Linux+ 104 exam based on this beta exam will become publicly available in April of 2019.
Note that the Linux+ credential is valid for life.
CompTIA Linux+ Powered by LPI Facts & Figures
Certification Name | CompTIA Linux+ Powered by LPI |
Prerequisites & Required Courses | None required |
Number of Exams | Two exams: LX0-103 and LX0-104 (60 multiple-choice questions each, 90 minutes, 500 required out of 200 to 800 scale to pass). Note that the LX0-104 Beta Exam is no longer offered as of October 22, 2018; the replacement 104 exam becomes publicly available in April of 2019. |
Cost per Exam | $200 per exam; prices vary by geography |
URL | |
Self-Study Materials | CompTIA maintains a list of training materials and additional study options, including links to study guides, exam crams, practice tests, online and classroom training, CertMaster, and more. Additional third-party reference and review materials can be found on Amazon. |
LPI (Linux Professional Institute) Certifications
The Linux Professional Institute (LPI) started up in October of 1999, almost one decade after Linus Torvalds began his pioneering efforts on the Linux kernel. Since then, LPI has become one of the leading certification providers on Linux topics and technologies. Given the organization's distribution-agnostic approach to Linux, it offers excellent coverage of a platform that's available in many forms and flavors in today's marketplace.
The LPI Certification (LPIC) program is available in three distinct levels:
- LPIC-1: Linux Administrator: A junior-level Linux certification with no prerequisites. Candidates must pass two exams that cover basic Linux skills, including installing and configuring Linux on a workstation, working at the command line, performing basic maintenance tasks, and making LAN or internet connections. While you can obtain the LPIC-1 credential directly from LPI, candidates should consider obtaining the CompTIA Linux+ Powered by LPI credential first, which qualifies you for both the Linux+ and LPIC-1 credentials.
- LPIC-2: Linux Engineer: An advanced-level Linux certification that requires an active LPIC-1 certification. Candidates must pass two exams that cover significant Linux skills and topics. The first exam covers the kernel, system startup, file system and devices, advanced storage administration, network configuration, system maintenance and capacity planning. The second exam covers web services, file sharing, network client management, email services, system security and troubleshooting, and domain name servers.
- LPIC-3: Linux Enterprise Professional Certification: A senior-level Linux certification that requires an active LPIC-2 and passing any single exam in the 300 series. Valid exam IDs currently include 300: Mixed Environment, 303: Security, and 304: Virtualization and High Availability. The Mixed Environment exam covers Samba (domain integration, user and group management, name services, share configuration and so forth), plus OpenLDAP, and working with Linux and Windows clients. The Security exam covers network, operations and application security, as well as cryptography and access controls. High availability cluster storage and management, along with virtualization, are covered in the Virtualization and High Availability exam.
In addition to the LPIC-1, 2 and 3 credentials, LPI also offers an entry-level credential, the Linux Essentials Professional Development Certificate (PDC). Linux Essentials focuses on foundational skills, such as creating and running simple scripts, restoring compressed backups and archives, working with the command line, Linux operating system basics, FOSS, and users/groups and file permissions for public and private directories. Linux Essentials is a great way to get started while gaining the skills and knowledge needed for the more challenging LPIC credentials.
LPI's newest certification is the LPIC-OT DevOps Tools Engineer, which recognizes the effective use of tools for collaboration during system and software development. There are no prerequisites, and the single exam lasts for 90 minutes and has 60 questions.
LPIC credentials are worthwhile for IT pros whose chosen Linux distributions do not warrant their own certification programs, and for those seeking broad, vendor- and distribution-neutral coverage of Linux topics, tools and technologies. They are popular among IT pros and in demand among IT employers.
LPIC-1, LPIC-2 and LPIC-3 Facts & Figures
Certification Name | LPIC-1: Linux Administrator |
Prerequisites & Required Courses | LPIC-1: None, Linux Essentials recommended LPIC-2: Active LPIC-1 certification LPIC-3: Active LPIC-2 certification plus completion of one of the 300 series specialty exams Training is recommended but not required |
Number of Exams | LPIC-1: Exam 101-500 and Exam 102-500 LPIC-2: Exam 201-450 and Exam 202-450 LPIC-3: One of the 300 series exams: Mixed Environment (Exam 300-100) Security (Exam 303-200) Virtualization and High Availability (Exam 304-200) |
Cost per Exam | $200 per exam. Exams administered by Pearson VUE. Linux ID required to register. |
URL | http://www.lpi.org/our-certifications/summary-of-certifications |
Self-Study Materials | Study guides, courseware knowledge packs, eLearning courses, exam crams, practice tests, online and classroom training, Linux Academy subscriptions and more are available at LPI Exam Preparation, LPI Marketplace and Amazon. |
Oracle Linux OCA & OCP
When Oracle bought Sun Microsystems in 2010, it acquired a rich and deep UNIX tradition. Oracle started phasing out Solaris almost immediately after finalizing the Sun acquisition.
Today, Oracle offers associate- and professional-level certifications based on Linux rather than harking back to any kind of UNIX roots. These certifications retain enough of their Sun roots, however, so that courses are not mandatory prerequisites to taking the exams for the two Oracle Linux certifications currently available.
As with other vendor-specific Linux certifications, Oracle's are most appealing to those who work with or around that distribution, or who wish to work for employers who use those distributions.
OCA and OCP Facts & Figures
Certification Name | Oracle Certified Associate (OCA), Oracle Linux 5 and 6 System Administrator |
Prerequisites & Required Courses | OCA: No prerequisites. Recommended training: Oracle Linux System Administration OCP: OCA Linux 5 and 6 System Administrator or Linux Administrator Certified Associate (now retired). Recommended training: Oracle Linux System Administration |
Number of Exams | OCA: One exam, 1Z0-100 Oracle Linux 5 and 6 System Administration (150 minutes, 80 questions, 61% to pass) OCP: One exam, 1Z0-105 Oracle Linux 6 Advanced System Administrator (150 minutes, 97 questions, 61% to pass) |
Cost per Exam | OCA: $245 |
URL | https://education.oracle.com/oracle-linux/oracle-linux-administration/product_295?certPage=true |
Self-Study Materials | Oracle offers online and in-class training for its credentials, with hit-or-miss coverage for them on the aftermarket. Start with Amazon searches — check exam IDs 1Z0-100 and 1Z0-105 to get a sense for what's available. |
Note: Though there is now an OCA and OCP exam available for Oracle Linux 7 System Administrator, Oracle has yet to announce this new certification or release the details of new Linux 7-based certification tests for OCA and OCP candidates.
Oracle Linux 6 Certified Implementation Specialist Certification
The Oracle Linux 6 Certified Implementation Specialist Certification is a certification available for those who sell, design, configure and implement Oracle Linux 6 solutions. Though any candidate can complete this certification, it is most typically achieved by Oracle partner implementation personnel with strong foundational experience in Linux and previous field experience implementing Linux 6.
Red Hat RHCSA, RHCE & RHCA
If there's one major star in the vendor-specific Linux certification firmament, it's got to be Red Hat. The company has major market presence and serious duration as a commercial provider of Linux platforms and technologies.
Red Hat offers a typical administrator, engineer, architect certification ladder. Unlike many other such programs, however, it offers highly regarded and valued credentials at each rung, along with demanding and hands-on oriented exams and an excellent training curriculum to match. All exams for the following Red Hat certifications are performance based and last two hours or longer.
The giveaway for Red Hat certifications is that all come with acronyms that start with RH, as follows:
- Red Hat Certified System Administrator (RHCSA): This foundation certification vets essential skills in handling files, working at the command line and using system documentation, along with managing systems (boot up, identifying processes, start/stop virtual machines, controlling services), configuring storage partitions and logical volumes, and more.
- Red Hat Certified Engineer (RHCE): This cornerstone certification is designed to test and validate the skills and knowledge necessary to work as a senior-level Linux system administrator. Topics covered include advanced IP routing and services, managing runtime kernel behavior, working with iSCSI, automating maintenance tasks with shell scripts and working with networking services for Web, FTP, NFS, SMB, SMTP, SSH and more. An RHSCA is a prerequisite for the RHCE.
- Red Hat Certified Architect (RHCA): Red Hat's pinnacle certification offers two paths to certification, depending on which prerequisite advanced Red Hat certification credentials you have already completed: Red Hat Certified Enterprise Microservices Developers (RHCEMDs) and Red Hat Certified JBoss Developers (RHCJDs) can earn an RHCA in Enterprise Applications, and Red Hat Certified Engineers (RHCEs) can earn an RHCA in Infrastructure. In general, the five additional exams that must be passed to achieve the RCHA in either Infrastructure or in Enterprise Applications are specific to each area of specialization, though a few of the tests can be used to satisfy the five exam requirement in both RHCA tracks. A number of previously available certification exams have been discontinued for new RHCA candidates and renewals, though those exams can still be applied to the RHCA certification if you've already passed them. Find out more about discontinued exams that can be counted towards the RHCA credential on the RHCA page under the Candidate Guidance tab.
Because Red Hat Linux is widely used in the business world, the RHCA certification is an excellent choice for those interested in a more platform-focused path into the Linux world. Of course, for those who already work with or around Red Hat, it is a natural certification choice as well.
RHCSA, RHCE and RHCA Facts & Figures
Beyond the Top 5: More Linux certifications
Outside the top five Linux credentials and programs covered in this article, other Linux certifications may be worthy of your time and attention.
The Linux Foundation, a membership-based organization, promotes the development of the Linux kernel through collaboration, conferences and education. The organization's small but respected certification program includes the Linux Foundation Certified System Administrator (LFCS) and the Linux Foundation Certified Engineer (LFCE).
IBM continues to offer a handful of Linux-related certifications. One certification of interest is the Certified Database Administrator, which continues to be in demand for those running DB2 on Linux, Unix and Windows systems.
Many industry experts, including Steven J. Vaughn-Nichols, a long-time user and expert on Linux and Unix operating systems, say that certifications can be an important ingredient in a job candidate's qualifications. But interviewers should also pay close attention to how many Linux systems candidates have set up, managed or used to get a sense of the scale and scope of their experience.
In other words, when you see a web hosting service advertising for Linux jobs, they're not looking for people who've installed and used Linux at home or in a small business setting; they're looking for professionals who've set up and managed Linux in a highly distributed and virtualized data center environment, with lots of complex networking and services coming into the mix.