Linux Systems Administrator

Job Type: Full-Time Location: Killeen, Texas Department: Systems Support

We are looking for an experienced Linux Systems Administrator to administer, monitor, secure, and maintain enterprise Linux environments.

The ideal candidate will have strong hands-on experience with RHEL, Ubuntu, and CentOS, along with familiarity with Windows Server, VMware, and containerized environments such as OpenShift and Kubernetes.

This role will provide Tier 2/3 technical support, troubleshoot complex infrastructure issues, support enterprise applications, and collaborate closely with development, DevOps, and security teams.

• Administer, monitor, maintain, and troubleshoot Linux systems, including RHEL, Ubuntu, and CentOS.
• Install, configure, secure, and optimize Linux services such as systemd, SSH, Apache/Nginx, cron, and related services.
• Perform Linux system upgrades, patching, configuration, and security hardening.
• Provide Tier 2/3 support for escalated server and infrastructure issues.
• Identify, research, and implement Linux and OpenShift solutions and applications.
• Support and troubleshoot enterprise applications and their underlying server environments.
• Manage Linux security administration in collaboration with information security teams.
• Monitor system health, performance, availability, and capacity, and proactively address potential issues.
• Collaborate with development, DevOps, infrastructure, and security teams to support application and infrastructure requirements.
• Provide technical guidance and support to IT teams on Linux configuration and administration.
• Maintain awareness of Linux and OpenShift updates, changes, and new releases, and communicate relevant changes to stakeholders.
• Work with vendors and internal teams to resolve technical issues and support applications and infrastructure.
• Create and maintain accurate technical documentation, processes, and standard operating procedures.
• Participate in a weekly on-call rotation to respond to after-hours infrastructure issues.
• Travel to other data centers or company locations as required.
• Perform other duties and assignments as needed.

• Provide administration and support for Windows Server environments and related services.
• Working knowledge of Active Directory, Group Policy, DNS, DHCP, and PowerShell.
• Administer VMware vSphere/ESXi environments, including:
• Virtual machine deployment
• Resource management
• VM administration
• Snapshots
• Basic troubleshooting

• Support and administer OpenShift/Kubernetes environments.
• Install, configure, maintain, upgrade, monitor, and troubleshoot OpenShift/Kubernetes clusters.
• Support containerized applications using OpenShift, Kubernetes, or Docker.
• Stay current with developments, updates, and best practices in container orchestration technologies.

• Ensure compliance with security standards, patching schedules, and organizational policies.
• Apply security hardening practices to Linux and server environments.
• Understand common web application and infrastructure vulnerabilities, risks, and appropriate countermeasures.
• Work closely with security teams to identify and remediate security issues.
• Maintain confidentiality of sensitive customer, business, and internal information.

• Bachelor's degree in Computer Science, Computer Engineering, Information Technology, or a related field preferred. Equivalent relevant experience may be considered.
• Strong hands-on experience administering Linux servers, preferably RHEL, Ubuntu, and/or CentOS.
• Strong troubleshooting and analytical skills with the ability to independently research and resolve complex technical issues.
• Experience with Linux system administration, configuration, patching, and security.
• Knowledge of Windows Server administration and core services.
• Familiarity with VMware vSphere/ESXi.
• Knowledge of web/application server technologies such as Apache and Nginx.
• Understanding of server and web application security principles.
• Ability to manage multiple priorities and meet project deadlines.
• Strong written and verbal communication skills.
• Ability to collaborate effectively with technical and non-technical stakeholders.
• Ability to work independently as well as part of a broader IT team.
• Willingness to participate in an on-call rotation.

• Experience with OpenShift, Kubernetes, and/or Docker.
• Experience installing, configuring, upgrading, monitoring, and troubleshooting OpenShift/Kubernetes clusters.
• Familiarity with CI/CD pipelines, Git, and DevOps practices.
• Experience with Infrastructure as Code (IaC) tools such as Terraform and Ansible.
• Experience with monitoring and logging platforms such as Prometheus, Grafana, ELK, or Splunk.
• Familiarity with Linux security hardening and patch management.
• Certifications such as RHCSA, RHCE, CKA, CKAD, or OpenShift certifications are a plus.

We are looking for someone who is technically strong, security-conscious, and comfortable working across Linux infrastructure, virtualization, and modern containerized environments.

The ideal candidate should be proactive, capable of handling complex production issues, and able to collaborate effectively across IT, DevOps, development, and security teams.

ISHIR is a digital innovation and enterprise AI services provider.

We work with startups and enterprises to shape the future through accelerated innovation, deep technical expertise, access to global digital talent and a passion for complex problem-solving.

With our help, our clients overcome their most difficult digital challenges leveraging AI.

We are not just consultants, we are partners in our clients’ success, assisting them with re(gaining) competitive edge by identifying opportunities for differentiation, industry disruption, scalable innovation, and go-to-market strategies that deliver successful outcomes.

At ISHIR, we help bold businesses accelerate innovation through Talent, Speed-to-Market, and AI.

We help make an impact by solving real problems using innovation, improved customer experiences and the right technologies.

As an ISHIR employee, you will get the advanced training you need to be successful, and the opportunity to apply it.

You must be passionate about technology, crave responsibility, and be eager to apply your knowledge to real business solutions for our startup and enterprise customers.

These are the qualities of a person destined for success at ISHIR.

ISHIR attracts a special type of individual—someone who is proactive, thrives on challenges, feeds off success, and looks at moving targets not as obstacles but as opportunities.

ISHIR is an exciting place to work.

It is imbued with an entrepreneurial spirit and promotes self-reliance, open communication, and collaboration.