John Dexter Email & Phone Number

Aurora, Co, Us

Aurora, Colorado, United States

Aurora, Colorado, United States

Irving, Texas, United States

Managed multiple teams of engineers totaling as many as 30 direct reports including: Linux Platform Engineering, Unix Platform Engineering, High Performance Compute Grid EngineeringGrew the initial team from 6 employees to 20 employees in the first 18 months as manager in order to address resource capacity issues and skill gaps.Implemented Agile/Scrum methodologies within the teams to manage project workloads and forecast roadmaps.Implemented standard code contribution and release model in Bitbucket (Git) based on Gitflow branching strategy.Led initiatives for the following:OS platform CI/CD pipeline which builds and tests OS baseline releases on a nightly basis, tracks vulnerabilities, and automates Citi engineering certification processes. (Jenkins, Ansible, Podman, Hashicorp Packer, VMWare Virtualization, Confluence, Git, Python)Certify hardened OS releases based on Red Hat Enterprise Linux versions 8 and 9. (RHEL, Chef, Ansible)Development of fully automated and highly customized RHEL in-place upgrade process, which drives significant cost saving by eliminating the need to procure swing hardware and reduces the downtime required to redeploy applications. (Ansible, LEAPP, Chef, Splunk)Developed an inner-sourced OS patch automation project with a governance board consisting of multiple stakeholders and contributors from various engineering and operations teams. (Ansible, Splunk)Drive container platform adoption by simplifying the on-boarding for container developers and simplifying provisioning of developer environments. (Podman, Podman Desktop, Python, Backstage)

Irving, Texas, United States

Assisted in the design and implementation of Citi’s “Innovation Lab” project, which is a developer-focused environment where application development teams can easily build and deploy their applications in containers on top of the Red Hat Openshift platform. Innovation Lab includes a simplified onboarding process for developers, web-based IDE (Red Hat CodeReady Workspaces), CI/CD scaffolds (Jenkins), and an Openshift cluster with enough resources to deploy and test demanding workloads.Architect of the solution to centrally manage SSH trust relationships on Citi servers globally. This solution utilizes an SSH certificate authority which can sign short-lived SSH certificates. The solution also includes compliance monitoring, SSH policy governance/review processes, and dashboards to display SSH policy utilization for policy owners. (Hashicorp Vault, Ansible, Chef, Sensu, Splunk, Python)Developed Ansible playbooks to fully automate the in-place upgrade of servers from RHEL6 to RHEL7. This allowed application teams to quickly and safely upgrade their servers to a vendor-supported OS without requiring swing hardware or refactoring the application stack. (Ansible)

Irving, Tx

Team lead responsible for global operations and support of the centralized implementation of Chef within Citi. Our team maintained the global Chef infrastructure, including 27 Chef Server clusters, Chef Automate cluster, Chef Supermarket and proprietary applications, which managed more than 70,000 nodes globally (Redhat, Chef Server). Developed and maintained Chef cookbooks used during provisioning Redhat servers in Citi’s internal cloud environment (Chef, Chefspec, Inspec, Ruby).Developed automated workflows to allow System Admin teams to perform large scale vulnerability patches via Chef Cookbooks (Chef, Jenkins, Ruby).Developed Chef Cookbook CI/CD pipeline (Jenkins, BitBucket, ChefDK).Designed and developed CI/CD pipeline for Inspec compliance profiles (Chef Automate, Jenkins, Inspec, BitBucket).Defined Chef Cookbook governance model to allow safe promotion of cookbooks while integrating existing change control policies.Defined Chef Cookbook certification standards and process, to ensure internally developed cookbooks are maintained and meet evolving company standards.Defined the support model for Chef within Citi and trained Level 2 and 3 support teams.Created operations and management dashboards (Splunk, Ruby).Partnered with external teams to get them on-boarded for Chef Cookbook development and automate existing manual processes.Facilitated Chef developer community within Citi by moderating the internal social media group and hosting weekly public Chef Q&A sessions.

Dallas, Tx

Provide 2nd tier system support for enterprise applications and servers. This includes troubleshooting client database and programming issues, assisting in change management for technology enhancements, developing and improving standard business processes, and developing custom solutions for our clients' unique issues.

Underwrote Term Life, Dental and Disability insurance for small businesses (2-100 lives).

Assistant to Vice President of employee benefit sales in the southwest region of the United States (TX, OK, LA, NM, AZ, AR, UT, CO).

Part-time freelance graphic design business I started as a hobby to continue to use the skills I acquired at previous positions.

Designed and programmed several dynamic database driven websites using both ColdFusion and PHP scripting. Programmed time logging system to track hourly employees (PHP, MySQL). Implemented a data backup and recovery procedure. Created digital vector artwork primarily for screen printing on promotional products and apparel (Illustrator, Photoshop).

Designed and programmed dynamic database driven websites (ColdFusion, PHP) for the Department of Wildlife and Fisheries Sciences at Texas A&M University as well as Texas Cooperative Extension based on client specifications. Created and managed databases (Microsoft SQL Server 2000, Microsoft Access, MySQL). Setup and managed web servers (IIS, Apache). Managed user accounts and group privileges for the Wildlife and Fisheries Sciences Department.

Mba, Information Technology And Operations Management, 3.7

Activities and Societies: Beta Gamma Sigma

Bs, Economics

Minor in Business Administration