Eliseo Bueloha
Welwyn Garden City,Hertfordshire
Summary
Proactive Senior IT System Administrator with 14 years of experience across Linux system administration and computer networking. Skilled in optimising performance and enhancing security for complex IT infrastructures. Demonstrates strong problem-solving abilities and effective communication, driving successful project outcomes through teamwork. Committed to continuous learning and adapting to evolving technologies in fast-paced environments.
Overview
2
2
Languages
1
1
Certification
15
15
years of professional experience
Work History
Senior IT Sys Admin – Production, Low Latency Fintech
Celoxica
04.2024 - Current
- Linux System Administrator (RHEL9, Oracle Linux, Debian, Rocky)
- Cisco Networking, AWS, Kernel Patching, Onload Kernel by pass
- Server Tuning for Low Latency.
- IPMI Tool, Ethtool
- High-Performance Networking (Musticast)
- Rx Ring buffer - Kernel Processing incoming TCP/ UDP Packets
- TX Ring buffer - Kernel Outgoing TCP/UDP Packets
- fork () / System calls
- Senior Network Engineer (CCNP)
- BGP, OSPF, EIGRP, GRE, Data centre, Corporate Network, Access Point, WiFi, Active Directory, MPLS,
- Knowledge of Programming in C standard Libraries, with fork process API system calls, pthread, pointers, C++ Object Oriented Programming, Sockets, File Management, and Python
- Good knowledge of Bash scripting
- Storage with: VG groups, LVM, fdisk /dev/sdx, EXT4, EXT2, mkfs.ext2,ext4 file systems FAT, NTFS MBR, GPT
- User Account Management
- NMCLI
- Grub_CMD_Line for Kernel Parameters
- Huge Pages
- Page Caching
- Low level file management using system calls, ltrace, strace
- SFTP, DNS, DHCP, AWS, Terraform
- Unix User Management
- Huge Pages for virtual Memory Management
- Memory Cache
- /proc/sys/vm/drop_caches
- Lsmod, modprobe, Kernel Headers & Kernel Devel.
- /etc/security/limits.conf
- Raid 5, Raid 1, RAID0
- mdstat
- Volume Group
- Logical Volume
- On-prem Server Migration
- Knowledge of OS Build, network PXE and cloning using Clonezilla or dd command
- Linux server migration
- Security Audit
- Servers: HPE, Dell, Ciara/ American Megatrend
- Development tools, Python, Xconnect, GRE tunnels, BGP, VLANs, RPM, Yum repo list, yum subscription Manager Solarflare, FPGA, PTP, SFPTPD
- Wireshark, MySQL Database, Nftables / IP tables, Server-side security
- Systemd automation, Journalctl, OTP Authentication, SOPHOS VPN, server VLANs, patching schedules, ticketing, internal intranet, UAT, Prod, SFTP, SSH rsa.pub, GIT, Bare Metal Server cloning, Cisco Switch configuration, DHCP, DNS, Linux User account Management, Red Hat-Volume-groups management, Linux Server Migration, grub HPE ilo, Ethtool, IPMI tool, Dell Open Manage, RAID5, RAID1, numactl, Nginx, BIOS, UEFI, Hyper Tech Ciara, American Megatrend, Data Center.
- Server shipping to Co-location, EC3, EC2
- Celoxica offers the fastest trading & market data solutions with the lowest footprint. Their solutions include market data feed handlers for the US and European Equities, Options, Futures exchanges and FX. The services are designed to offer ultra-low latency measured in single-digit microseconds and ultra-high throughput, together with accelerated Market Data, Market Access and in-Line Risk.
IT Associate - Production
Method Investment and Advisory
07.2022 - 03.2024
- Linux System Engineer (RHEL, Alpine Linux, Alma Linux, Clear Linux, Rocky Linux, Oracle Linux, Centos, Ubuntu, Debian 11)
- Computer and Network Security
- Cisco Networking, Routers Switches(Layer2, Layer3, firewalls)
- DMZ, NAT, Access-list, PAT, Etherchannels, Multicast, UDP, Router on a stick
- Managed user space Linux systems, including DNS, DHCP, GRE/IPsec, and multicast configurations.
- AWS, OVH Hosting, Provisioning VM, Accessing VMs from KVM
- Virtualization (ESXi) and Microsoft Servers, Vcentre VMware, Provisioning Hardware, Data Center
- Docker, Networking Switches, OSPF, BGP
- Web application Delivery (DevOps)
- Automated system processes using systemd services and timers; implemented SSH key management and SFTP; developed scripts in Bash, Python, and C++.
- Programming, C++, Python, JavaScript, HTML, CSS, MySQL
- Nginx, Postma Collector, Insomnia, Kernel bypass Onload Solarflare
- Configured IP routing protocols to optimise data flow; utilised GIT for version control.
- Bullseye, SSH, SFTP, Kernel and Posix API system calls, Hardware, Data Centre
- Onload Solarflare, SFP
- Some basic knowledge of Kernel bypass with Solarflare open onload
- Documentation with Confluence.
- Founded in 2001 by a team of professionals specialised in capital markets and asset management with offices in London and Milan.
IT Engineer
Skechers USA
02.2018 - 06.2022
- Linux system Administrator & Devops:
- Managed processes, disk space, and memory for docker containers. Configured Apache web services and nginx, optimised server performance by enabling and disabling unnecessary Apache modules, and automated MySQL database backups with SSL and API for certificate validation (Let's Encrypt).
- OS installation and configuration. LAMP server installation and configuration, BASH scripting and script researching, cronjob, automation with Ansible’s /etc/ansible.host.conf files, script and .ansible-playbook .Yaml.
- Acquired basic skills in AWS cloud management., Docker containers && Ansible Node with Yaml
- Configured, designed, and implemented Cisco routers and switches, including HSRP, EIGRP, OSPF, BGP, GRE/IPSec VPN, VLANs, NAT, and access-lists, while maintaining network documentation and monitoring with Syslog.
- Gained experience in configuring Cisco networking devices.
- Managed ESXi virtualisation environments effectively.
- Creating new virtual machines, browsing the ISO folder to select the target Operating system, installation of operating system and packet update, increasing resources of VMs, Decommissioning VMs, updating ESXi firmware, renewing licencing, working with V-center to move VM from one host to another
- Developed foundational skills in managing Microsoft Servers and Office 365.
- Installation and configuration of Microsoft Active Directory, Creating Group Policy and Organisation Unit, assigning policy to OU containers, creating users account in AD, updating user password, email office 365 and groups.
- Installed workstations and coordinated setup of desks and telephones, ensuring user readiness and efficient onboarding.
- Skechers is a Fortune 500 company that designs, develops, and markets a diverse product portfolio of lifestyle and performance footwear, apparel and accessories for men, women and children around the globe.
IT Engineer
Media Communications Group PLC
02.2013 - 08.2017
- Configured and implemented Cisco routers and switches, including HSRP, EIGRP, OSPF, BGP, GRE/IP Sec VPN, VLANs, NAT, access-lists, IPSLA, VTP, EtherChannel, IPV6, DHCP servers, and radius servers, while monitoring with Syslog. Installed hardware and software, and managed Avaya telephone systems with PBX and user management.
- Cisco Networking
- Implemented ESXi virtualization solutions to optimise server resources.
- Creation of new virtual machines, browsing the ISO folder to select the target Operating system, installation of operating system and packet and licensing update, increasing resources of VMs, Decommissioning VMs, updating ESXi firmware, working with V-centre to move VMs from one host
DevOps Engineer
Fantasia Advertisement
12.2011 - 01.2013
- Used Docker and Kubernetes to manage, scale and update containers for improved automation possibilities.
- Used CI and CD automation testing to effectively assess application function and user experiences.
- Managed version control systems like Git, ensuring streamlined code integration and collaboration amongst team members.
- Apache2 and web server configuration, HTML, JavaScript, Flash and Action Script, BASH scripting, Managed SSH key generation and deployment Checking Monitored Apache2 web server performance to ensure optimal uptime, Set up and managed MySQL database configurations and backup, and Disabled unnecessary services on Apache, improving overall security posture, Created SSL certificates to secure web communications and Integrated external API for certificate validation with Let's Encrypt, enhancing secure web communications
Education
Certificate - Computer Networks Professional
London Metropolitan University
London01-2016
MSc - Electronics Communication and Computer Networks
University of Westminster
London01-2010
BSc - Computer Science
University of Westminster
London01-2008
Electronics Communications - Human Computer Interaction with Artificial Intelligence Design
University of Cambridge (Department of Engineering)
London, ENGSkills
- Networking & Routing
- Computer Networks
- IPv4
- IPV6
- NAT
- DHCP
- Access list
- Route Maps
- GRE Tunnels
- Basic MPLS
- IPSLA
- BGP
- OSPF
- Rip
- Static and Dynamic Routing
- Fortinet
- Cisco
- Cisco Technologies
- Cisco Network Professional
- Routing
- Switching
- Firewall
- Data centre
- Security
- Cisco Routers
- Cisco Switches
- Layer 2
- Layer 3
- Network Monitoring & Tools
- Wireshark
- SolarWinds
- Zabbix
- Linux & System Administration
- Linux System Administration
- RHEL
- Red Hat Enterprise Linux
- Debian
- Ubuntu
- Oracle Linux
- Rocky Linux
- RHEL Satellite
- IPMI
- ETHtool
- Bash Scripting
- On load Kernel bypass
- NMCLI
- Terra
- Ansible
- User Migration
- OTP authentication
- SSH
- Authd
- Nginx
- Apache
- System tuning
- Selinux
- Modprobe driver management
- VLAN
- SSH key management
- RPM
- Make
- Server tuning
- Grub
- Root password recovery
- Huge Pages
- Memory Cache
- User Management
- Kernel Development
- Buildroot
- Yokto
- Package Management
- Yum
- Dnf
- Apt
- Dpkg
- Rpm
- apk
- Brew
- Web
- Apache2 Web Server
- Mysql
- PHP
- Reverse Proxy
- VSFTPD
- PTPD
- Nginx load balancer
- System Management
- Group Management
- File Permission
- File Ownership
- System profile
- Systemd
- System Timers
- Cloud
- DevOps
- Automation
Custom
London
Languages
Spanish, English
First Language
French
Intermediate
B1
Certification
- Unix System Engineer
- Cisco Certified Network Professional
- Web Programming with visual Communications
- Kernel Programming / Systems Developer
- AWS
- Data Center
- MSc Electronics Communications
- Human Computer Interaction with Artificial Intelligence (University of Cambridge)
Interests
- Travelling
- Football (European)
- Programming
- Tech enthusiast
- Arificial Intelliengence
- Human kind
- Spending time with my children
Proxmox, Vmware, System tuning, Onload Kernel Bypass
Professional Experience
Senior Infrastructure & Performance Engineer | Celoxica | 2024
Proxmox,VE, Vmware: Engineered high-availability clusters with Ceph hyperconverged storage.
- Proxmox VE: Migrated 50+ legacy workloads seamlessly into Proxmox environments.
- VMware vSphere: Managed enterprise vCenter infrastructures spanning multiple global datacenters.
- VMware vSphere: Optimized DRS and HA policies to guarantee 99.99% uptime.
- System Tuning: Adjusted Linux kernel parameters (sysctl, hugepages) for low-latency workloads.
- System Tuning: Configured CPU pinning, NUMA boundaries, and power management profiles.
- Onload Kernel Bypass: Deployed Solarflare/AMD OpenOnload to accelerate high-frequency trading applications.
- Onload Kernel Bypass: Slashed network latency by 40% using TCP/UDP bypass techniques. [1, 2, 3, 4]
Core Competencies
- Virtualisation: Proxmox VE (PVE), VMware vSphere ESXi, vCenter, KVM.
- Performance Tuning: Kernel optimization, BIOS/UEFI tuning, interrupt handling, NUMA isolation.
- Low-Latency Networking: Solarflare OpenOnload, EF_VI, DPDK, SR-IOV.
- Storage & Clustering: Ceph, vSAN, ZFS, iSCSI, Fibre Channel. [1, 2, 3]
Technical Projects
Ultra-Low Latency Trading Infrastructure
- Objective: Minimise end-to-end packet processing time for financial data feeds.
- Action: Configured bare-metal and virtual servers with Solarflare network cards and OpenOnload.
- Action: Applied advanced system tuning including CPU isolation (isolcpus) and disabling C-states.
- Result: Achieved sub-microsecond network latencies and eliminated kernel-space context switching overhead.
Hypervisor Modernisation & Consolidation
- Objective: Reduce licensing costs and improve resource utilization.
- Action: Built a multi-node Proxmox VE cluster integrated with ZFS and Ceph storage.
- Action: Migrated mission-critical workloads from VMware ESXi using automated scripting.
- Result: Cut infrastructure overhead costs by 35% while maintaining strict performance SLAs.
Timeline
Senior IT Sys Admin – Production, Low Latency Fintech
Celoxica
04.2024 - Current
IT Associate - Production
Method Investment and Advisory
07.2022 - 03.2024
IT Engineer
Skechers USA
02.2018 - 06.2022
IT Engineer
Media Communications Group PLC
02.2013 - 08.2017
DevOps Engineer
Fantasia Advertisement
12.2011 - 01.2013
Certificate - Computer Networks Professional
London Metropolitan University
MSc - Electronics Communication and Computer Networks
University of Westminster
BSc - Computer Science
University of Westminster
Electronics Communications - Human Computer Interaction with Artificial Intelligence Design
University of Cambridge (Department of Engineering)