Aleksandar Zivanovic, Systems Developer in London, United Kingdom
Aleksandar Zivanovic

Systems Developer in London, United Kingdom

Member since April 11, 2018
Alex is a DevOps engineer with 10 years of experience and deep expertise in Linux and related technologies. In the software space, he has been a developer, tester, and automation engineer. In the systems space, he has been a systems engineer and a network engineer. With a wide range of experiences in both worlds, he provides multiple services for data center support, internal and external cloud operations, and DevOps engineering.
Aleksandar is now available for hire

Portfolio

Experience

Location

London, United Kingdom

Availability

Part-time

Preferred Environment

Bash, Python, Java, Linux

The most amazing...

...project I've done was integrating stock exchange high-frequency trading software and post-trade derivative analytics for one of the largest UK banks.

Employment

  • Systems and Network Engineer

    2019 - 2020
    Utility Warehouse (UW)
    • Contributed to the internal systems projects for Telecom Plus (branded as UW), including networks, telephony, databases, virtualization, operating systems, and software components.
    • Implemented Grafana BGP monitoring through a sFlow Prometheus exporter connected to Cisco Nexus.
    • Deployed Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) for a batch of domains.
    • Implemented Prometheus SNMP Exporter for several edge devices.
    • Improved data center operations such as repatching systems, physical chassis, virtual machines, network devices, and reconfiguring virtual LANs (VLANs).
    • Implemented HDMI over an IP network and deployed it on 12 floors. The signal for the new centralized system runs through this isolated parallel network.
    • Migrated system components from the on-premise data center to AWS cloud.
    • Implemented internal DC subnets peering with Amazon AWS VPCs.
    Technologies: SNMP, Prometheus, Kubernetes, Docker, Python, Bash, Linux, Cisco
  • Systems Engineer

    2017 - 2019
    Ticketmaster International
    • Administered Ticketmaster's entire infrastructure containing more than 30,000 servers.
    • Served as a Linux administrator, setting up systems, resolving system bugs reported by the developers, and automating processes.
    • Supported the business during Black Friday sales events.
    • Administered NetApp storage (series 6-9) and fine-tuned the Network File System (NFS).
    • Configured Citrix NetScaler devices, VIP health checks, monitors, and SSL offloading.
    • Contributed to Bash scripting of Linux boxes for database exporting and importing and syncing with storage systems.
    • Administered the system's bare-metal and private cloud portions in the public cloud and AWS, which included Terraform scripting, Docker imaging, ELK, Prometheus, and GitLab CI.
    • Refactored old reporting software to Chef-based software, using infrastructure as code (IaC).
    • Migrated to AWS and designed architecture diagrams and system flows.
    Technologies: Amazon Web Services (AWS), NetApp, Citrix NetScaler, Rsyslog, Prometheus, AWS, Bash, Chef, Linux
  • Linux Release Engineer

    2015 - 2017
    Sungard/FIS
    • Collaborated with the development team on NextGen high-frequency trading (HFT) and post-trade derivative analytics software.
    • Wrote build and deploy steps and procedures for a CI/CD chain in Bash and Python.
    • Optimized build times by rewriting build scripts and implementing parallelization on multiple build agents.
    • Implemented additional stages to build pipelines using JaCoCo, SonarQube, and Veracode to improve code quality.
    • Assisted financial industry clients—including BBVA, Lloyds, and Deutsche Bankand—and their IT teams with integrations.
    • Placed application modules in Docker containers, from front-end to in-memory database and storage components, and refactored application architectures.
    • Migrated several components from AWS to in-house servers and from in-house servers (e.g., build servers) to AWS.
    Technologies: Bash, Docker, JUnit, Bamboo, Atlassian, Maven, Java, Linux
  • Software Engineer

    2013 - 2015
    PSTech – Adobe Systems
    • Worked on Adobe Connect 9 and 10 projects for three years.
    • Wrote several AMT releases in Core Java for the Adobe Connect migration tool for a development project focused on migrating Adobe Connect from on-premises to cloud-cluster premises.
    • Fixed bugs in a partially working AWS provisioning controller in Ruby on Rails for Adobe Connect products. This controller was used as an in-house solution for a provisioning tool, similar to Terraform or AWS CloudFormations used in the present.
    • Wrote several hundred tests for Adobe Connect products using automation testing in Selenium and in-house frameworks. Integrated testing, building, reporting, and analyzing metrics for the application builds in Jenkins with Ant, JUnit, and Groovy, among others.
    • Deployed ACMS Adobe Connect to AWS cloud on every release.
    Technologies: Microsoft SQL Server, Jenkins, Ant, Selenium, Ruby, Java
  • Systems Engineer

    2012 - 2013
    Alteatec
    • Administered general Linux-based servers for the gaming industry, the largest portal of which was EuroSlots, along with many small projects.
    • Configured Cisco ASA devices, access-list (ACL) rules, data center equipment switches, and VLANs.
    • Installed local Blade servers in the Belgrade branch office.
    • Recovered out-of-sync MySQL clusters in production environments.
    • Set up several system components—for example, consumer betting results in the early AWS phases as prototypes for future development.
    Technologies: ZeroMQ, MySQL, Python, Java, Jenkins, Cisco, Linux
  • Network Engineer

    2011 - 2012
    Halkbank
    • Served as a network engineer in a Halkbank disaster recovery (DR) data center in Serbia that was also in charge of four nearby network branches.
    • Provided data center support in server rooms and interventions on physical network devices.
    • Configured Cisco devices, VLANs, removals, and basic L2 and L3 actions.
    • Provided hardware and software support for local bank network branches.
    • Configured Avaya telephony systems, access, and trunk links and connected branch offices to the primary and DR data centers.
    • Monitored and troubleshot bottlenecks in network traffic over sFlow and NetFlow systems.
    Technologies: Nagios, Squid, Linux, Cisco

Experience

  • Multiple Roles in Adobe Connect Projects

    Account Migration Tool (AMT) Project (Core Java): I was a developer on an AMT ETL tool used to transform database schemas and migrate all the client data to the newer versions of the product. It was an ETL tool with the addition of forking the destination to various product flavors (virtual hosted, clustered, and on-premise). We deployed several successful releases over nine months of the contract.

    Adobe Connect Managed Services (ACMC) Project: I was a DevOps developer on a Houston controller written in Ruby, working to reflect rapid changes on the Amazon AWS API side. The controller was used to provision Adobe Connect to AWS cloud. It was similar to how Terraform is used today, with a proprietary source designed only for the Adobe Connect AWS infrastructure. I maintained Cygwin shell scripts and batch scripts inside AMIs and wrote new scripts for operating system actions such as upgrades and syncs. I migrated customer environments to new clusters by deploying rolling release strategies.

    Adobe Connect Project: as a software quality engineer for 18 months, I wrote and executed manual test cases and wrote Java-based automation tests for the new application features, using a Jenkins CI setup.

  • Sungard NextGen HFT and Post-trade Derivatives Platform

    I was a member of the six-person DevOps team that focused primarily on infrastructure and build processes, CI/CD pipelines, and CI/CD improvements in every sprint with features like build plans, deploy plans, testing pyramids, gates, Veracode, SonarQube scans, JaCoCo code coverage, and AppDynamics code.

    In addition, we were tasked with server architecture and code deployment automation, maintenance, monitoring, virtualization, and orchestration, using the latest technologies like Docker, Swarm, and Rancher. We managed the basic Atlassian sysadmin product line, including Bamboo CI server, Jira, Stash, Confluence, and Crowd, as well as administration of the virtual machine infrastructure over VMware vSphere in multiple data centers in three locations.

    We refactored infrastructure from VM code-based to Docker-container orchestrated and severed configurations automation with Ansible. We performed classic Linux server administration and troubleshooting and optimized environments for the NextGen application. Finally, we integrated build plans with deploy procedures for continuous delivery pipelines for various customers.

  • Ticketmaster International Linux TechOps Team

    I was a TechOps and DevOps engineer in a five-person team called international operations and reliability (IOPS-REPORTS). The team covers five products, mostly in the reporting sector, that process a large number of records, store them in various database engines, and perform transformations through BI tools. All the teams we communicated with daily were T-shaped with full-stack engineers.

    The scope of technologies used was vast:
    • Old projects ran on bare-metal servers with Sybase and an old, in-house Perl configuration management system called Rubix
    • Bash scripting over systems that ran virtualized on Citrix XenServer pools and used Oracle databases, NetApp shared storage, and Citrix NetScaler software and hardware load balancers with various software on the systems, from Python over Java to .NET
    • The newest public and private cloud projects on CloudStack and Amazon AWS with Docker containers and Chef and Ansible configuration management, built with GitLab CI and deployed to AWS with Terraform

    We refactored one system at a time, making it IaC with CloudStack, Docker, and Chef technologies for the internal cloud and Terraform and Docker for the external cloud projects.

  • Palo Alto IP Parser for Whitelisting AWS Ranges
    https://github.com/mra19c/PaloAltoIPparser.git

    This is a Python Flask-based web server in a uWSGI container that fetches Amazon AWS IP ranges and exports them in the server's root as a text file. Since Palo Alto firewalls can fetch HTTP resources and resources from the local file system, this was one of the solutions to refresh Palo Alto ranges.

  • HPE Integrated Lights Out (iLO) Metrics Exporter for Prometheus
    https://github.com/mra19c/ilo-exporter.git

    I improved the Hewlett Packard Enterprise (HPE) iLO exporter that monitors various parameters of HP Blade hardware in enterprise data centers. It's instrumental in integrating these metrics with other metrics in your Grafana set.

Skills

  • Languages

    Bash Script, Python, Java, SQL, Ruby, C, Bash
  • Tools

    GitLab CI/CD, Citrix NetScaler, Apache, Terraform, GitLab, Logging, Jenkins, VPN, Docker Swarm, Chef, Ansible, Amazon Virtual Private Cloud (VPC), Git, ELK (Elastic Stack), Rsyslog, Maven, Exim4, Postfix, Nginx, Apache JMeter, Apache Maven, Apache Ant, Atlassian, Bamboo, Squid, Nagios, Grafana
  • Paradigms

    DevOps, Continuous Deployment, Continuous Delivery (CD), Automation, Test Automation, Continuous Integration (CI), Cisco Certified Network Associate Routing & Switching, Microservices Architecture, Microservices, Penetration Testing, Web Architecture
  • Platforms

    Linux, Docker, XenServer, Red Hat Linux, Linux CentOS 7, Amazon Web Services (AWS), Kubernetes, CentOS
  • Other

    Cisco, AWS, Systems Engineering, System Administration, Linux Administration, SSH, Servers, HAProxy, Virtualization, Continuous Monitoring, Heartbeat, Infrastructure, Cloud Infrastructure, Infrastructure as Code (IaC), Server Infrastructure, Immutable Infrastructure, Server Security, Enterprise Systems, Enterprise Design, Enterprise Architecture, Security Analysis, Private Clouds, Monitoring, Hypervisors, Virtual Machines, Firewalls, ASA Firewalls, VMware ESXi, Cryptography, Prometheus, API Testing, Ant, BGP, HSRP, VLAN 802.1q, Architecture, Hybrid Cloud Infrastructure, Security Design, HttpUnit, Espresso, SNMP, Computer Engineering
  • Frameworks

    JUnit, Selenium, Flask
  • Storage

    NetApp, MySQL, Dell Blades, HP BladeSystem, Data Centers, PostgreSQL, MySQL Clustering, Microsoft SQL Server
  • Industry Expertise

    Security
  • Libraries/APIs

    Jenkins Job DSL, JaCoCo

Education

  • Bachelor's Degree (Hons) in Computer Engineering
    2005 - 2011
    School of Computing - Belgrade, Serbia

Certifications

  • Cisco Certified Network Associate (CCNA)
    JULY 2012 - JULY 2015
    Cisco Systems

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