Darryl Cauldwell

Led design and engineering team developing standardised IaaS private cloud, building on the Modern Platform foundational architecture I designed earlier. Comprehensive self-service PaaS catalogue delivering servers, databases, middleware, security, backup, DR, and NFV for defence, government, financial, and healthcare customers. Another product-on-a-product role - the key differentiator over the Managed Mid-range offering was self-service consumption with full automation and orchestration, giving customers direct control over provisioning without raising tickets.

Technical design and engineering lead for global Managed Mid-range offering. Developed highly standardised hosting platform enabling streamlined day-two operational support with flexibility for workload customisation. Built on the Modern Platform foundational building blocks, turning platform capabilities into consumable services integrated with ITSM. Essentially productising the standardised infrastructure into a managed mid-range offering with service catalogue, operational workflows, and day-two support models.

Technical lead industrialising VMware platform delivery. My first role as product manager rather than architect, introducing new skills in stakeholder management, backlog prioritisation, and agile sprints. The team adapted Agile to Scaled Agile (SAFe) for architecture and product management. Technically complex due to the scale of deployments - modular designs ensured consistent factory builds across Dell, Hitachi, and HPE hardware, with delivery workflows integrating all data centre systems.

Transitioned Global Cloud Engineering from monolithic to iterative delivery. Introduced Ansible automation for desired-state infrastructure configuration, reducing incidents and improving customer satisfaction. Drove the Ansible adoption strategy across Global Cloud Engineering, evangelising automation to replace ad-hoc scripting with standardised playbook development. Infrastructure code moved into Atlassian source control with code review workflows, establishing repeatable and auditable delivery practices.

Architected and automated AWS-based Managed Public Cloud offering with centralised management, billing, monitoring, and security via ServiceNow. Primarily focused on Ansible automation for infrastructure provisioning and CloudFormation templates for repeatable deployments. Extensive IAM design for cross-VPC and cross-account working with federated identity. Built cost reporting for showback and chargeback to give customers billing transparency. Integrated the platform with ServiceNow for ITSM workflows and managed customer onboarding including account provisioning, baseline security, and connectivity setup.

Technical lead for site-resilient NSX solution connecting 31 remote sites via Edge Services Gateway VPN tunnels with micro-segmentation firewall rules. Designed the NSX architecture including controller cluster sizing, transport zones, and VXLAN configuration, integrated with the vSphere platform including host preparation and VTEP configuration. The solution brought together two Atos products - DDC and Enterprise Private Cloud - into a unified, site-resilient network architecture.

Designed and automated private cloud infrastructure using hyper-converged VMware SDDC. Showcased how automation enables rapid, consistent provisioning - reducing time to production and freeing teams from manual infrastructure work. This was essentially building a VMware SDDC stack - the pattern that later became VCF - but before VCF existed. Ansible automation handled the full SDDC provisioning - we wrote and published Ansible modules for ESXi host and vSAN management in vCenter. The arrival of VMware NSX for vSphere significantly changed the SDN automation landscape, requiring rework of the network provisioning layer. Jenkins CI pipelines provided the consumption layer for self-service delivery of servers, applications, SDN, distributed firewall, and NFV.

Transformed development workflow from static releases to continuous delivery using Service Mesh Agility Platform and Puppet. Declarative infrastructure as code replaced manual processes - delivering consistency, improved availability, lower operational costs, and faster time to value. Introduced Puppet with Razor for bare-metal provisioning and Ansible engine for desired-state configuration management. Helped write the Service Mesh Agility Platform plugin for NSX-MH, delivering layer 2 network provisioning, layer 3 routing configuration, and NSX load balancers for network function virtualisation (NFV).

Multi-petabyte storage with 99.99% availability - a significant engineering challenge. Evaluated EMC VMAX and Hitachi VSP, led consolidation to unified Hitachi VSP. Hard work paid off - major cost savings, performance improvements, virtualised LUNs enabling data mobility, and improved data replication. As architect I oversaw the full delivery lifecycle. Migration planning sequenced workload moves with minimal downtime windows, with risk management and rollback plans for each wave. Redesigned host presentation including fibre channel zoning, multipathing policies, and HBA firmware. Implemented SRDF for disaster recovery replication on the new platform. Managed decommissioning of legacy EMC arrays and provided stakeholder reporting to programme board tracking progress and cost savings.

Designed, engineered, and delivered a vSphere hosting platform for global systems management tooling. The monitoring platform required a higher SLA than the services it monitored to ensure contractual reporting obligations were met. Designed with dedicated infrastructure isolated from customer workloads to avoid shared-fate failures, strict high availability with vSphere HA admission control policies, and robust backup and DR to protect historical monitoring data as contractual evidence.

Building on decomposing monolithic applications into delivery units, this role focused on increasing velocity from code to production. Developed stateless application deployment using VHD detachment/attachment with PowerShell, NetApp snapshots, and VMware. Not a CI pipeline yet, but the forerunner to streamlined delivery with governance and control. Worked very closely with the application software architecture team as the infrastructure architect, designing a joined-up end-to-end solution that coupled best-of-breed infrastructure technology with an innovative approach to software delivery. Breaking the monolith into independently deployable units was ahead of its time - a pattern that has since become mainstream with microservices architecture.

Technical lead for vCloud Director self-service IaaS on VCE vBlock for hospital trust. Introducing multi-tenancy enabled better use of assets through increased resource sharing with guarantees - applications functioned as required. Built on VCE vBlock converged infrastructure - Cisco UCS blades, EMC storage, and Cisco Nexus networking. Configured vCloud Director with organisations, virtual datacentres, catalogs, and vApp templates. Network pools provided tenant isolation, with vShield Edge delivering NAT, firewall, DHCP, and VPN per tenant. Resource allocation models and vCenter Chargeback Manager enabled cost transparency. Curated VM catalogs gave hospital trust teams self-service provisioning without raising tickets. Designed to meet NHS IG Toolkit compliance and data separation requirements for patient data, with operational handover and training for the new self-service model.

Designed and led vCloud Director self-service IaaS implementation for Nordics region, collaborating with local delivery engineers. Multi-tenancy enabled better asset utilisation through resource sharing with guarantees, ensuring applications performed as required. Building on the proven vCloud Director architecture from the healthcare project, adapted the design for Nordic regional requirements. Worked onsite with local delivery engineers, addressing data sovereignty considerations across Nordic countries. Created documentation and knowledge transfer to enable local teams to own and operate the platform independently - proving the architecture was repeatable across regions.

Hardware technology refresh - led rearchitecting the VMware hosting solution for more robust scale and DR capability. Innovative NetApp partnership enabled transglobal data replication. Complemented by decomposing a monolithic application into smaller, independently shippable delivery units. Central to this was migrating storage to NetApp across the UK and Chennai sites, with SnapMirror replication enabling transglobal data mobility. NetApp snapshots provided disaster recovery capability and enabled reporting data to be split from OLTP databases - removing analytical workloads from production. The database tier ran on massive HPE Itanium SuperDome IA64 systems, making certification and validation particularly complex. Upgraded through vSphere 4.x to 5.0, implementing HA and DRS clustering for availability and load balancing. VMware SRM automated DR failover between sites. NetApp ONTAP configuration included deduplication, thin provisioning, and FlexClone for dev/test copies. VMware Update Manager handled ESXi patching at scale. Performance baselining validated the redesign with before/after metrics, and capacity planning drove consolidation ratios and VM right-sizing. N+1 resilience design ensured host and chassis failures wouldn't impact patient-facing systems. Application dependency mapping, change management for zero-downtime migration of production healthcare workloads, and vendor coordination across NetApp, HPE, and VMware.

Architect for UK Government Identity and Passport Services. Security, identity access management, and regulatory compliance were paramount. Gathered requirements, designed and implemented a VMware virtual hosting solution with extensive automation enabling several hundred developers and testers to rapidly spin up environments. Platform was vSphere 4.0, designed to meet government IL3/IL4 security accreditation with CESG guidance. Strict network segregation with VLAN isolation, separate Active Directory forests for security boundaries, and hardened builds to government security baselines. Role-based access control in vCenter with audit logging, and encryption for data at rest and in transit to protect sensitive personal data. Produced RMADS security documentation for accreditation.

Consistency was the goal - dev and test environments that matched production to reduce issues when shipping code. Created automation spanning infrastructure configuration, application deployment, configuration, and lifecycle management through Altiris. This was my first role as VMware architect - designed the full stack including HPE blade chassis and storage array to build a VI3 hosting platform for the development and test environments. Managed the platform through VirtualCenter, designed Fibre Channel SAN with VMFS datastores and multipathing, and implemented VMware Consolidated Backup (VCB). Capacity management ensured the platform was right-sized as demand grew. Based in Chennai where I recruited and trained the local engineering and operations teams, which grew to 114 engineers and managers at peak. In Chennai, created runbooks and operational documentation for knowledge transfer, completed ITIL service transition from project to BAU operations, and established monitoring via HP Operations Manager.

Deployed nationally sensitive IT infrastructure at the VFS Global Visa Application Centre in Belgrade - the primary location for UK visa applications in Serbia, handling document scanning and biometric data collection. VACs were located on industrial estates to protect embassies, so the system required robust and reliable communications back to embassy systems over distance.

Built imperative automation using modular Altiris scripts to deliver 4,500 servers across multiple data centres. The governance and control this introduced simplified deployment at scale and made day-two operations manageable. The platform became Veritas's largest worldwide deployment of Veritas Cluster Services (VCS) - a unique disaster recovery solution for both databases and VMs - and the largest Citrix solution globally at the time. Pre-API era, automation relied on scripting with VBScript, batch files, and WMI for remote Windows configuration. Bare-metal blade provisioning used HP Rapid Deployment Pack integrated with Altiris for PXE boot and scripted OS installs across HP BladeSystem c-Class infrastructure. SAN provisioning included LUN masking, zoning, and fibre channel configuration. Early adoption of VMware ESX 2 with MUI management interface marked the start of virtualisation in the environment. Automated creation of cookie-cutter training environments by scripting VMX files and cloning VMDK files to produce isolated instances of iSoft clinical applications. Each environment ran dual-homed Windows servers with self-contained Active Directory and supporting services on overlapping address spaces - enabling train-the-trainer programmes that scaled hospital staff onboarding. These isolated, repeatable environments were a game changer for the programme.

Operational acceptance testing at massive scale - DWP serves 20 million citizens across 800+ locations with one of Europe's largest IT estates. Packaged and tested application deployments using Radia Client Automation (RCA) for the Digital Office Infrastructure program. Responsibilities included MSI application packaging, conflict testing to ensure new applications didn't break the standard desktop image, Group Policy configuration validation, regression testing of patches against the full application catalogue, and Citrix thin client testing for branch offices. Work followed strict ITIL change management with detailed test scripts and evidence packs, alongside security hardening validation for government baselines.

Introduced me to financial services. Engineered secure web hosting for a customer-facing mortgage application and approvals system on IIS. Learned sophisticated business logic and dynamic PDF generation - understanding how technology underpins complex financial workflows. Platform was Windows Server 2003 with IIS performance tuning including thread pools, caching, and response time optimisation for customer experience. Role followed independent travel in Peru and Bolivia.

Operating Royal Mail's public-facing internet infrastructure - business-critical IIS, DNS, and Squid proxy services. Internet services were a rapidly growing area of business value for Royal Mail, and this role was a natural progression into that space. Managed public-facing infrastructure for royalmail.com, Parcelforce, and group brands - massive scale for the time. Security included DMZ architecture with CheckPoint Firewall-1 and SSL. My work here led to joining the 'Change of Address' team, among the first in the UK to embrace Agile. Learned middleware technologies including IBM WebSphere MQ, WebSphere, and SAP ERP. The .NET web service was the Change of Address application - a broker that processed address change requests and propagated updates across multiple government record systems. The Agile approach included Scrum practices and peer programming, predating the widespread adoption of terms like XP.

Moved from deploying applications in the field to validating them in the lab. Tested end-to-end server and network solutions, working with R&D on pre-production Compaq hardware. Having seen deployment challenges firsthand, I could now identify issues before they reached scale - and started influencing developers to design for day-two operations. Key activities included load and stress testing with LoadRunner to simulate production-scale traffic, compatibility testing against the existing estate, network infrastructure and WAN testing between sites, disaster recovery and failover validation, and capacity planning to size hardware for production workloads. Wrote test plans and acceptance criteria as release gates, with defect tracking back to development teams. Evaluated Windows 2000 and Active Directory migration paths from NT 4.0.

Nationwide deployment team for enterprise applications using central servers and thick clients. Delivered Esri GIS for postman walk route planning with custom in-house extensions. The layered software dependencies required careful lifecycle management. Engineering upgrades from NT 3.51 to NT 4.0 across the estate. Responsibilities included domain architecture with Primary and Backup Domain Controllers, WINS, DNS and DHCP configuration, logon scripts, roaming profiles, system policies, tape backup routines, and service pack rollouts. SMS replaced floppy-disk based distribution for remote software deployment.

Covered desk side support across the south central region. Based at Reading sorting office where regional application servers were hosted, giving me my first hands-on server administration experience. Day-to-day work included floppy-disk based software distribution, printer setup, hardware upgrades, and early office suite and email rollouts. Key projects included lifecycle upgrades from Windows 3.0 to 3.1 to add TCP/IP networking, enabling Windows NT domain connectivity.

Component-level electronic repair and logistics for NCR towers, analogue mobile phones, modems, and Symbol Technologies barcode scanners. Fault diagnosis involved swapping out individual components on circuit boards rather than whole-unit replacement. Built my first database - a Microsoft Access system for tracking inventory by serial number and device movements. This role introduced me to managing firmware and software updates at scale.