Lead Infrastructure Engineer

Key Responsibilities Mainframe modernization enablement Partner with application and platform teams to migrate and modernize mainframe-adjacent workloads (e.g., rehost/refactor components, distributed integrations, data movement patterns). Design target-state infrastructure and transition architectures for Azure, including landing zones and platform services alignment. Azure infrastructure engineering Build and operate Azure core services: VNETs/subnets, routing, NSGs, Azure Firewall, Private Link, DNS, identity integrations, and resource organization (subscriptions, management groups, tagging). Implement Infrastructure as Code (IaC) using Terraform/Bicep and integrate with CI/CD pipelines. Hybrid connectivity & network performance Design, implement, and troubleshoot on-prem ↔ Azure connectivity using ExpressRoute , VPN, Virtual WAN, and hub/spoke (or vWAN) architectures. Configure and validate routing (BGP), MTU/MSS settings, latency/throughput baselines, and failover behavior. Tune connectivity performance for critical flows (batch, file transfer, API, messaging, data replication), including bandwidth planning and QoS considerations where applicable. Performance tuning & reliability Identify and remediate bottlenecks across network, compute, storage, and platform services (e.g., VM sizing, disk throughput/IOPS, load balancing behavior, TCP tuning, connection pooling implications). Establish monitoring/observability (Azure Monitor, Log Analytics, Network Watcher, Application Insights where relevant), SLOs, alerting, and runbooks. Lead root cause analysis for performance incidents and drive preventative improvements. Security, governance, and operational excellence Apply cloud security best practices (least privilege, segmentation, private endpoints, key management) and ensure alignment with governance controls. Produce clear design documentation, operational procedures, and knowledge transfer. Required Qualifications 10+ years in infrastructure engineering (cloud and/or datacenter), with direct experience supporting modernization or migration from mainframe environments to distributed/cloud platforms. Strong, practical experience with Microsoft Azure , especially: Networking (VNET, routing, NSG, Azure Firewall, Private Link, DNS) Connectivity (ExpressRoute, VPN, vWAN, hub/spoke) Compute/storage fundamentals (VMs, disk performance, availability patterns) Demonstrated ability to set up, troubleshoot, and performance-tune hybrid connectivity (latency, throughput, packet loss, MTU/MSS, routing, failover). Infrastructure as Code experience (Terraform and/or Bicep/ARM) and Git-based workflows. Strong troubleshooting skills and ability to work across teams (network, security, app, data). Preferred / Nice to Have Experience with modernization patterns: rehost, replatform, refactor; familiarity with integration with mainframe systems (e.g., batch scheduling, file transfer, messaging, data replication). Azure Landing Zone / CAF experience, policy/guardrails, and enterprise subscription design. Experience with performance tools and methods (load testing coordination, network path analysis, packet capture interpretation, baseline/SLO definition). Containers (AKS), API management, and/or messaging services (Service Bus, Event Hubs) exposure.