Mainframe Middleware Infra Engineer – CICS Liberty

Role: Mainframe Middleware Infra Engineer – CICS Liberty Location: London/Edinburgh Type of Job: Contract Mode of work: Hybrid -2-3 days onsite in week JD: Key Responsibilities •CICS & z/OS Systems Engineering Expertise – Individual must display deep practical experience with how CICS runs on z/OS, beyond application development. •IBM WebSphere Liberty (CICS Liberty) & Java Runtime Skills - A CICS Liberty Infrastructure Engineer must understand Liberty as a runtime and have experience in configuring the runtime •Security, Integration & Modern Ops Practices - CICS Liberty environments are exposed to modern integration patterns and strict security requirements. Essential skills/knowledge/experience: • CICS system setup and configuration (regions, JVM servers) • Understanding of z/OS components used by CICS Liberty (USS, RACF, TCP/IP, SMF) • Capacity planning, performance tuning, and availability (HA/DR) • Problem determination using dumps, traces, SMF data, and logs • WebSphere Liberty configuration (server.xml, features, shared libraries) • JVM tuning for z/OS (heap sizing, GC behaviour) • Managing Java workload inside CICS (JVM servers lifecycle, diagnostics) • Patching and maintaining Liberty and Java SDK levels • RACF and TLS configuration (certificates, keyrings, SAF integration) • REST/HTTP exposure and API enablement • CI/CD awareness (bundles, pipelines, automated deployment) • Operational monitoring and log management