Appealing Points:
- Opportunity to work ike deep-dive performance tuning (sysctl, tuna, /proc) to optimize RHEL for real-time (RT) workloads.
- Hands-on role using Kubernetes, Linux (RHEL 8/9, Rocky Linux), Docker, Helm, Git
- Collaborative bilingual environment that supports technical growth while strengthening leadership and cross-functional communication skills
Annual salary : 10 Million yen and Above.
Job Responsibilities:
- Kernel-Level Optimization: Conduct deep-dive performance tuning (sysctl, tuna, /proc) to optimize RHEL for real-time (RT) workloads.
- RAN Workload Tuning: Configure and tune vCU/vDU components, implementing CPU isolation (isolcpus), IRQ affinity, and NUMA alignment to achieve deterministic performance.
- Network Acceleration: Optimize packet processing using DPDK and SR-IOV to bypass kernel bottlenecks for high-throughput RAN traffic.
- Advanced Troubleshooting: Lead Root Cause Analysis (RCA) for high-severity incidents using advanced tracing tools (ftrace, trace-cmd, perf).
- Automation & Hardening: Develop complex Ansible playbooks to automate kernel hardening and performance profile deployments across large-scale clusters.
- Lifecycle Management: Manage vulnerability patching, OS upgrades, and hardware-software interaction (Intel RDT, CAT, BIOS-level tuning).
- Virtualization: Expert management of KVM/QEMU, Red Hat OpenShift Virtualization, and containerized vDU pods within Kubernetes.
Job Qualifications:
- experience: 8–12 years of relevant experience in telecommunications infrastructure engineering or SRE, with a proven track record in large-scale, complex environments.
- Kubernetes & Virtualization: Deep knowledge of bare-metal Kubernetes deployments and virtualization in development/production environments.
- Networking: Expertise in host-level networking, DNS/DHCP architecture, TLS management, load balancing, and advanced container networking.
- SRE Practices: Proven application of SRE principles, including major incident leadership, capacity/scalability strategy, and advanced change management.
- Security: Strong architectural knowledge of security hardening, RBAC models, pod security mechanisms, and secret management.
- Technical Depth: In-depth knowledge of process scheduling (SCHED_DEADLINE, SCHED_FIFO), memory management, and I/O schedulers.
Technical Skills & Tools
- Core: Kubernetes, Linux (RHEL 8/9, Rocky Linux), Docker, Helm, Git
- Hardware: Supermicro, Dell iDRAC, HP
- Automation: Ansible, Python, Shell
- Monitoring/Diagnostics: top, htop, vmstat, iostat, pqos, ftrace, perf
- Certifications: RHEL, CKA (Certified Kubernetes Administrator)
Language: Business level english, Japanese not mandaory
About Company
The largest eCommerce company in Japan, and the third-largest eCommerce marketplace company worldwide. The organization provides a variety of consumer and business-focused services including e-commerce, e-reading, travel, banking, securities, credit card, e-money, portal and media, online marketing, and professional sports. The company is expanding globally and currently has operations throughout Asia, Western Europe, and the Americas.
[Measures against passive smoking]
No smoking indoors allowed
Designated smoking area
. Skillset Required: Performance tuning, sysctl, tuna, /proc, RHEL, Real-time workloads, Kubernetes, Linux (RHEL 8, RHEL 9, Rocky Linux), Docker, Helm, Git, Cross-functional communication, Kernel-Level Optimization, CPU isolation, isolcpus, IRQ affinity