Systems

Systems

1. Load balancing: workload -> resources

   • Network load balancing: client network tasks -> backends
     • Service discovery, Health checking, load balancing
   • Benefits: fault tolerance, performance, name abstraction
   • Features: configuration GUI, sticky sessions, DoS rate limiting, TLS
   • L4 LB: client <-> edge router -> L4 LB -> Backend
   • L7 LB: client <-> streams <-> LB <-> backends
     • Messaging protocol, logical + physical, TLS
     • Middle proxy: client <-> LB <-> backend
       • Edge proxy: client <-> internet <-> LB <-> backend
     • Embedded client library: Service, Client library <-> Backend
     • Sidecar: service <-> sidecar proxy -> backend
       • Global LB: GLB <-> Sidecar proxy <-> Service & Backend zone

2. Diagnosis

   • Memory? free < 5% free
     • Heap memory
     • cat /proc/<pid>/[map,status]
   • CPU? vmstat < 5% id
     • Kernel? time -> user + sys >> real
       • Interuppts? cat \proc\interrupts
       • Syscalls? strace <process>
     • Application
   • Useful: sar
   • I/O? top -> high wa %
     • Disk vmstat -> many blocks
     • Network (ifconfig -> near network device limit)