Symptoms

• httpdmng --reconfigure-domain command is running endlessly.
• ps -auxf shows a lot of sw-engine child processes.
• Following lines in strace log:
  

  futex(0x7fdd80782ea0, FUTEX_WAKE, 1) = 0
  futex(0x7fdd80782ecc, FUTEX_WAIT_BITSET|FUTEX_CLOCK_REALTIME, 45, {1482241127, 934488000}, ffffffff) = -1 ETIMEDOUT (Connection timed out)
  stat("/proc/378", {st_mode=S_IFDIR|0555, st_size=0, ...}) = 0
  open("/proc/378/stat", O_RDONLY) = 8
  read(8, "378 (sw-engine-fpm) S 877 877 87"..., 8191) = 292
  close(8) = 0

Cause

sw-engine child processes are stucked.

Resolution

1. Restart sw-engine service:
   

   # systemctl restart sw-engine

2. Relaunch httpdmng utility:
   

   # httpdmng --reconfigure-domain example.tld