Haproxy process are spawn twice in V1.5.18


#1

While starting haproxy with command #systemctl restart/start haproxy in centos…haproxy-systemd-wrapper spawns haproxy twice. Why it is so? Does it for multiprocessor programming?


#2

The systemd-wrapper spawns the master process which then spawns an actual child process. So yes, when haproxy is running in “single” process mode, there are actually 3 processes.

Note that in 1.8 we got rid of the systemd-wrapper, and we only have master -> child process left.


#3

So what is use of another haproxy child process. Does this work same things, as another is doing.


#4

The child process does the actual forwarding of traffic, the master process just manages the processes.

When you are not using multiprocess mode (nbproc), there is just 1 child process.
If you have nbproc 4 for example, you have 4 child processes.