Hi, maintainers,
I would like to discuss the specifications of pidfile.
Please let me know your opinion when you have time.
I understand the specifications of pidfile as:
- in daemon mode
Pid of workers are written to pidfile for the number of nbproc
- in master-worker mode
Only one pid of master is written to pidfile
If multiple haproxy are started under these specifications, the behavior as:
- in daemon mode
Run /usr/sbin/haproxy -D -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid,
then /usr/sbin/haproxy -D -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid.
- The pidfile created by the former is overwritten by the latter.
- The contents of the pidfile are pids for the latter nbproc.
- The haproxy processes have been started for both the former and the
latter.
The results are as follows:
~]# grep nbproc /etc/haproxy/haproxy.cfg
nbproc 5
~]# /usr/sbin/haproxy -D -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# ps -ef | grep -w haproxy | grep -vw grep
haproxy 17954 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17955 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17956 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17957 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17958 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# cat /run/haproxy.pid
17954
17955
17956
17957
17958
~]# /usr/sbin/haproxy -D -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# ps -ef | grep -w haproxy | grep -vw grep
haproxy 17954 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17955 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17956 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17957 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17958 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17972 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17973 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17974 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17975 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17976 1 0 00:50 ? 00:00:00 /usr/sbin/haproxy -D -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# cat /run/haproxy.pid
17972
17973
17974
17975
17976
~]#
- in master-worker mode
Run /usr/sbin/haproxy -W -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid,
then /usr/sbin/haproxy -W -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid.
- The pidfile created by the former is overwritten by the latter.
- The content of the pidfile has only one pid of the latter's master
- The haproxy processes have been started for both the former and the
latter.
The results are as follows:
~]# grep nbproc /etc/haproxy/haproxy.cfg
nbproc 5
~]# /usr/sbin/haproxy -W -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# ps -ef | grep -w haproxy | grep -vw grep
root 17991 1 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17992 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17993 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17994 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17995 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17996 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# cat /run/haproxy.pid
17991
~]# /usr/sbin/haproxy -W -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# ps -ef | grep -w haproxy | grep -vw grep
root 17991 1 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17992 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17993 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17994 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17995 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 17996 17991 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
root 18002 1 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 18003 18002 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 18004 18002 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 18005 18002 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 18006 18002 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
haproxy 18007 18002 0 00:54 ? 00:00:00 /usr/sbin/haproxy -W -f
/etc/haproxy/haproxy.cfg -p /run/haproxy.pid
~]# cat /run/haproxy.pid
18002
~]#
What should the pidfile specification be?
- If we enable the former and latter haproxy, we should include both pids in
the pidfile.
- If we enable only the former or latter pid to the pidfile, we should disable
multiple startup of haproxy.
For example,
- if the former is running, the latter cannot start.
- when the latter is started, the former is forcibly stopped.
Please let me know your opinion.
Best regards,
MIZUTA Takeshi
