Get to Know the HAProxy Process Manager

blog20200706-01.sh

$ sudo systemctl status haproxy

Main PID: 7528 (haproxy)
    Tasks: 3 (limit: 1152)
   CGroup: /system.slice/haproxy.service
           ├─7528 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid -S /run/haproxy-master.sock
           └─7529 /usr/sbin/haproxy -Ws -f /etc/haproxy/haproxy.cfg -p /run/haproxy.pid -S /run/haproxy-master.sock

blog20200706-02.cfg

program dataplaneapi
    command /usr/local/bin/dataplaneapi --host 0.0.0.0 --port 5555 --haproxy-bin /usr/sbin/haproxy --config-file /etc/haproxy/haproxy.cfg --reload-cmd "systemctl reload haproxy" --reload-delay 5 --userlist haproxy-dataplaneapi
    no option start-on-reload

blog20200706-03.cfg

program mirror 
    command spoa-mirror --runtime 0 --mirror-url http://test.local

blog20200706-04.txt

-S /run/haproxy-master.sock

blog20200706-05.sh

$ echo 'help' | sudo socat /run/haproxy-master.sock -

  help           : this message
  prompt         : toggle interactive mode with prompt
  quit           : disconnect
  show cli sockets : dump list of cli sockets
  show cli level   : display the level of the current CLI session
  operator       : lower the level of the current CLI session to operator
  user           : lower the level of the current CLI session to user
  @<relative pid> : send a command to the <relative pid> process
  @!<pid>        : send a command to the <pid> process
  @master        : send a command to the master process
  show proc      : show processes status
  reload         : reload haproxy

blog20200706-06.sh

$ echo 'show proc' | sudo socat /run/haproxy-master.sock -

#<PID>          <type>          <relative PID>  <reloads>       <uptime>        <version>      
9730            master          0               0               0d00h00m19s     2.1.4-1ppa1~bionic

# workers
9732            worker          1               0               0d00h00m19s     2.1.4-1ppa1~bionic

# programs
9731            dataplaneapi    -               0               0d00h00m19s     -    

blog20200706-07.sh

$ echo '@1 show info' | sudo socat /run/haproxy-master.sock -

Name: HAProxy
Version: 2.1.4-1ppa1~bionic
Release_date: 2020/04/12
Nbthread: 2
Nbproc: 1
Process_num: 1
Pid: 9732