Re: Issue with: monit restart [service-name]

[Christopher Wood]

(inline)

On Tue, Jul 10, 2012 at 02:54:26PM -0400, Harlan Barnes wrote:
> Hello,
> 
> I am trying to setup monit (5.4) to watch my Wowza Media Server.
> 
> I can execute the following commands with no problem:
> 
> monit start wowza
> monit stop wowza
> 
> But when I try this:
> 
> monit restart wowza
> 
> it appears that wowza executes the stop script ... and then without
> waiting for it to return from the stop command, it executes the start
> command. This produces a race condition where the stop action removes
> the pid file that the start action just put down. As such, monit
> thinks the start action failed and does the start again. (Which causes
> other problems.)
> 
> Is that the way it is supposed to work? Is there anything I can do to
> force monit to wait for the stop action to return before executing the
> start action when I tell it to restart the service?
> 
> Thanks,
> 
> Harlan
> 
> ---
> My main config looks like this:
> 
> # set daemon mode timeout to 1 minute
> set daemon 60
> 
> # set the state file to
> set statefile /var/lib/monit/monit.state
> 
> # http support
> set httpd port 2812 and use the address localhost
>     allow localhost
> 
> # Include all files from /etc/monit.d/
> include /etc/monit.d/*
> 
> My wowza config looks like this:
> 
> check process wowza with pidfile /var/run/WowzaMediaServer.pid
>     start program = "/etc/init.d/WowzaMediaServer start"

I mostly use "restart" in the "start program", that way the init script has 
better control over things like the pidfile.

>     stop program = "/etc/init.d/WowzaMediaServer stop"
>     if failed port 443 then restart
>     if failed host localhost port 443 type TCPSSL
>         protocol HTTP request "/crossdomain.xml" then restart
> 
> Wowza says this on a verbose startup:
> 
> Runtime constants:
>  Control file       = /etc/monitrc
>  Log file           = /var/log/monit
>  Pid file           = /var/run/monit.pid
>  Id file            = /root/.monit.id
>  Debug              = True
>  Log                = True
>  Use syslog         = False
>  Is Daemon          = True
>  Use process engine = True
>  Poll time          = 60 seconds with start delay 0 seconds
>  Expect buffer      = 256 bytes
>  Mail from          = (not defined)
>  Mail subject       = (not defined)
>  Mail message       = (not defined)
>  Start monit httpd  = True
>  httpd bind address = localhost
>  httpd portnumber   = 2812
>  httpd signature    = True
>  Use ssl encryption = False
>  httpd auth. style  = Host/Net allow list
> 
> The service list contains the following entries:
> 
> Process Name          = wowza
>  Pid file             = /var/run/WowzaMediaServer.pid
>  Monitoring mode      = active
>  Start program        = '/etc/init.d/WowzaMediaServer start' timeout
> 30 second(s)
>  Stop program         = '/etc/init.d/WowzaMediaServer stop' timeout 30 
> second(s)
>  Existence            = if does not exist 1 times within 1 cycle(s)
> then restart else if succeeded 1 times within 1 cycle(s) then alert
>  Pid                  = if changed 1 times within 1 cycle(s) then alert
>  Ppid                 = if changed 1 times within 1 cycle(s) then alert
>  Port                 = if failed [localhost:443/crossdomain.xml [HTTP
> via TCPSSL] with timeout 5 seconds and retry 0 time(s)] 1 times within
> 1 cycle(s) then restart else if succeeded 1 times within 1 cycle(s)
> then alert
>  Port                 = if failed [localhost:443 [DEFAULT via TCP]
> with timeout 5 seconds and retry 0 time(s)] 1 times within 1 cycle(s)
> then restart else if succeeded 1 times within 1 cycle(s) then alert
> 
> System Name           = system_webcam_v5a
>  Monitoring mode      = active
> 
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