penbw − pen backend watcher: monitor & automatically blacklist backends of pen
penbw [−fnd] [-V|--version] [-h|--help] [−s sec] [−t sec] PENCTLHOST:PENCTLPORT
penbw is a small utility written in C for pen that monitors backend servers of pen in the background as daemon and if detect a backend as "failed" blacklist it through the provided pen control port similiar to "penctl host:port server 0 blacklist 300"
pen itself is able to detect if a backend is down and will blacklist on the fly. But if for ex. the backend is still accepting connections and simply sending back bogus or nothing, pen will not detect that, as pen doesn’t care about application-level protocols. This is where penbw comes in.
All you need is a from the host running penbw reachable control port (opt -C to pen) of pen. Even if the given control port is not available penbw will run/keep running and "wait" for the given control port to be available, so there is no need to restart penbw after pen has been restarted.
penbw connects directly to the control port, so it isn’t even neccessary to have pen(ctl) binarys on the host running penbw. Running pen on the host that is running pen is recommended.
If you would start pen like this:
# pen [options to pen] -C 127.0.0.1:1080
start penbw like that:
# penbw 127.0.0.1:1080
That’s it. Logging is going to syslog.
−u username
switch to unprivileged user if starting as privileged user username after startup and basic sanity checks
−s sec
Specifies the time in seconds to wait after each round of checks [60]
−t sec
Specifies the timeout for connects/reads/writes to backend servers and to pen [5]
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−f |
Stay in foreground |
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−n |
Don’t actually blacklist backends detected as "failed" - check and report only |
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−d |
Increase debug-level by 1 (repeat -d for more) |
−h | --help
print short help/usage and exit
−V | --version
print version and exit
Thomas A.F. Eckhardt <tafe unkelhaeusser net> - penbw is based on pen(ctl) by Ulric Eriksson <ulric siag nu>
pen(1), penctl(1)