replace netcat with socat for liveness probe/metrics #22
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We've had an issue on Google Kubernetes Engine, on a node with kernel version 4.14.138+, where liveness probes would regularly fail some percentage of the time. We've traced the problem down to the `poll()` system call sometimes failing in the `nc` command used in the liveness probe, whereupon `nc` returns an empty response, despite the TCP connection from Zookeeper clearly sending back an `imok`. Netcat uses `select()`, `poll()`, `read()`, where `poll()` sometimes throws an error because Zookeeper has closed the TCP connection. Socat uses `select()`, `read()`, which works here.
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yes,thank you |
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We've had an issue on Google Kubernetes Engine, on a node with
kernel version 4.14.138+, where liveness probes would regularly fail
some percentage of the time.
We've traced the problem down to the
poll()system call sometimesfailing in the
nccommand used in the liveness probe, whereuponncreturns an empty response, despite the TCP connection fromZookeeper clearly sending back an
imok.Netcat uses
select(),poll(),read(), wherepoll()sometimesthrows an error because Zookeeper has closed the TCP connection.
Socat uses
select(),read(), which works here.