libswarm demotime - logging
17 Jul 2014If you don't know what libswarm is take a gander at Libswarm in a nutshell
Just a quick demo showing off what libswarm can do with logging.
I will be using code from this gist: https://gist.github.com/cpuguy83/b7c0f42e903bc13c46d6
Demo time!
# start a container that prints to stdout
docker -H tcp://10.0.0.2:2375 run -d --entrypoint /bin/sh debian:jessie -c \
'while true; do echo this is a log message; sleep 1; done'
# fire up swarmd
./swarmd 'logforwarder tcp://10.0.0.2:2375' stdoutlogger
Getting logs tcp://10.0.0.2:2375 [agitated_yonath]
2014-07-17 19:04:22.42915222 +0000 UTC tcp://10.0.0.2:2375 agitated_yonath INFO this is a log message
2014-07-17 19:04:23.43114032 +0000 UTC tcp://10.0.0.2:2375 agitated_yonath INFO this is a log message
So we told swarmd to fire up the logforwarder backend and connect to the docker daemon on tcp://10.0.0.2:2375, attach to each of the containers in the daemon, convert the stdout/stderr streams to log messages and forward them into the stdoutlogger (which is a backend made simply for demo purposes) which prints to the terminal's stdout.
# Now lets connect to multiple daemons with multiple containers
docker -H tcp://10.0.0.2:2375 run -d --entrypoint /bin/sh debian:jessie -c \
'while true; do echo this is a log message; sleep 1; done'
docker -H tcp://10.0.0.2:2375 run -d --entrypoint /bin/sh debian:jessie -c \
'while true; do echo this is a log message; sleep 1; done'
docker -H tcp://10.0.0.3:2375 run -d --entrypoint /bin/sh debian:jessie -c \
'while true; do echo this is also a log message; sleep 1; done'
./swarmd 'logforwarder tcp://10.0.0.2:2375 tcp://10.0.0.3:2375' stdoutlogger
Getting logs tcp://10.0.0.2:2375 [agitated_yonath romantic_wozniak]
Getting logs tcp://10.0.0.3:2375 [hopeful_babbage]
2014-07-17 19:40:22.93898444 +0000 UTC tcp://10.0.0.2:2375 agitated_yonath INFO this is a log message
2014-07-17 19:40:23.26841138 +0000 UTC tcp://10.0.0.3:2375 hopeful_babbage INFO this is also a log message
2014-07-17 19:40:23.63765218 +0000 UTC tcp://10.0.0.2:2375 romantic_wozniak INFO this too is a log message
2014-07-17 19:40:23.94244022 +0000 UTC tcp://10.0.0.2:2375 agitated_yonath INFO this is a log message
2014-07-17 19:40:24.27086067 +0000 UTC tcp://10.0.0.3:2375 hopeful_babbage INFO this is also a log message
2014-07-17 19:40:24.64303259 +0000 UTC tcp://10.0.0.2:2375 romantic_wozniak INFO this too is a log message
Here we have the logforwarder connecting to 2 docker backends, attaching to each of the containers and forwarding the stdout/stderr streams to the stdoutlogger.
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Instead of stdoutlogger, this could be swapped out for syslog, logstash, whatever... it just needs to implement the libswarm Log verb.
