Base docker healthcheck on STDOUT logs











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I've got a script that outputs logs to STDOUT. I want to monitor this, and if x seconds passes without log output, the healthcheck should fail and the container should restart.



I've got something that I feel should work (using strace), but it's not. I'll post the files below. Does anyone have any idea how to solve this?



Dockerfile:



FROM ruby:2.5.1
RUN apt-get update
RUN dpkg --configure -a
ENV TZ=Europe/London
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y keyboard-configuration
RUN apt-get install -y --fix-missing curl gnupg build-essential mosh iceweasel git libappindicator1 postgresql libpq-dev xvfb xorg dbus-x11
RUN apt-get install -y --fix-missing libxss1 nodejs xfonts-100dpi xfonts-75dpi sqlite libindicator7 unzip wget curl bzip2 libssl-dev libreadline-dev zlib1g-dev strace
RUN ln -sf /usr/bin/nodejs /usr/local/bin/node
RUN gem install bundler activerecord activesupport watir watir-scroll nokogiri pg pry forgery rspec headless rake vcr webmock rails logger
WORKDIR /home/
COPY . .
HEALTHCHECK --interval=25s --timeout=5s --retries=5 CMD strace -p $(pgrep -n ruby) 2>&1 | grep -m 1 write(
CMD ["ruby", "./test.rb"]


test.rb:



require 'logger'
$logger = Logger.new(STDOUT)
$logger.level = Logger::DEBUG
loop do
sleep 5
$logger.warn 'hi'
end


Logs are outputting as expected when running docker container log, but the health status is always starting, and shortly after starting it will consider it failed and restart. I intend to use Docker Swarm once this is working.










share|improve this question






















  • I'd guess that it's because your loop never finishes, so the script is always running, therefore always in a starting state.
    – Rots
    Nov 20 at 2:09










  • @Rots thanks for the comment! Ok. That would explain the starting part, but not the fact that it becomes unhealthy far too early (e.g. with the script above, rather than one that runs for a while and then stops outputting logs before sleeping for a long time, which will also become unhealthy early).
    – Joe
    Nov 20 at 2:45










  • No problem. try commenting out the $logger.warn line. Perhaps it's looking for something there and reporting unhealthy. Else you might need to return something like 0 to report success.
    – Rots
    Nov 20 at 3:46










  • @Rots unfortunately not, changing the log level to debug still results in it going unhealthy while still outputting logs. I'm less concerned about the 'health: starting' than I am about it becoming unhealthy while logs are still going out.
    – Joe
    Nov 20 at 10:43










  • good try. Try setting the exit status with exit 0 or exit 1.
    – Rots
    Nov 20 at 19:56















up vote
0
down vote

favorite












I've got a script that outputs logs to STDOUT. I want to monitor this, and if x seconds passes without log output, the healthcheck should fail and the container should restart.



I've got something that I feel should work (using strace), but it's not. I'll post the files below. Does anyone have any idea how to solve this?



Dockerfile:



FROM ruby:2.5.1
RUN apt-get update
RUN dpkg --configure -a
ENV TZ=Europe/London
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y keyboard-configuration
RUN apt-get install -y --fix-missing curl gnupg build-essential mosh iceweasel git libappindicator1 postgresql libpq-dev xvfb xorg dbus-x11
RUN apt-get install -y --fix-missing libxss1 nodejs xfonts-100dpi xfonts-75dpi sqlite libindicator7 unzip wget curl bzip2 libssl-dev libreadline-dev zlib1g-dev strace
RUN ln -sf /usr/bin/nodejs /usr/local/bin/node
RUN gem install bundler activerecord activesupport watir watir-scroll nokogiri pg pry forgery rspec headless rake vcr webmock rails logger
WORKDIR /home/
COPY . .
HEALTHCHECK --interval=25s --timeout=5s --retries=5 CMD strace -p $(pgrep -n ruby) 2>&1 | grep -m 1 write(
CMD ["ruby", "./test.rb"]


test.rb:



require 'logger'
$logger = Logger.new(STDOUT)
$logger.level = Logger::DEBUG
loop do
sleep 5
$logger.warn 'hi'
end


Logs are outputting as expected when running docker container log, but the health status is always starting, and shortly after starting it will consider it failed and restart. I intend to use Docker Swarm once this is working.










share|improve this question






















  • I'd guess that it's because your loop never finishes, so the script is always running, therefore always in a starting state.
    – Rots
    Nov 20 at 2:09










  • @Rots thanks for the comment! Ok. That would explain the starting part, but not the fact that it becomes unhealthy far too early (e.g. with the script above, rather than one that runs for a while and then stops outputting logs before sleeping for a long time, which will also become unhealthy early).
    – Joe
    Nov 20 at 2:45










  • No problem. try commenting out the $logger.warn line. Perhaps it's looking for something there and reporting unhealthy. Else you might need to return something like 0 to report success.
    – Rots
    Nov 20 at 3:46










  • @Rots unfortunately not, changing the log level to debug still results in it going unhealthy while still outputting logs. I'm less concerned about the 'health: starting' than I am about it becoming unhealthy while logs are still going out.
    – Joe
    Nov 20 at 10:43










  • good try. Try setting the exit status with exit 0 or exit 1.
    – Rots
    Nov 20 at 19:56













up vote
0
down vote

favorite









up vote
0
down vote

favorite











I've got a script that outputs logs to STDOUT. I want to monitor this, and if x seconds passes without log output, the healthcheck should fail and the container should restart.



I've got something that I feel should work (using strace), but it's not. I'll post the files below. Does anyone have any idea how to solve this?



Dockerfile:



FROM ruby:2.5.1
RUN apt-get update
RUN dpkg --configure -a
ENV TZ=Europe/London
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y keyboard-configuration
RUN apt-get install -y --fix-missing curl gnupg build-essential mosh iceweasel git libappindicator1 postgresql libpq-dev xvfb xorg dbus-x11
RUN apt-get install -y --fix-missing libxss1 nodejs xfonts-100dpi xfonts-75dpi sqlite libindicator7 unzip wget curl bzip2 libssl-dev libreadline-dev zlib1g-dev strace
RUN ln -sf /usr/bin/nodejs /usr/local/bin/node
RUN gem install bundler activerecord activesupport watir watir-scroll nokogiri pg pry forgery rspec headless rake vcr webmock rails logger
WORKDIR /home/
COPY . .
HEALTHCHECK --interval=25s --timeout=5s --retries=5 CMD strace -p $(pgrep -n ruby) 2>&1 | grep -m 1 write(
CMD ["ruby", "./test.rb"]


test.rb:



require 'logger'
$logger = Logger.new(STDOUT)
$logger.level = Logger::DEBUG
loop do
sleep 5
$logger.warn 'hi'
end


Logs are outputting as expected when running docker container log, but the health status is always starting, and shortly after starting it will consider it failed and restart. I intend to use Docker Swarm once this is working.










share|improve this question













I've got a script that outputs logs to STDOUT. I want to monitor this, and if x seconds passes without log output, the healthcheck should fail and the container should restart.



I've got something that I feel should work (using strace), but it's not. I'll post the files below. Does anyone have any idea how to solve this?



Dockerfile:



FROM ruby:2.5.1
RUN apt-get update
RUN dpkg --configure -a
ENV TZ=Europe/London
RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
RUN DEBIAN_FRONTEND=noninteractive apt-get install -y keyboard-configuration
RUN apt-get install -y --fix-missing curl gnupg build-essential mosh iceweasel git libappindicator1 postgresql libpq-dev xvfb xorg dbus-x11
RUN apt-get install -y --fix-missing libxss1 nodejs xfonts-100dpi xfonts-75dpi sqlite libindicator7 unzip wget curl bzip2 libssl-dev libreadline-dev zlib1g-dev strace
RUN ln -sf /usr/bin/nodejs /usr/local/bin/node
RUN gem install bundler activerecord activesupport watir watir-scroll nokogiri pg pry forgery rspec headless rake vcr webmock rails logger
WORKDIR /home/
COPY . .
HEALTHCHECK --interval=25s --timeout=5s --retries=5 CMD strace -p $(pgrep -n ruby) 2>&1 | grep -m 1 write(
CMD ["ruby", "./test.rb"]


test.rb:



require 'logger'
$logger = Logger.new(STDOUT)
$logger.level = Logger::DEBUG
loop do
sleep 5
$logger.warn 'hi'
end


Logs are outputting as expected when running docker container log, but the health status is always starting, and shortly after starting it will consider it failed and restart. I intend to use Docker Swarm once this is working.







ruby docker docker-swarm health-monitoring






share|improve this question













share|improve this question











share|improve this question




share|improve this question










asked Nov 20 at 1:43









Joe

114315




114315












  • I'd guess that it's because your loop never finishes, so the script is always running, therefore always in a starting state.
    – Rots
    Nov 20 at 2:09










  • @Rots thanks for the comment! Ok. That would explain the starting part, but not the fact that it becomes unhealthy far too early (e.g. with the script above, rather than one that runs for a while and then stops outputting logs before sleeping for a long time, which will also become unhealthy early).
    – Joe
    Nov 20 at 2:45










  • No problem. try commenting out the $logger.warn line. Perhaps it's looking for something there and reporting unhealthy. Else you might need to return something like 0 to report success.
    – Rots
    Nov 20 at 3:46










  • @Rots unfortunately not, changing the log level to debug still results in it going unhealthy while still outputting logs. I'm less concerned about the 'health: starting' than I am about it becoming unhealthy while logs are still going out.
    – Joe
    Nov 20 at 10:43










  • good try. Try setting the exit status with exit 0 or exit 1.
    – Rots
    Nov 20 at 19:56


















  • I'd guess that it's because your loop never finishes, so the script is always running, therefore always in a starting state.
    – Rots
    Nov 20 at 2:09










  • @Rots thanks for the comment! Ok. That would explain the starting part, but not the fact that it becomes unhealthy far too early (e.g. with the script above, rather than one that runs for a while and then stops outputting logs before sleeping for a long time, which will also become unhealthy early).
    – Joe
    Nov 20 at 2:45










  • No problem. try commenting out the $logger.warn line. Perhaps it's looking for something there and reporting unhealthy. Else you might need to return something like 0 to report success.
    – Rots
    Nov 20 at 3:46










  • @Rots unfortunately not, changing the log level to debug still results in it going unhealthy while still outputting logs. I'm less concerned about the 'health: starting' than I am about it becoming unhealthy while logs are still going out.
    – Joe
    Nov 20 at 10:43










  • good try. Try setting the exit status with exit 0 or exit 1.
    – Rots
    Nov 20 at 19:56
















I'd guess that it's because your loop never finishes, so the script is always running, therefore always in a starting state.
– Rots
Nov 20 at 2:09




I'd guess that it's because your loop never finishes, so the script is always running, therefore always in a starting state.
– Rots
Nov 20 at 2:09












@Rots thanks for the comment! Ok. That would explain the starting part, but not the fact that it becomes unhealthy far too early (e.g. with the script above, rather than one that runs for a while and then stops outputting logs before sleeping for a long time, which will also become unhealthy early).
– Joe
Nov 20 at 2:45




@Rots thanks for the comment! Ok. That would explain the starting part, but not the fact that it becomes unhealthy far too early (e.g. with the script above, rather than one that runs for a while and then stops outputting logs before sleeping for a long time, which will also become unhealthy early).
– Joe
Nov 20 at 2:45












No problem. try commenting out the $logger.warn line. Perhaps it's looking for something there and reporting unhealthy. Else you might need to return something like 0 to report success.
– Rots
Nov 20 at 3:46




No problem. try commenting out the $logger.warn line. Perhaps it's looking for something there and reporting unhealthy. Else you might need to return something like 0 to report success.
– Rots
Nov 20 at 3:46












@Rots unfortunately not, changing the log level to debug still results in it going unhealthy while still outputting logs. I'm less concerned about the 'health: starting' than I am about it becoming unhealthy while logs are still going out.
– Joe
Nov 20 at 10:43




@Rots unfortunately not, changing the log level to debug still results in it going unhealthy while still outputting logs. I'm less concerned about the 'health: starting' than I am about it becoming unhealthy while logs are still going out.
– Joe
Nov 20 at 10:43












good try. Try setting the exit status with exit 0 or exit 1.
– Rots
Nov 20 at 19:56




good try. Try setting the exit status with exit 0 or exit 1.
– Rots
Nov 20 at 19:56

















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