Docker Version 1.12
,
I got a Dockerfile
from Here
FROM nginx:latest
RUN touch /marker
ADD ./check_running.sh /check_running.sh
RUN chmod +x /check_running.sh
HEALTHCHECK --interval=5s --timeout=3s CMD ./check_running.sh
I'm able to roll the updates and health checks with check_running.sh
shell script. Here, the check_running.sh
script is copied to image
, so the launched container has it.
Now, my question is there any way to Health Check from out side of the container and script also located outside.
I'm excepting a health check command to get the container performance(Depends on what we wrote in script), IF the container is not performing good it should roll-back to previous version ( Kind of a process that monitors the containers, if it is not good, it should roll-back to previous)
Thanks
is there any way to Health Check from out side of the container and script also located outside.
Kind of a process that monitors the containers, if it is not good, it should roll-back to previous
You have several options:
cat script.sh | docker exec -it container sh -s
.ps -Zax
or try looking for children of the daemon), or you can give each container a specific user ID with --user 12345
and then look for that or e.g. connecting to its services. You'd have to make sure it's running inside the right container. You can access the containers' filesystem below /var/lib/docker/devicemapper/mnt/<hash>/rootfs
.docker inspect --format='{{json .State.Health.Status}}' <containername>
combined with e.g. a line in the Dockerfile:
HEALTHCHECK CMD wget -q -s http://google.com
to check the container has internet access.I'd recommend option 3, because it's likely to be more compatible with other tools in the future.