Docker build freezes installing packages from apt
apt-get, build, docker
Solution
You can check which process is running using e.g. `ps faux | less`. Scroll down to find the `lxc-start` process corresponding to your container, and see what is running under it (the `f` flag triggers a forest display which should show in a pretty obvious way which processes belong to the container).
Then, you can use `strace -fp <pid>` to attach to the last running process in that container and see what it is doing.
Last but not least, you can try to break down the command in 2 or 3 phases. In the (unlikely) case where the problem would come from a package prompting you for input (which shouldn't happen since you specified the `noninteractive` front-end, but who knows) that will help to single it out.
Problem
I have a dockerfile which needs installing some 720mb worth of packages from apt. ``` run DEBIAN_FRONTEND=noninteractive apt-get install -y python-pip python-dev\ supervisor mercurial subversion buildbot buildbot-slave subversion doxygen\ cmake cloc build-essential valgrind cccc scons g++ cppcheck qt4-dev-tools\ wget lcov graphviz ``` The build runs up to almost half of the packages requested, then it just hangs idle there. Is there a way to know for sure if the process has halted or if it's just idle waiting for the network or something along those lines?