Patch 1: This adds the possibility to start a container in a frozen state via a --start-frozen parameter added to lxc-start.
I'm not sure the implementation is ideal. There's probably some reusable cgroup code somewhere, but as far as I could tell it is mostly meant for the monitor, so I don't know which parts I can use within the child process. This can be useful for when you want to get a fully prepared and mounted namespace without running the container itself while having the changes happening in hooks applied. In our case mount hooks, in order to provide ways to push/pull files to/from the container or mount it without things like multiple-mount-protection preventing you from firing up the container before it's unmounted again. We're still weighing some other ways we could go but I thought I'd get some input about this patch since it doesn't seem to be too specific to go upstream. I've considered a few alternatives to this but I'm not sure if there are any good ones. I've considered an lxc.cgroup.freezer.state config entry, but that happens too early and lxc-start won't exit until the container is unfrozen. Same problem with a start-hook, beside the fact that it must be present in the container. (In theory one could open a handle to an executable which waits for a signal and pass /proc/self/fd/$handle as hook, but --daemonize always closes them.) The semantics of the the start hook is another part to consider. (Ignore? Add a parameter? Run later? Split?) Patch 2: comment fixups For the new function I used 'set_' instead of 'want_' as prefix to make their purpose more obvious. Should I change it to 'want_' or maybe change the cleanup patch to also rename the other functions to 'set_*'? Wolfgang Bumiller (2): lxc-start: added --start-frozen cleanup: lxc_container::want_* comment descriptions doc/lxc-start.sgml.in | 12 ++++++++++++ src/lxc/arguments.h | 3 +++ src/lxc/conf.h | 1 + src/lxc/lxc_start.c | 7 +++++++ src/lxc/lxccontainer.c | 16 ++++++++++++++++ src/lxc/lxccontainer.h | 19 ++++++++++++++----- src/lxc/start.c | 17 +++++++++++++++++ 7 files changed, 70 insertions(+), 5 deletions(-) -- 2.1.4 _______________________________________________ lxc-devel mailing list lxc-devel@lists.linuxcontainers.org http://lists.linuxcontainers.org/listinfo/lxc-devel
