This adds a small C binary for fighting zombies. It is mounted under
`/dev/init` and is prepended to the args specified by the user. You
enable it via a daemon flag, `dockerd --init`, as it is disable by
default for backwards compat.
You can also override the daemon option or specify this on a per
container basis with `docker run --init=true|false`.
You can test this by running a process like this as the pid 1 in a
container and see the extra zombie that appears in the container as it
is running.
```c
int main(int argc, char ** argv) {
pid_t pid = fork();
if (pid == 0) {
pid = fork();
if (pid == 0) {
exit(0);
}
sleep(3);
exit(0);
}
printf("got pid %d and exited\n", pid);
sleep(20);
}
```
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
This reduces memory usage with a lot of docker proxy processes.
On Docker for Mac we are currently carrying a patch to replace
the binary as we modify it to forward ports to the Mac rather
than the Linux VM, this allows us to simply replace this binary
in our packaging with one that has a compatible interface. This
patch does not provide an easy way to substitute a binary as
the interface is complex and there are few use cases, but where
needed this can be done.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
This installs docker and dockerd to `$DOCKER_MAKE_INSTALL_PREFIX/bin`, which
defaults to `/usr/local/bin`
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
