add container-init support

Add support for executing an init binary as PID 1 in a container to
forward signals and reap processes.  When the `--init` flag is set for
podman-create or podman-run, the init binary is bind-mounted to
`/dev/init` in the container and "/dev/init --" is prepended to the
container's command.

The default base path of the container-init binary is `/usr/libexec/podman`
while the default binary is catatonit [1].  This default can be changed
permanently via the `init_path` field in the `libpod.conf` configuration
file (which is recommended for packaging) or temporarily via the
`--init-path` flag of podman-create and podman-run.

[1] https://github.com/openSUSE/catatonit

Fixes: #1670
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>

1 files changed, 8 insertions, 0 deletions

diff --git a/docs/podman-create.1.md b/docs/podman-create.1.md
index 97d6e77b1..3a75a4b00 100644
--- a/docs/podman-create.1.md
+++ b/docs/podman-create.1.md
@@ -276,6 +276,14 @@ tmpfs: The volume is mounted onto the container as a tmpfs, which allows the use
 content that disappears when the container is stopped.
 ignore: All volumes are just ignored and no action is taken.
 
+**--init**
+
+Run an init inside the container that forwards signals and reaps processes.
+
+**--init-path**=""
+
+Path to the container-init binary.
+
 **-i**, **--interactive**=*true*|*false*
 
 Keep STDIN open even if not attached. The default is *false*.