Merge pull request #15 from rhatdan/master

Fix up README.md

Author: rhatdan

README.md

@@ -3,16 +3,63 @@
 OCI systemd hook enables running systemd in docker and [OCI](https://github.com/opencontainers/specs)
 compatible runtimes such as runc.
 
+oci-systemd-hook
 It reads state over stdin and mounts a tmpfs at /run, /tmp, links in a journal directory from the host and
 creates /etc/machine-id file for a container.
 
-Installation
----------------
+This project produces a C binary that can be used with runc and Docker (with minor code changes).
+If you clone this branch and build/install `oci-systemd-hook`, a binary will be placed in
+`/usr/libexec/oci/hooks.d` named `oci-systemd-hook`. You can change this location by
+editing `HOOKSDIR` in the Makefile.
+
+Running Docker or OCI runc containers with this executable, oci-systemd-hook is called just before a container is started and after it is provisioned.  If the CMD to run inside of the container is init or systemd, this hook will configure
+the container image to run a systemd environment.
+
+oci-systemd-hook will do the following
+
+* Mount a tmpfs on /run and /tmp
+-  If there is content in the container image's /run and /tmp that content will be compied onto the tmpfs.
+* Will create a /etc/machine-id based on the the containers UUID
+* Will mount the hosts /sys/fs/cgroups file systemd read-only into the container
+- /sys/fs/cgroup/systemd will be mounted read/write into the container.
+
+When the container stops, these file systems will be removed.
+
+systemd is expected to be able to run within the container without requiring
+the --privileged option.  However you will still need to specify a special --stop signal.
+
+If you created a container image based on a dockerfile like the following:
+```
+cat Dockerfile
+FROM 		RHEL7
+ENV container docker
+RUN dnf -y install httpd; dnf clean all; systemctl enable httpd; systemctl disable dnf* dnf-makecache.timer
+CMD [ "/sbin/init" ]
+```
+
+You should be able to execute the following command:
+
+```
+docker run -ti --stop-signal=RTMIN+3 httpd
+```
+
+If you run this hook along with oci-register-machine oci hook, you will be able
+to show the containers journal information on the host, using journalctl.
+
+```
+journalctl -M CONTAINER_UUID
+```
+
+
+To build, install, clean-up:
+
+First, **clone** this branch, then:
+
 ```
-git clone https://github.com/mrunalp/hooks
-cd hooks
+git clone https://github.com/projectatomic/oci-systemd-hook
+cd oci-systemd-hook
 autoreconf -i
-./configure --libexecdir=/usr/libexec/docker/hooks.d
+./configure --libexecdir=/usr/libexec/oci/hooks.d
 make
 make install
 ```