Dockerfile and docs to run containerized playbooks

Update openshift-ansible's Dockerfile to use playbook2image as a base, with the
goal to run an arbitrary playbook from a container.

The existing Dockerfile is moved to Dockerfile.rhel7 for the productized version
and will be updated to use playbook2image later.

1 files changed, 41 insertions, 0 deletions

diff --git a/README_CONTAINER_IMAGE.md b/README_CONTAINER_IMAGE.md
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+# Containerized openshift-ansible to run playbooks
+
+The [Dockerfile](Dockerfile) in this repository uses the [playbook2image](https://github.com/aweiteka/playbook2image) source-to-image base image to containerize `openshift-ansible`. The resulting image can run any of the provided playbooks.
+
+**Note**: at this time there are known issues that prevent to run this image for installation/upgrade purposes from within one of the hosts that is also an installation target at the same time: if the playbook you want to run attempts to manage the docker daemon and restart it (like install/upgrade playbooks do) this would kill the container itself during its operation.
+
+## Build
+
+To build a container image of `openshift-ansible`:
+
+1. Using standalone **Docker**:
+
+        cd openshift-ansible
+        docker build -t openshift-ansible .
+
+1. Using an **OpenShift** build:
+
+        oc new-build docker.io/aweiteka/playbook2image~https://github.com/openshift/openshift-ansible
+        oc describe imagestream openshift-ansible
+
+## Usage
+
+The base image provides several options to control the behaviour of the containers. For more details on these options see the [playbook2image](https://github.com/aweiteka/playbook2image) documentation.
+
+At the very least, when running a container using an image built this way you must specify:
+
+1. The **playbook** to run. This is set using the `PLAYBOOK_FILE` environment variable.
+1. An **inventory** file. This can be mounted inside the container as a volume and specified with the `INVENTORY_FILE` environment variable. Alternatively you can serve the inventory file from a web server and use the `INVENTORY_URL` environment variable to fetch it.
+1. **ssh keys** so that Ansible can reach your hosts. These should be mounted as a volume under `/opt/app-root/src/.ssh`
+
+Here is an example of how to run a containerized `openshift-ansible` playbook that will check the expiration dates of OpenShift's internal certificates using the [`openshift_certificate_expiry` role](../../roles/openshift_certificate_expiry). The inventory and ssh keys are mounted as volumes (the latter requires setting the uid in the container and SELinux label in the key file via `:Z` so they can be accessed) and the `PLAYBOOK_FILE` environment variable is set to point to an example certificate check playbook that is already part of the image:
+
+    docker run -u `id -u` \
+           -v $HOME/.ssh/id_rsa:/opt/app-root/src/.ssh/id_rsa:Z \
+           -v /etc/ansible/hosts:/tmp/inventory \
+           -e INVENTORY_FILE=/tmp/inventory \
+           -e OPTS="-v" \
+           -e PLAYBOOK_FILE=playbooks/certificate_expiry/default.yaml \
+           openshift-ansible
+
+The [playbook2image examples](https://github.com/aweiteka/playbook2image/tree/master/examples) provide additional information on how to use a built image.