Update docs and Containerfile to match

Fully tested README.md instructions end-to-end on F36.

Signed-off-by: Chris Evich <cevich@redhat.com>

README.md

@@ -27,21 +27,28 @@ lacks this feature, Several labels are set on the image to support
 easy registration and execution of a runner container using a special
 bash command.  See the examples below for more information.
 
-#### Volume Ownership Bug
+#### [Volume Ownership Bug](https://github.com/containers/podman/issues/16576)
 
-Some versions of podman contain a bug where named volumes aren't owned
-by the namespaced user within a rootless container (i.e. in conjunction
-with the --user option).  Since the `podman` user/group inside the `pipglr`
-container is known, it's possible to manually set/reset ownership:
+Some versions of podman contain a bug where named local volumes aren't owned
+by the namespaced user within a rootless container (i.e. the 'podman' user).
+Since the `podman` user/group inside the `pipglr` container is known, it's
+possible to manually setup ownership ahead of time. This should be be done
+once, prior to registering your runners:
 
 ```bash
-VOLUME=pipglr-podman-root
-podman volume create $VOLUME
-cd $(podman unshare podman volume mount $VOLUME)
-podman unshare chown 1000:1000
-podman volume unmount $VOLUME
+$ for VOLUME in pipglr-podman-root pipglr-config pipglr-podman-cache; do \
+    PUPVM="podman unshare podman volume mount $VOLUME"
+    podman volume create $VOLUME && \
+    podman unshare chown 1000:1000 $($PUPVM) && \
+    podman unshare chmod 02770 $($PUPVM) && \
+    podman unshare ls -land $($PUPVM) ; \
+  done
 ```
 
+If you get `podman system service` startup permission-denied errors, or
+errors from gitlab-runner, unable to connect to the podman socket, this is
+likely the cause.  You can fix it after-the-fact using the same commands as above, just add a `-R` option to the `chown`/`chmod`, and additionally target `./*`.
+
 #### Runner registration
 
 Each time the registration command is run, a new runner is added into
@@ -52,20 +59,27 @@ For modern versions of podman, registration can be performed with the
 following commands:
 
 ```bash
-IMAGE="=registry.gitlab.com/qontainers/pipglr:latest"
-echo '<actual registration token>' | podman secret create REGISTRATION_TOKEN -
-podman container runlabel $IMAGE register --secret REGISTRATION_TOKEN,type=env
+$ IMAGE="registry.gitlab.com/qontainers/pipglr:latest"
+$ echo '<actual registration token>' | podman secret create REGISTRATION_TOKEN -
+$ podman container runlabel register $IMAGE
 ```
 
 Where `<actual registration token>` is the value obtained from the "runners"
-settings page of a gitlab group or project.
+settings page of a gitlab group or project.  When you're finished registering
+as many runners as you want, the secret is no-longer needed and may be removed:
 
-Note: Some versions of podman don't support the `container runlabel` sub-command.
+```bash
+$ podman secret rm REGISTRATION_TOKEN
+```
+
+##### Note
+
+Some versions of podman don't support the `container runlabel` sub-command.
 If this is the case, you may simulate it with the following command (in addition
 to the other example commands above):
 
 ```bash
-eval $(podman inspect --format=json $IMAGE | jq -r .[].Labels.register)
+$ eval $(podman inspect --format=json $IMAGE | jq -r .[].Labels.register)
 ```
 
 #### Runner Startup
@@ -74,9 +88,11 @@ With one or more runners successfully registered and configured, the GitLab
 runner container may be launched with the following commands:
 
 ```bash
-podman container runlabel $IMAGE run
+$ podman container runlabel run $IMAGE
 ```
 
+##### Note
+
 As above, if you're missing the `container runlabel` sub-command, the following
 may be used instead (assuming `$IMAGE` remains set):
 
@@ -84,8 +100,24 @@ may be used instead (assuming `$IMAGE` remains set):
 $ eval $(podman inspect --format=json $IMAGE | jq -r .[].Labels.run)
 ```
 
+#### Runner configuration
+
+You may inspect/modify the gitlab-runner configuration as you see fit, just be
+sure to use the `podman unshare` command-wrapper to enter the usernamespace.
+For example, to display the config:
+
+```bash
+$ podman unshare $(podman unshare podman volume mount pipglr-config)/config.toml
+```
+
 #### Debugging
 
+The first thing to check is the container output:
+
+```bash
+$ podman logs --since 0 pipglr
+```
+
 Before starting the runner, you may `export PODMAN_RUNNER_DEBUG=debug` to enable
 debugging on the inner-podman.  Whereas `export LOG_LEVEL=debug` can be used to
 debug the gitlab-runner itself.
@@ -94,7 +126,9 @@ debug the gitlab-runner itself.
 
 This image may be built simply with:
 
-`podman build -t registry.gitlab.com/qontainers/pipglr:latest .`
+```bash
+$ podman build -t registry.gitlab.com/qontainers/pipglr:latest .
+```
 
 This will utilize the latest stable version of podman and the latest
 stable version of the gitlab runner.
@@ -140,10 +174,9 @@ Several build arguments are available to control the output image:
   and port supports various observability and debugging features of the
   gitlab runner.  For more information see the [gitlab runner advanced
   configuration documentation](https://docs.gitlab.com/runner/configuration/advanced-configuration.html#the-global-section).
-* `PRIVILEGED_RUNNER` - Defaults to 'false', may be set 'true'.  When
-  `true`, this causes inner-containers to be created with the `--privileged`
-  flag.  This is a potential security weakness, but is necessary for
-  (among other things) allowing nested container image builds.
+* `PRIVILEGED_RUNNER` - Defaults to 'true', may be set 'true' if you're brave.
+  However this may result in the gitlab-runner failing to launch inner-containers.
+  Setting it false will also prevent building container images using the runner.
 * `RUNNER_TAGS` - Defaults to `podman_in_podman`, may be set to any comma-separated
   list (with no spaces!) of tags.  These show up in GitLab (not the runner
   configuration), and determines where jobs are run.