add debugging ignition procedure

modules/troubleshooting-debugging-ignition.adoc

@@ -0,0 +1,25 @@
+// Module included in the following assemblies:
+//
+// * support/troubleshooting/troubleshooting-operating-system-issues.adoc
+
+:_content-type: PROCEDURE
+[id="debugging-ignition_{context}"]
+= Debugging Ignition failures
+
+If a machine cannot be provisioned, Ignition fails and {op-system} will boot into the emergency shell. Use the following procedure to get debugging information.
+
+.Procedure
+
+. Run the following command to show which service units failed:
++
+[source,terminal]
+----
+$ systemctl --failed
+----
+
+. Optional: Run the following command on an individual service unit to find out more information:
++
+[source,terminal]
+----
+$ journalctl -u <unit>.service
+----

support/troubleshooting/troubleshooting-operating-system-issues.adoc

@@ -57,3 +57,5 @@ endif::[]
 * kdump.conf(5) — a manual page for the `/etc/kdump.conf` configuration file containing the full documentation of available options
 * kexec(8) — a manual page for the `kexec` package
 * link:https://access.redhat.com/site/solutions/6038[Red Hat Knowledgebase article] regarding kexec and kdump
+
+include::modules/troubleshooting-debugging-ignition.adoc[leveloffset=+1]