Update info on default VG selection by LVMS

Update the description of the logic to match the changes for
OCPBUGS-10242 in openshift/microshift#1530

clean up syntax of command for using LVMS

Signed-off-by: Doug Hellmann <[email protected]>

Author: dhellmann

modules/microshift-lvms-system-requirements.adoc

@@ -11,7 +11,13 @@ Using LVMS in {product-title} requires the following system specifications.
 [id="lvms-volume-group-name_{context}"]
 == Volume Group Name
 
-The default integration of LVMS uses a volume group named `rhel`. You can change the default name of the volume group in the configuration file. For details, read the "Configuring the LVMS" section of this document.
+The default integration of LVMS selects the default volume group dynamically. If there are no volume groups on the {product-title} host, LVMS is disabled. 
+
+If there is only one volume group on the {product-title} host, that volume group is used. If there are multiple volume groups,  the group `microshift` is used. If the `microshift` group is not found, LVMS is disabled. 
+
+If you want to use a specific volume group, LVMS must be configured to select that volume group. You can change the default name of the volume group in the configuration file. For details, read the "Configuring the LVMS" section of this document.
+
+You can change the default name of the volume group in the configuration file. For details, read the "Configuring the LVMS" section of this document.
 
 Prior to launching, the `lvmd.yaml` configuration file must specify an existing volume group on the node with sufficient capacity for workload storage. If the volume group does not exist, the node controller fails to start and enters a `CrashLoopBackoff` state.
 
@@ -24,4 +30,4 @@ The LVMS provisions storage in increments of 1 gigabyte (GB). Storage requests a
 ----
 Warning  ProvisioningFailed    3s (x2 over 5s)  topolvm.cybozu.com_topolvm-controller-858c78d96c-xttzp_0fa83aef-2070-4ae2-bcb9-163f818dcd9f failed to provision volume with
 StorageClass "topolvm-provisioner": rpc error: code = ResourceExhausted desc = no enough space left on VG: free=(BYTES_INT), requested=(BYTES_INT)
-----
+----

modules/microshift-using-lvms.adoc

@@ -16,7 +16,7 @@ Use the following procedure to provision and mount a logical volume to a pod.
 +
 [source,terminal]
 ----
-$ cat <<'EOF' | oc apply -f -
+$ cat <<EOF | oc apply -f -
 kind: PersistentVolumeClaim
 apiVersion: v1
 metadata: