edits from testing

Author: Michael Burke

machine_configuration/machine-config-pin-preload-images-about.adoc

@@ -1,20 +1,18 @@
 :_mod-docs-content-type: ASSEMBLY
 [id="machine-config-pin-preload-images-about"]
-= About preloading and pinning images
+= About pinning and preloading images
 include::_attributes/common-attributes.adoc[]
 :context: machine-config-operator
 
 toc::[]
 
-Slow and unreliable connections to an image registry can interfere with operations that require pulling images, such as updating a cluster or deploying an application. This can be helpful in cluster with low bandwidth, unreliable internet connectivity, or in a disconnected environment. 
+Slow and unreliable connections to an image registry can interfere with operations that require pulling images, such as updating a cluster or deploying an application. This can include clusters that have low bandwidth, unreliable internet connectivity, or clusters in a disconnected environment. 
 
-For example, an cluster update might require pulling more than one hundred images. Failure to pull those images causes retries that can interfere with the upgrade process and might cause the update fail. One way to improve that is to _preload_ the required images by pulling them in advance, before they are actually needed. Then, ensuring that the images are available when needed by _pinning_ them to a machine config pool. Pinning and preloading images can provide a more consistent upgrade, which is important when scheduling upgrades into maintenance windows.
+For example, a cluster update might require pulling more than one hundred images. Failure to pull those images could cause retries that can interfere with the upgrade process and might cause the update to fail. One way to improve that is to _preload_ the required images by pulling them in advance, before they are actually needed. Then, ensuring that the images are available when needed by _pinning_ them to a machine config pool. Pinning and preloading images can provide a more consistent upgrade, which is important when scheduling upgrades into maintenance windows.
 
-Pinning and preloading images can benefit a cluster that has a low bandwidth or an unreliable connection to an image registry server when deploying applications, ensuring that the images are available and application will successfully deploy in a predictable time.
+Pinning and preloading images ensures that the images are available and application can successfully deploy in a predictable time. Another benefit to pinning and preloading images is that image garbage collection does not remove the pinned images.
 
-Preloading and pinning images prevents image garbage collection from removing the pinned images.
-
-You can preload and pin images by using a a `PinnedImageSet` custom resource (CR) as described in the following section. Pinned images are stored in the file inside the `/etc/crio/crio.conf.d/50-pinned-iamges` directory. The contents of the file appear similar to the following example:
+You can pin and preload images by using a a `PinnedImageSet` custom resource (CR) as described in the following section. Pinned images are stored on the nodes in the `/etc/crio/crio.conf.d/50-pinned-iamges` file. The contents of the file appear similar to the following example:
 
 [source,terminal]
 ----
@@ -23,7 +21,7 @@ You can preload and pin images by using a a `PinnedImageSet` custom resource (CR
     pinned_images = ["quay.io/openshift-release-dev/ocp-release@sha256:4198606580b69c8335ad7ae531c3a74e51aee25db5faaf368234e8c8dae5cbea", "quay.io/openshift-release-dev/ocp-release@sha256:513cf1028aa1a021fa73d0601427a0fbcf6d212b88aaf9d76d4e4841a061e44e", "quay.io/openshift-release-dev/ocp-release@sha256:61eae2d261e54d1b8a0e05f6b5326228b00468364563745eed88460af04f909b"]
 ----
 
-Before pulling the images, the Machine Config Operator (MCO) verifies that there is enough space available on each affected node to store the images. If the node has sufficient space, the MCO creates the pinned image file, pulls the images, and reloads CRI-O.
+Before pulling the images, the Machine Config Operator (MCO) verifies that there is enough space available on each affected node to store the images. If the node has sufficient space, the MCO creates the pinned image file, pulls the images, and reloads CRI-O. If there is not sufficient space, the MCO does not pull the images and presents an error message. 
 
 include::modules/machine-config-pin-preload-images.adoc[leveloffset=+1]
 

modules/machine-config-pin-preload-images.adoc

@@ -4,11 +4,11 @@
 
 :_mod-docs-content-type: PROCEDURE
 [id="machine-config-pin-preload-images_{context}"]
-= Preloading and pinning and images
+= Pinning and preloading images
 
-You can preload and pin images by using a `PinnedImageSet` custom resource (CR). The pinned image set defines the list of images to preload and the machine config pool that the images should be pinned to. 
+You can pin and preload images by using a `PinnedImageSet` custom resource (CR). The pinned image set defines the list of images to preload and the machine config pool that the images should be pinned to. 
 
-The file is stored in the the `/etc/crio/crio.conf.d` directory under a name that is a concatenation of the name of the `PinnedImageSet` object and the UUID assigned to the object. 
+The images are stored in the the `/etc/crio/crio.conf.d/50-pinned-images` file on the nodes. 
 
 .Procedure
 
@@ -19,8 +19,8 @@ The file is stored in the the `/etc/crio/crio.conf.d` directory under a name tha
 apiVersion: machineconfiguration.openshift.io/v1
 kind: PinnedImageSet
 metadata:
-  labels:
-    machineconfiguration.openshift.io/role: worker <1>
+  labels: <1>
+    machineconfiguration.openshift.io/role: worker
   name: worker-pinned-images
 spec:
   pinnedImages: <2>
@@ -31,7 +31,7 @@ spec:
 where:
 +
 --
-`labels`:: Specifies an optional node selector to specify the machine config pool to pin the images to. If not specified, the images are pinned to all nodes in the cluster. the relative path to the downloaded ISO file, for example, `rhcos-live.iso`.
+`labels`:: Specifies an optional node selector to specify the machine config pool to pin the images to. If not specified, the images are pinned to all nodes in the cluster.
 `pinnedImages`:: Specifies a list of one or more images to preload.
 --
 
@@ -57,7 +57,7 @@ $ oc describe machineconfignode <machine_confignode_name>
 $ oc describe machineconfignode ci-ln-25hlkvt-72292-jrs48-worker-a-2bdj
 ----
 +
-.Example output
+.Example output for a successful image pull and pin
 +
 [source,terminal]
 ----
@@ -75,9 +75,9 @@ status
     name: worker-pinned-images
 ----
 +
-Any failures or error messages would appear in the `MachineConfigNode` object status fields.
+Any failures or error messages would appear in the `MachineConfigNode` object status fields, as shown in the following example:
 +
-.Example output
+.Example output for a failed image pull and pin
 +
 [source,terminal]
 ----
@@ -126,12 +126,6 @@ sh-5.1# chroot /host
 +
 [source,terminal]
 ----
-$ cat /etc/crio/crio.conf.d/<pinned_image_set_name>
-----
-+
-.Example command
-[source,terminal]
-----
 $ cat /etc/crio/crio.conf.d/50-pinned-images
 ----
 +