Nodes fix swap memory part 2

Author: Michael Burke

modules/nodes-nodes-swap-memory.adoc

@@ -1,39 +1,44 @@
 // Module included in the following assemblies:
 //
-// * nodes/nodes/nodes-nodes-managing.:_mod-docs-content-type: PROCEDURE
+// * nodes/nodes/nodes-nodes-managing.adoc
 
 :_mod-docs-content-type: PROCEDURE
 [id="nodes-nodes-swap-memory_{context}"]
 
-= Enabling swap memory use on nodes
+= Allowing swap memory use on nodes
 
-:FeatureName: Enabling swap memory use on nodes
+You can allow workloads on the cluster nodes to use swap memory.
+
+:FeatureName: Swap memory support on nodes
 include::snippets/technology-preview.adoc[]
 
 [NOTE]
 ====
-Enabling swap memory is only available for container-native virtualization (CNV) users or use cases.
+Swap memory support is available only for container-native virtualization (CNV) users or use cases.
 ====
 
-[WARNING]
-====
-Enabling swap memory can negatively impact workload performance and out-of-resource handling. Do not enable swap memory on control plane nodes.
-====
+To allow swap memory usage on your nodes, create a `kubeletconfig` custom resource (CR) to set the `failSwapOn` parameter to `false`. 
 
-To enable swap memory, create a `kubeletconfig` custom resource (CR) to set the `swapbehavior` parameter. You can set limited or unlimited swap memory:
+Optionally, you can control swap memory usage by {product-title} workloads on those nodes by setting the `swapBehavior` parameter to one of the following values:
 
-* Limited: Use the `LimitedSwap` value to limit how much swap memory workloads can use. Any workloads on the node that are not managed by {product-title} can still use swap memory. The `LimitedSwap` behavior depends on whether the node is running with Linux control groups link:https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/index.html[version 1 (cgroups v1)] or link:https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v2.html[version 2 (cgroup v2)]:
-** cgroup v1: {product-title} workloads can use any combination of memory and swap, up to the pod's memory limit, if set.
-** cgroup v2: {product-title} workloads cannot use swap memory.
+* `NoSwap` prevents {product-title} worloads from using swap memory.  
+* `LimitedSwap` allows {product-title} workloads that fall under the Burstable QoS class to use swap memory.
 
-* Unlimited: Use the `UnlimitedSwap` value to allow workloads to use as much swap memory as they request, up to the system limit.
+Regardless of the `swapBehavior` setting, any workloads that are not managed by {product-title} on that node can still use swap memory if the `failSwapOn` parameter is `false`.
 
-Because the kubelet will not start in the presence of swap memory without this configuration, you must enable swap memory in {product-title} before enabling swap memory on the nodes. If there is no swap memory present on a node, enabling swap memory in {product-title} has no effect.
+Because the kubelet will not start in the presence of swap memory without this configuration, you must allow swap memory in {product-title} before enabling swap memory on the nodes. If there is no swap memory present on a node, enabling swap memory in {product-title} has no effect.
+
+[WARNING]
+====
+Using swap memory can negatively impact workload performance and out-of-resource handling. Do not enable swap memory on control plane nodes.
+====
 
 .Prerequisites
 
 * You have a running {product-title} cluster that uses version 4.10 or later.
 
+* Your cluster is configured to use cgroup v2. Swap memory is not supported on nodes in clusters that use cgroup v1.
+
 * You are logged in to the cluster as a user with administrative privileges.
 
 * You have enabled the `TechPreviewNoUpgrade` feature set on the cluster (see _Nodes -> Working with clusters -> Enabling features using feature gates_).
@@ -43,8 +48,6 @@ Because the kubelet will not start in the presence of swap memory without this c
 Enabling the `TechPreviewNoUpgrade` feature set cannot be undone and prevents minor version updates. These feature sets are not recommended on production clusters.
 ====
 
-* If cgroup v2 is enabled on a node, you must enable swap accounting on the node, by setting the `swapaccount=1` kernel argument.
-
 .Procedure
 
 . Apply a custom label to the machine config pool where you want to allow swap memory.
@@ -73,6 +76,9 @@ spec:
 #...
 ----
 <1> Set to `false` to enable swap memory use on the associated nodes. Set to `true` to disable swap memory use.
-<2> Specify the swap memory behavior. If unspecified, the default is `LimitedSwap`.
+<2> Optional: Specify the swap memory behavior for {product-title} pods.
++
+* `NoSwap`: {product-title} pods cannot use swap. This is the default.
+* `LimitedSwap`: {product-title} pods of Burstable QoS class only are permitted to employ swap.
 
-. Enable swap memory on the machines.
+. Enable swap memory on the nodes by setting the `swapaccount=1` kernel argument and configure swap memory as needed.