update kube_node_status_{capacity/allocatable} doc to clarify difference

docs/node-metrics.md

@@ -8,7 +8,7 @@
 | kube_node_role | Gauge | The role of a cluster node | | `node`=&lt;node-address&gt; <br> `role`=&lt;NODE_ROLE&gt; | EXPERIMENTAL |
 | kube_node_spec_unschedulable | Gauge | Whether a node can schedule new pods | | `node`=&lt;node-address&gt;| STABLE |
 | kube_node_spec_taint | Gauge | The taint of a cluster node. | |`node`=&lt;node-address&gt; <br> `key`=&lt;taint-key&gt; <br> `value=`&lt;taint-value&gt; <br> `effect=`&lt;taint-effect&gt; | STABLE |
-| kube_node_status_capacity | Gauge | The capacity for different resources of a node | `cpu`=&lt;core&gt; <br> `ephemeral_storage`=&lt;byte&gt; <br> `pods`=&lt;integer&gt; <br> `attachable_volumes_*`=&lt;byte&gt; <br> `hugepages_*`=&lt;byte&gt; <br> `memory`=&lt;byte&gt; |`node`=&lt;node-address&gt; <br> `resource`=&lt;resource-name&gt; <br> `unit`=&lt;resource-unit&gt;| STABLE |
-| kube_node_status_allocatable | Gauge | The allocatable for different resources of a node that are available for scheduling | `cpu`=&lt;core&gt; <br> `ephemeral_storage`=&lt;byte&gt; <br> `pods`=&lt;integer&gt; <br> `attachable_volumes_*`=&lt;byte&gt; <br> `hugepages_*`=&lt;byte&gt; <br> `memory`=&lt;byte&gt; |`node`=&lt;node-address&gt; <br> `resource`=&lt;resource-name&gt; <br> `unit`=&lt;resource-unit&gt;| STABLE |
+| kube_node_status_capacity | Gauge | The total amount of resources available for a node | `cpu`=&lt;core&gt; <br> `ephemeral_storage`=&lt;byte&gt; <br> `pods`=&lt;integer&gt; <br> `attachable_volumes_*`=&lt;byte&gt; <br> `hugepages_*`=&lt;byte&gt; <br> `memory`=&lt;byte&gt; |`node`=&lt;node-address&gt; <br> `resource`=&lt;resource-name&gt; <br> `unit`=&lt;resource-unit&gt;| STABLE |
+| kube_node_status_allocatable | Gauge | The amount of resources allocatable for pods (after reserving some for system daemons) | `cpu`=&lt;core&gt; <br> `ephemeral_storage`=&lt;byte&gt; <br> `pods`=&lt;integer&gt; <br> `attachable_volumes_*`=&lt;byte&gt; <br> `hugepages_*`=&lt;byte&gt; <br> `memory`=&lt;byte&gt; |`node`=&lt;node-address&gt; <br> `resource`=&lt;resource-name&gt; <br> `unit`=&lt;resource-unit&gt;| STABLE |
 | kube_node_status_condition | Gauge | The condition of a cluster node | |`node`=&lt;node-address&gt; <br> `condition`=&lt;node-condition&gt; <br> `status`=&lt;true\|false\|unknown&gt; | STABLE |
 | kube_node_created | Gauge | Unix creation timestamp | seconds |`node`=&lt;node-address&gt;| STABLE |