From 0951fe1c5011767da2ebe9839e4548e6e0690f36 Mon Sep 17 00:00:00 2001
From: hc-github-team-nomad-core
 <82989552+hc-github-team-nomad-core@users.noreply.github.com>
Date: Tue, 11 Jul 2023 10:00:05 -0500
Subject: [PATCH] backport of commit 0a5e90120b18ff450457463d6bcee68ec6804bb0
 (#17900)

This pull request was automerged via backport-assistant
---
 command/namespace_apply_test.go                | 18 ++++++++++++++++++
 nomad/structs/structs.go                       |  8 ++++----
 .../docs/other-specifications/namespace.mdx    | 12 ++++++------
 3 files changed, 28 insertions(+), 10 deletions(-)

diff --git a/command/namespace_apply_test.go b/command/namespace_apply_test.go
index 05154146c..08c840e48 100644
--- a/command/namespace_apply_test.go
+++ b/command/namespace_apply_test.go
@@ -120,6 +120,24 @@ meta {
 			input:    "",
 			expected: &api.Namespace{},
 		},
+		{
+			name: "lists in node pool config are nil if not provided",
+			input: `
+name = "nil-lists"
+
+node_pool_config {
+  default = "default"
+}
+`,
+			expected: &api.Namespace{
+				Name: "nil-lists",
+				NodePoolConfiguration: &api.NamespaceNodePoolConfiguration{
+					Default: "default",
+					Allowed: nil,
+					Denied:  nil,
+				},
+			},
+		},
 	}
 
 	for _, tc := range testCases {
diff --git a/nomad/structs/structs.go b/nomad/structs/structs.go
index 0b560c08e..ae8742949 100644
--- a/nomad/structs/structs.go
+++ b/nomad/structs/structs.go
@@ -5396,10 +5396,10 @@ type NamespaceNodePoolConfiguration struct {
 	Default string
 
 	// Allowed specifies the node pools that are allowed to be used by jobs in
-	// this namespace. This field supports wildcard globbing through the use
-	// of `*` for multi-character matching. If specified, only the node pools
-	// that match these patterns are allowed. This field cannot be used
-	// with Denied.
+	// this namespace. By default, all node pools are allowed. If an empty list
+	// is provided only the namespace's default node pool is allowed. This field
+	// supports wildcard globbing through the use of `*` for multi-character
+	// matching. This field cannot be used with Denied.
 	Allowed []string
 
 	// Denied specifies the node pools that are not allowed to be used by jobs
diff --git a/website/content/docs/other-specifications/namespace.mdx b/website/content/docs/other-specifications/namespace.mdx
index 56a61b0da..08e08f326 100644
--- a/website/content/docs/other-specifications/namespace.mdx
+++ b/website/content/docs/other-specifications/namespace.mdx
@@ -79,13 +79,13 @@ node_pool_config {
 - `default` `(string: "default")` - Specifies the node pool to use for jobs in
   this namespace that don't define a node pool in their specification.
 
-- `allowed` `(array<string>: [])` - Specifies the node pools that are allowed
-  to be used by jobs in this namespace. This field supports wildcard globbing
-  through the use of `*` for multi-character matching. If specified, only the
-  node pools that match these patterns are allowed. This field cannot be used
-  with `denied`.
+- `allowed` `(array<string>: nil)` - Specifies the node pools that are allowed
+  to be used by jobs in this namespace. By default, all node pools are allowed.
+  If an empty list is provided only the namespace's default node pool is
+  allowed. This field supports wildcard globbing through the use of `*` for
+  multi-character matching. This field cannot be used with `denied`.
 
-- `denied` `(array<string>: [])` - Specifies the node pools that are not
+- `denied` `(array<string>: nil)` - Specifies the node pools that are not
   allowed to be used by jobs in this namespace. This field supports wildcard
   globbing through the use of `*` for multi-character matching. If specified,
   any node pool is allowed to be used, except for those that match any of these