diff --git a/aconfig/aconfig_declarations.go b/aconfig/aconfig_declarations.go
index d29e312..71a64dd 100644
--- a/aconfig/aconfig_declarations.go
+++ b/aconfig/aconfig_declarations.go
@@ -73,8 +73,9 @@
 	if len(module.properties.Package) == 0 {
 		ctx.PropertyErrorf("package", "missing package property")
 	}
-	// TODO(b/311155208): Add mandatory check for container after all pre-existing
-	// ones are changed.
+	if len(module.properties.Container) == 0 {
+		ctx.PropertyErrorf("container", "missing container property")
+	}
 
 	// Add a dependency on the aconfig_value_sets defined in
 	// RELEASE_ACONFIG_VALUE_SETS, and add any aconfig_values that
diff --git a/aconfig/aconfig_declarations_test.go b/aconfig/aconfig_declarations_test.go
index 5201fed..c37274c 100644
--- a/aconfig/aconfig_declarations_test.go
+++ b/aconfig/aconfig_declarations_test.go
@@ -88,19 +88,49 @@
 	android.AssertStringEquals(t, "rule must contain container", rule.Args["container"], "--container com.android.foo")
 }
 
-func TestAconfigDeclarationsWithoutContainer(t *testing.T) {
-	bp := `
-		aconfig_declarations {
-			name: "module_name",
-			package: "com.example.package",
-			srcs: [
-				"foo.aconfig",
-			],
-		}
-	`
-	result := runTest(t, android.FixtureExpectsNoErrors, bp)
-
-	module := result.ModuleForTests("module_name", "")
-	rule := module.Rule("aconfig")
-	android.AssertIntEquals(t, "rule must not contain container", len(rule.Args["container"]), 0)
+func TestMandatoryProperties(t *testing.T) {
+	testCases := []struct {
+		name          string
+		expectedError string
+		bp            string
+	}{
+		{
+			name: "Srcs missing from aconfig_declarations",
+			bp: `
+				aconfig_declarations {
+					name: "my_aconfig_declarations_foo",
+					package: "com.example.package",
+					container: "otherapex",
+				}`,
+			expectedError: `missing source files`,
+		},
+		{
+			name: "Package missing from aconfig_declarations",
+			bp: `
+				aconfig_declarations {
+					name: "my_aconfig_declarations_foo",
+					container: "otherapex",
+					srcs: ["foo.aconfig"],
+				}`,
+			expectedError: `missing package property`,
+		},
+		{
+			name: "Container missing from aconfig_declarations",
+			bp: `
+				aconfig_declarations {
+					name: "my_aconfig_declarations_foo",
+					package: "com.example.package",
+					srcs: ["foo.aconfig"],
+				}`,
+			expectedError: `missing container property`,
+		},
+	}
+	for _, test := range testCases {
+		t.Run(test.name, func(t *testing.T) {
+			errorHandler := android.FixtureExpectsAtLeastOneErrorMatchingPattern(test.expectedError)
+			android.GroupFixturePreparers(PrepareForTestWithAconfigBuildComponents).
+				ExtendWithErrorHandler(errorHandler).
+				RunTestWithBp(t, test.bp)
+		})
+	}
 }
diff --git a/aconfig/codegen/aconfig_declarations_group_test.go b/aconfig/codegen/aconfig_declarations_group_test.go
index ec7cea3..c69d21f 100644
--- a/aconfig/codegen/aconfig_declarations_group_test.go
+++ b/aconfig/codegen/aconfig_declarations_group_test.go
@@ -15,9 +15,10 @@
 package codegen
 
 import (
+	"testing"
+
 	"android/soong/android"
 	"android/soong/java"
-	"testing"
 )
 
 func TestAconfigDeclarationsGroup(t *testing.T) {
@@ -28,6 +29,7 @@
 		aconfig_declarations {
 			name: "foo-aconfig",
 			package: "com.example.package",
+			container: "com.android.foo",
 			srcs: ["foo.aconfig"],
 		}
 
@@ -39,6 +41,7 @@
 		aconfig_declarations {
 			name: "bar-aconfig",
 			package: "com.example.package",
+			container: "com.android.foo",
 			srcs: ["foo.aconfig"],
 		}
 
diff --git a/aconfig/codegen/cc_aconfig_library_test.go b/aconfig/codegen/cc_aconfig_library_test.go
index 2e7fdc2..36f8b0e 100644
--- a/aconfig/codegen/cc_aconfig_library_test.go
+++ b/aconfig/codegen/cc_aconfig_library_test.go
@@ -50,6 +50,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 
@@ -112,6 +113,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 
@@ -167,6 +169,7 @@
 		aconfig_declarations {
 			name: "my_aconfig_declarations_bar",
 			package: "com.example.package",
+			container: "com.android.foo",
 			srcs: ["bar.aconfig"],
 		}
 
@@ -241,6 +244,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 
diff --git a/aconfig/codegen/java_aconfig_library_test.go b/aconfig/codegen/java_aconfig_library_test.go
index de45b5c..87b54a4 100644
--- a/aconfig/codegen/java_aconfig_library_test.go
+++ b/aconfig/codegen/java_aconfig_library_test.go
@@ -35,6 +35,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations_foo",
 				package: "com.example.package.foo",
+				container: "system",
 				srcs: ["foo.aconfig"],
 			}
 
@@ -46,6 +47,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations_bar",
 				package: "com.example.package.bar",
+				container: "system",
 				srcs: ["bar.aconfig"],
 			}
 
@@ -60,7 +62,7 @@
 	entry := android.AndroidMkEntriesForTest(t, result.TestContext, module)[0]
 
 	makeVar := entry.EntryMap["LOCAL_ACONFIG_FILES"]
-	android.EnsureListContainsSuffix(t, makeVar, "android_common/aconfig_merged.pb")
+	android.EnsureListContainsSuffix(t, makeVar, "android_common/system/aconfig_merged.pb")
 }
 
 func TestAndroidMkJavaLibrary(t *testing.T) {
@@ -175,6 +177,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 				exportable: true,
 			}
@@ -200,6 +203,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 
@@ -234,3 +238,52 @@
 func TestUnsupportedMode(t *testing.T) {
 	testCodegenModeWithError(t, "mode: `unsupported`,", "mode: \"unsupported\" is not a supported mode")
 }
+
+func TestMkEntriesMatchedContainer(t *testing.T) {
+	result := android.GroupFixturePreparers(
+		PrepareForTestWithAconfigBuildComponents,
+		java.PrepareForTestWithJavaDefaultModules).
+		ExtendWithErrorHandler(android.FixtureExpectsNoErrors).
+		RunTestWithBp(t, `
+			aconfig_declarations {
+				name: "my_aconfig_declarations_foo",
+				package: "com.example.package.foo",
+				container: "system",
+				srcs: ["foo.aconfig"],
+			}
+
+			java_aconfig_library {
+				name: "my_java_aconfig_library_foo",
+				aconfig_declarations: "my_aconfig_declarations_foo",
+			}
+
+			aconfig_declarations {
+				name: "my_aconfig_declarations_bar",
+				package: "com.example.package.bar",
+				container: "system_ext",
+				srcs: ["bar.aconfig"],
+			}
+
+			java_aconfig_library {
+				name: "my_java_aconfig_library_bar",
+				aconfig_declarations: "my_aconfig_declarations_bar",
+			}
+
+			java_library {
+				name: "my_module",
+				srcs: [
+					"src/foo.java",
+				],
+				static_libs: [
+					"my_java_aconfig_library_foo",
+					"my_java_aconfig_library_bar",
+				],
+				platform_apis: true,
+			}
+		`)
+
+	module := result.ModuleForTests("my_module", "android_common").Module()
+	entry := android.AndroidMkEntriesForTest(t, result.TestContext, module)[0]
+	makeVar := entry.EntryMap["LOCAL_ACONFIG_FILES"]
+	android.EnsureListContainsSuffix(t, makeVar, "my_aconfig_declarations_foo/intermediate.pb")
+}
diff --git a/aconfig/codegen/rust_aconfig_library_test.go b/aconfig/codegen/rust_aconfig_library_test.go
index fe28f94..523b464 100644
--- a/aconfig/codegen/rust_aconfig_library_test.go
+++ b/aconfig/codegen/rust_aconfig_library_test.go
@@ -46,6 +46,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 
@@ -131,6 +132,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 			rust_aconfig_library {
@@ -193,6 +195,7 @@
 			aconfig_declarations {
 				name: "my_aconfig_declarations",
 				package: "com.example.package",
+				container: "com.android.foo",
 				srcs: ["foo.aconfig"],
 			}
 			rust_aconfig_library {
diff --git a/apex/apex_test.go b/apex/apex_test.go
index 8a3735c..9254014 100644
--- a/apex/apex_test.go
+++ b/apex/apex_test.go
@@ -11425,6 +11425,7 @@
 			aconfig_declarations {
 				name: "%[1]s",
 				package: "com.example.package",
+				container: "system",
 				srcs: [
 					"%[1]s.aconfig",
 				],
diff --git a/java/aar_test.go b/java/aar_test.go
index d6dbe3c..18efd20 100644
--- a/java/aar_test.go
+++ b/java/aar_test.go
@@ -15,8 +15,9 @@
 package java
 
 import (
-	"android/soong/android"
 	"testing"
+
+	"android/soong/android"
 )
 
 func TestAarImportProducesJniPackages(t *testing.T) {
@@ -98,6 +99,7 @@
 		aconfig_declarations {
 			name: "bar",
 			package: "com.example.package.bar",
+			container: "com.android.foo",
 			srcs: [
 				"bar.aconfig",
 			],
@@ -105,6 +107,7 @@
 		aconfig_declarations {
 			name: "baz",
 			package: "com.example.package.baz",
+			container: "com.android.foo",
 			srcs: [
 				"baz.aconfig",
 			],
diff --git a/java/app_test.go b/java/app_test.go
index eab40e7..a7c48a1 100644
--- a/java/app_test.go
+++ b/java/app_test.go
@@ -4382,6 +4382,7 @@
 		aconfig_declarations {
 			name: "bar",
 			package: "com.example.package.bar",
+			container: "com.android.foo",
 			srcs: [
 				"bar.aconfig",
 			],
@@ -4389,6 +4390,7 @@
 		aconfig_declarations {
 			name: "baz",
 			package: "com.example.package.baz",
+			container: "com.android.foo",
 			srcs: [
 				"baz.aconfig",
 			],
diff --git a/java/droidstubs_test.go b/java/droidstubs_test.go
index 8da695f..6a14f36 100644
--- a/java/droidstubs_test.go
+++ b/java/droidstubs_test.go
@@ -379,6 +379,7 @@
 	aconfig_declarations {
 		name: "bar",
 		package: "com.example.package",
+		container: "com.android.foo",
 		srcs: [
 			"bar.aconfig",
 		],
@@ -434,6 +435,7 @@
 	aconfig_declarations {
 		name: "bar",
 		package: "com.example.package",
+		container: "com.android.foo",
 		srcs: [
 			"bar.aconfig",
 		],
diff --git a/java/java_test.go b/java/java_test.go
index a1192bb..2f27932 100644
--- a/java/java_test.go
+++ b/java/java_test.go
@@ -2801,6 +2801,7 @@
 	aconfig_declarations {
 		name: "bar",
 		package: "com.example.package",
+		container: "com.android.foo",
 		srcs: [
 			"bar.aconfig",
 		],
diff --git a/java/rro_test.go b/java/rro_test.go
index d697ec6..742c839 100644
--- a/java/rro_test.go
+++ b/java/rro_test.go
@@ -421,6 +421,7 @@
 		aconfig_declarations {
 			name: "bar",
 			package: "com.example.package.bar",
+			container: "com.android.foo",
 			srcs: [
 				"bar.aconfig",
 			],
@@ -428,6 +429,7 @@
 		aconfig_declarations {
 			name: "baz",
 			package: "com.example.package.baz",
+			container: "com.android.foo",
 			srcs: [
 				"baz.aconfig",
 			],
diff --git a/java/sdk_library_test.go b/java/sdk_library_test.go
index 0f163e6..34c63ac 100644
--- a/java/sdk_library_test.go
+++ b/java/sdk_library_test.go
@@ -1715,6 +1715,7 @@
 		aconfig_declarations {
 			name: "bar",
 			package: "com.example.package",
+			container: "com.android.foo",
 			srcs: [
 				"bar.aconfig",
 			],