diff --git a/packages/@aws-cdk/aws-route53/lib/hosted-zone.ts b/packages/@aws-cdk/aws-route53/lib/hosted-zone.ts
index c7cd541703c57..c965021665b52 100644
--- a/packages/@aws-cdk/aws-route53/lib/hosted-zone.ts
+++ b/packages/@aws-cdk/aws-route53/lib/hosted-zone.ts
@@ -112,6 +112,10 @@ export class HostedZone extends Resource implements IHostedZone {
    * @see https://docs.aws.amazon.com/cdk/latest/guide/environments.html
    */
   public static fromLookup(scope: Construct, id: string, query: HostedZoneProviderProps): IHostedZone {
+    if (!query.domainName) {
+      throw new Error('Cannot use undefined value for attribute `domainName`');
+    }
+
     const DEFAULT_HOSTED_ZONE: HostedZoneContextResponse = {
       Id: 'DUMMY',
       Name: query.domainName,
diff --git a/packages/@aws-cdk/aws-route53/test/hosted-zone.test.ts b/packages/@aws-cdk/aws-route53/test/hosted-zone.test.ts
index f34d777220418..b659e41446d75 100644
--- a/packages/@aws-cdk/aws-route53/test/hosted-zone.test.ts
+++ b/packages/@aws-cdk/aws-route53/test/hosted-zone.test.ts
@@ -176,4 +176,19 @@ describe('hosted zone', () => {
       hz.zoneName;
     }).toThrow('Cannot reference `zoneName` when using `HostedZone.fromHostedZoneId()`. A construct consuming this hosted zone may be trying to reference its `zoneName`. If this is the case, use `fromHostedZoneAttributes()` or `fromLookup()` instead.');
   });
+
+  test('fromLookup throws error when domainName is undefined', () => {
+    // GIVEN
+    let domainName!: string;
+    const stack = new cdk.Stack(undefined, 'TestStack', {
+      env: { account: '123456789012', region: 'us-east-1' },
+    });
+
+    // THEN
+    expect(() => {
+      HostedZone.fromLookup(stack, 'HostedZone', {
+        domainName,
+      });
+    }).toThrow(/Cannot use undefined value for attribute `domainName`/);
+  });
 });
diff --git a/packages/@aws-cdk/lambda-layer-awscli/layer/requirements.txt b/packages/@aws-cdk/lambda-layer-awscli/layer/requirements.txt
index faa0808b05129..1aed1c536cca2 100644
--- a/packages/@aws-cdk/lambda-layer-awscli/layer/requirements.txt
+++ b/packages/@aws-cdk/lambda-layer-awscli/layer/requirements.txt
@@ -1 +1 @@
-awscli==1.25.46
+awscli==1.25.51
diff --git a/packages/@aws-cdk/pipelines/lib/main/pipeline-base.ts b/packages/@aws-cdk/pipelines/lib/main/pipeline-base.ts
index 34402b0b5cffa..0bb27cb78a7bc 100644
--- a/packages/@aws-cdk/pipelines/lib/main/pipeline-base.ts
+++ b/packages/@aws-cdk/pipelines/lib/main/pipeline-base.ts
@@ -2,6 +2,8 @@ import { Aspects, Stage } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { AddStageOpts as StageOptions, WaveOptions, Wave, IFileSetProducer, ShellStep, FileSet } from '../blueprint';
 
+const PIPELINE_SYMBOL = Symbol.for('@aws-cdk/pipelines.PipelineBase');
+
 /**
  * Properties for a `Pipeline`
  */
@@ -32,6 +34,15 @@ export interface PipelineBaseProps {
  * happens first).
  */
 export abstract class PipelineBase extends Construct {
+  /**
+   * Return whether the given object extends {@link PipelineBase}.
+   *
+   * We do attribute detection since we can't reliably use 'instanceof'.
+   */
+  public static isPipeline(x: any): x is PipelineBase {
+    return x !== null && typeof (x) === 'object' && PIPELINE_SYMBOL in x;
+  }
+
   /**
    * The build step that produces the CDK Cloud Assembly
    */
@@ -54,6 +65,8 @@ export abstract class PipelineBase extends Construct {
   constructor(scope: Construct, id: string, props: PipelineBaseProps) {
     super(scope, id);
 
+    Object.defineProperty(this, PIPELINE_SYMBOL, { value: true });
+
     if (props.synth instanceof ShellStep && !props.synth.primaryOutput) {
       props.synth.primaryOutputDirectory('cdk.out');
     }
diff --git a/packages/@aws-cdk/pipelines/test/main/pipeline-base.test.ts b/packages/@aws-cdk/pipelines/test/main/pipeline-base.test.ts
new file mode 100644
index 0000000000000..680f33f7dc602
--- /dev/null
+++ b/packages/@aws-cdk/pipelines/test/main/pipeline-base.test.ts
@@ -0,0 +1,29 @@
+import * as cdk from '@aws-cdk/core';
+import { Construct } from 'constructs';
+import { App } from '../../../core/lib';
+import { PipelineBase, IFileSetProducer, FileSet } from '../../lib';
+import { PIPELINE_ENV } from '../testhelpers';
+
+describe('pipeline base', () => {
+
+  test('PipelineBase.isPipeline indicates that a construct extends PipelineBase', () => {
+    const app = new App();
+    const pipelineStack = new cdk.Stack(app, 'PipelineStack', { env: PIPELINE_ENV });
+    const construct = new Construct(pipelineStack, 'Construct');
+    const pipeline = new class extends PipelineBase {
+      constructor() {
+        super(pipelineStack, 'Pipeline', {
+          synth: new class implements IFileSetProducer {
+            public readonly primaryOutput = new FileSet('PrimaryOutput');
+          }(),
+        });
+      }
+      protected doBuildPipeline(): void { }
+    }();
+
+    expect(PipelineBase.isPipeline(pipelineStack)).toStrictEqual(false);
+    expect(PipelineBase.isPipeline(construct)).toStrictEqual(false);
+    expect(PipelineBase.isPipeline(pipeline)).toStrictEqual(true);
+  });
+
+});
\ No newline at end of file