diff --git a/packages/compiler-cli/ngcc/src/execution/cluster/lock_file_with_child_process.ts b/packages/compiler-cli/ngcc/src/execution/cluster/lock_file_with_child_process.ts
new file mode 100644
index 0000000000000..b6354976a6cb1
--- /dev/null
+++ b/packages/compiler-cli/ngcc/src/execution/cluster/lock_file_with_child_process.ts
@@ -0,0 +1,42 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/// <reference types="node" />
+
+import {ChildProcess} from 'child_process';
+import * as cluster from 'cluster';
+
+import {AbsoluteFsPath} from '../../../../src/ngtsc/file_system';
+import {LockFileWithChildProcess} from '../../locking/lock_file_with_child_process';
+
+
+/**
+ * A `LockFileWithChildProcess` that is `cluster`-aware and does not spawn unlocker processes from
+ * worker processes (only from the master process, which does the locking).
+ */
+export class ClusterLockFileWithChildProcess extends LockFileWithChildProcess {
+  write(): void {
+    if (!cluster.isMaster) {
+      // This is a worker process:
+      // This method should only be on the master process.
+      throw new Error('Tried to create a lock-file from a worker process.');
+    }
+
+    return super.write();
+  }
+
+  protected createUnlocker(path: AbsoluteFsPath): ChildProcess|null {
+    if (cluster.isMaster) {
+      // This is the master process:
+      // Create the unlocker.
+      return super.createUnlocker(path);
+    }
+
+    return null;
+  }
+}
diff --git a/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts b/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts
index cbabff7719db4..a544addf0dd9e 100644
--- a/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts
+++ b/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/index.ts
@@ -5,7 +5,8 @@
  * Use of this source code is governed by an MIT-style license that can be
  * found in the LICENSE file at https://angular.io/license
  */
-import {ChildProcess, fork} from 'child_process';
+import {ChildProcess, ChildProcessByStdio, fork} from 'child_process';
+import {Readable, Writable} from 'stream';
 
 import {AbsoluteFsPath, CachedFileSystem, FileSystem} from '../../../../src/ngtsc/file_system';
 import {Logger, LogLevel} from '../../logging/logger';
@@ -77,10 +78,18 @@ export class LockFileWithChildProcess implements LockFile {
     }
   }
 
-  protected createUnlocker(path: AbsoluteFsPath): ChildProcess {
+  protected createUnlocker(path: AbsoluteFsPath): ChildProcess|null {
     this.logger.debug('Forking unlocker child-process');
     const logLevel =
         this.logger.level !== undefined ? this.logger.level.toString() : LogLevel.info.toString();
-    return fork(this.fs.resolve(__dirname, './unlocker.js'), [path, logLevel], {detached: true});
+
+    const unlocker = fork(this.fs.resolve(__dirname, './unlocker.js'), [path, logLevel], {
+                       detached: true,
+                       stdio: 'pipe',
+                     }) as ChildProcessByStdio<Writable, Readable, Readable>;
+    unlocker.stdout.on('data', data => process.stdout.write(data));
+    unlocker.stderr.on('data', data => process.stderr.write(data));
+
+    return unlocker;
   }
 }
diff --git a/packages/compiler-cli/ngcc/src/main.ts b/packages/compiler-cli/ngcc/src/main.ts
index 1f63a029bbbf7..0d072866a1ce6 100644
--- a/packages/compiler-cli/ngcc/src/main.ts
+++ b/packages/compiler-cli/ngcc/src/main.ts
@@ -27,6 +27,7 @@ import {EntryPointFinder} from './entry_point_finder/interface';
 import {TargetedEntryPointFinder} from './entry_point_finder/targeted_entry_point_finder';
 import {AnalyzeEntryPointsFn, CreateCompileFn, Executor} from './execution/api';
 import {ClusterExecutor} from './execution/cluster/executor';
+import {ClusterLockFileWithChildProcess} from './execution/cluster/lock_file_with_child_process';
 import {ClusterPackageJsonUpdater} from './execution/cluster/package_json_updater';
 import {SingleProcessExecutorAsync, SingleProcessExecutorSync} from './execution/single_process_executor';
 import {CreateTaskCompletedCallback, PartiallyOrderedTasks, Task, TaskProcessingOutcome, TaskQueue} from './execution/tasks/api';
@@ -428,7 +429,8 @@ function getCreateTaskCompletedCallback(
 function getExecutor(
     async: boolean, inParallel: boolean, logger: Logger, pkgJsonUpdater: PackageJsonUpdater,
     fileSystem: FileSystem, createTaskCompletedCallback: CreateTaskCompletedCallback): Executor {
-  const lockFile = new LockFileWithChildProcess(fileSystem, logger);
+  const lockFile = inParallel ? new ClusterLockFileWithChildProcess(fileSystem, logger) :
+                                new LockFileWithChildProcess(fileSystem, logger);
   if (async) {
     // Execute asynchronously (either serially or in parallel)
     const locker = new AsyncLocker(lockFile, logger, 500, 50);
diff --git a/packages/compiler-cli/ngcc/test/execution/cluster/lock_file_with_child_process_spec.ts b/packages/compiler-cli/ngcc/test/execution/cluster/lock_file_with_child_process_spec.ts
new file mode 100644
index 0000000000000..17501508d5c05
--- /dev/null
+++ b/packages/compiler-cli/ngcc/test/execution/cluster/lock_file_with_child_process_spec.ts
@@ -0,0 +1,87 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+/// <reference types="node" />
+
+import {ChildProcess} from 'child_process';
+import * as cluster from 'cluster';
+
+import {getFileSystem} from '../../../../src/ngtsc/file_system';
+import {runInEachFileSystem} from '../../../../src/ngtsc/file_system/testing';
+import {ClusterLockFileWithChildProcess} from '../../../src/execution/cluster/lock_file_with_child_process';
+import {LockFileWithChildProcess} from '../../../src/locking/lock_file_with_child_process';
+import {MockLogger} from '../../helpers/mock_logger';
+import {mockProperty} from '../../helpers/spy_utils';
+
+
+runInEachFileSystem(() => {
+  describe('ClusterLockFileWithChildProcess', () => {
+    const runAsClusterMaster = mockProperty(cluster, 'isMaster');
+    const mockUnlockerProcess = {} as ChildProcess;
+    let lockFileWithChildProcessSpies:
+        Record<'createUnlocker'|'read'|'remove'|'write', jasmine.Spy>;
+
+    beforeEach(() => {
+      lockFileWithChildProcessSpies = {
+        createUnlocker: spyOn(LockFileWithChildProcess.prototype as any, 'createUnlocker')
+                            .and.returnValue(mockUnlockerProcess),
+        read: spyOn(LockFileWithChildProcess.prototype, 'read').and.returnValue('{unknown}'),
+        remove: spyOn(LockFileWithChildProcess.prototype, 'remove'),
+        write: spyOn(LockFileWithChildProcess.prototype, 'write'),
+      };
+    });
+
+    it('should be an instance of `LockFileWithChildProcess`', () => {
+      const lockFile = new ClusterLockFileWithChildProcess(getFileSystem(), new MockLogger());
+
+      expect(lockFile).toEqual(jasmine.any(ClusterLockFileWithChildProcess));
+      expect(lockFile).toEqual(jasmine.any(LockFileWithChildProcess));
+    });
+
+    describe('write()', () => {
+      it('should create the lock-file when called on the cluster master', () => {
+        runAsClusterMaster(true);
+        const lockFile = new ClusterLockFileWithChildProcess(getFileSystem(), new MockLogger());
+
+        expect(lockFileWithChildProcessSpies.write).not.toHaveBeenCalled();
+
+        lockFile.write();
+        expect(lockFileWithChildProcessSpies.write).toHaveBeenCalledWith();
+      });
+
+      it('should throw an error when called on a cluster worker', () => {
+        runAsClusterMaster(false);
+        const lockFile = new ClusterLockFileWithChildProcess(getFileSystem(), new MockLogger());
+
+        expect(() => lockFile.write())
+            .toThrowError('Tried to create a lock-file from a worker process.');
+        expect(lockFileWithChildProcessSpies.write).not.toHaveBeenCalled();
+      });
+    });
+
+    describe('createUnlocker()', () => {
+      it('should create the unlocker when called on the cluster master', () => {
+        runAsClusterMaster(true);
+        const lockFile = new ClusterLockFileWithChildProcess(getFileSystem(), new MockLogger());
+
+        lockFileWithChildProcessSpies.createUnlocker.calls.reset();
+
+        expect((lockFile as any).createUnlocker(lockFile.path)).toBe(mockUnlockerProcess);
+        expect(lockFileWithChildProcessSpies.createUnlocker).toHaveBeenCalledWith(lockFile.path);
+      });
+
+      it('should not create the unlocker when called on a cluster worker', () => {
+        runAsClusterMaster(false);
+        const lockFile = new ClusterLockFileWithChildProcess(getFileSystem(), new MockLogger());
+
+        expect((lockFile as any).createUnlocker(lockFile.path)).toBeNull();
+        expect(lockFileWithChildProcessSpies.createUnlocker).not.toHaveBeenCalled();
+      });
+    });
+  });
+});