Run Android emulator without GUI (headless Android)

Android Emulator 28.1.8 now supports running the emulator in headless mode (emulator-headless): https://androidstudio.googleblog.com/2019/02/emulator-2818-canary.html

As of 29.2.11, you need to use the -no-window option instead of the emulator-headless binary:

The binary emulator-headless is now retired. Headless builds of the engine are now launched via emulator -no-window, thus unifying the previously separate (but similar) paths.

https://androidstudio.googleblog.com/2019/12/emulator-29211-and-amd-hypervisor-12-to.html

One of the options to achieve that is to stop zygote service when an emulator running. When stopping the zygote process (aka app_process) all of the system services, that were forked from zygote at system boot, shuts down. Only a few native system services will be running. The emulator's display should show the startup logo (or animation).

The steps for stopping zygote are as follows:

• adb shell
• su (most of emulator images have /system/xbin/su)
• stop zygote

After that you can explore how less services are running with service list. Critical for Android Runtime services will be stopped, e.g.

activity: [] // ActivityManager
package: [] // PackageManager
display: [] // DisplayManager
...

To start zygote execute:

• start zygote

Note: with the @CommonsWare's solution you are still going to have zygote and most of the Android system services running.