O erro é:
Failed to launch emulator. Reason: No emulators found as an output of `emulator -list-avds`.
Completo:
react-native run-android
info Running jetifier to migrate libraries to AndroidX. You can disable it using "--no-jetifier" flag.
Jetifier found 864 file(s) to forward-jetify. Using 4 workers...
info JS server already running.
/bin/sh: 1: adb: not found
info Launching emulator...
error Failed to launch emulator. Reason: No emulators found as an output of `emulator -list-avds`.
warn Please launch an emulator manually or connect a device. Otherwise app may fail to launch.
info Installing the app...
FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring project ':app'.
> SDK location not found. Define location with an ANDROID_SDK_ROOT environment variable or by setting the sdk.dir path in your project's local properties file at '/var/www/html/react-native/InstaAluraMobile/android/local.properties'.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 8s
error Failed to install the app. Make sure you have the Android development environment set up: https://facebook.github.io/react-native/docs/getting-started.html#android-development-environment. Run CLI with --verbose flag for more details.
Error: Command failed: ./gradlew app:installDebug -PreactNativeDevServerPort=8081
FAILURE: Build failed with an exception.
* What went wrong:
A problem occurred configuring project ':app'.
> SDK location not found. Define location with an ANDROID_SDK_ROOT environment variable or by setting the sdk.dir path in your project's local properties file at '/var/www/html/react-native/InstaAluraMobile/android/local.properties'.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 8s
at checkExecSyncError (child_process.js:629:11)
at execFileSync (child_process.js:647:13)
at runOnAllDevices (/var/www/html/react-native/InstaAluraMobile/node_modules/@react-native-community/cli-platform-android/build/commands/runAndroid/runOnAllDevices.js:94:39)
at process._tickCallback (internal/process/next_tick.js:68:7)