Error when deploy Spring Boot application in Google AppEngine + Non Zero Exit 2 - spring-boot

Question

I am getting below error when deploying my test maven Spring Boot REST app in GAE -
[ERROR] Failed to execute goal com.google.cloud.tools:appengine-maven-plugin:2.0.0-rc5:deploy (default-cli) on project PublicLibrary: App Engine application deployment failed: com.google.cloud.tools.appengine.operations.cloudsdk.process.ProcessHandlerException: com.google.cloud.tools.appengine.AppEngineException: Non zero exit: 2 -> [Help 1]
App.yaml looks like
runtime: java
env: flex
runtime_config:
jdk: openjdk8
env_variables:
SPRING_PROFILES_ACTIVE: "gcp"
handlers:
- url: /.*
script: this field is required, but ignored
manual_scaling:
instances: 1
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.publiclibrary</groupId>
<artifactId>PublicLibrary</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>PublicLibrary</name>
<description>Demo project for Spring data relationship</description>
<properties>
<java.version>1.8</java.version>
</properties>
<profiles>
<profile>
<id>cloud-gcp</id>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-gcp-starter</artifactId>
<version>1.0.0.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>2.0.0-rc5</version>
<configuration>
<deploy.projectId>libraryapi-03312019</deploy.projectId>
<deploy.version>1.0</deploy.version>
</configuration>
</plugin>
</plugins>
</build>
</profile>
</profiles>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-rest</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-validation</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>25.0-jre</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.assertj</groupId>
<artifactId>assertj-core</artifactId>
</exclusion>
</exclusions>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
I would appreciate any help.

Answer 1

Check the official Springboot sample of Google Cloud Platform to see what you might be doing different.
For example, I see that in the <properties> section it requires <maven.compiler.source> and <maven.compiler.target>:
<properties>
<java.version>1.8</java.version>
<maven.compiler.source>${java.version}</maven.compiler.source> <!-- REQUIRED -->
<maven.compiler.target>${java.version}</maven.compiler.target> <!-- REQUIRED -->
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<appengine.maven.plugin>1.3.2</appengine.maven.plugin>
</properties>
Note that you are using version 2.0.0-rc5 for the appengine-maven-plugin so if you add it in the properties like above you should use the same version as in the plugin section:
<plugin>
<groupId>com.google.cloud.tools</groupId>
<artifactId>appengine-maven-plugin</artifactId>
<version>${appengine.maven.plugin}</version>
</plugin>

Answer 2

Thanks. I followed the sample app and add the differences to my pom.xml. That alone didn't fix the issue. Additionally, I added legacy health checks that to app.yaml that allowed to deploy the app (which took quite some time) -
health_check:
enable_health_check: True
check_interval_sec: 5
timeout_sec: 4
unhealthy_threshold: 2
healthy_threshold: 2
But after deployment when I try to access the app as https://< project-id>:appspot.com I get below error -
Error: Server Error
The server encountered a temporary error and could not complete your request.
Please try again in 30 seconds.
UPDATE
I added the resources section to app.yaml as in GAE Java is known to consume high memory as identified in this article
resources:
cpu: 2
memory_gb: 2.3
disk_size_gb: 10
volumes:
- name: ramdisk1
volume_type: tmpfs
size_gb: 0.5