Cloud Native Buildpacks Tutorial - 2.2. ┗ gcr.io/paketo-buildpacks/builder:base BuilderでJavaアプリ(Servlet)のOCIイメージを作成
gcr.io/paketo-buildpacks/builder:baseでJava(Servlet)のアプリケーションのOCIイメージを作成します。
BuilderとStackを予めpullしておいてください。
docker pull gcr.io/paketo-buildpacks/builder:base
docker pull gcr.io/paketo-buildpacks/run:base-cnb
次のコマンドで"Hello World"アプリケーションを作成します。
mkdir -p hello-servlet/src/main/java/hello
cd hello-servlet
cat <<'EOF' > src/main/java/hello/HelloServlet.java
package hello;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet(name = "hello", urlPatterns = "/")
public class HelloServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException {
res.setContentType("text/plain;charset=utf-8");
PrintWriter pw = res.getWriter();
pw.print("Hello World!");
pw.flush();
}
}
EOF
cat <<'EOF' > 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>
<groupId>hello</groupId>
<artifactId>hello-servlet</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>war</packaging>
<properties>
<maven.compiler.source>11</maven.compiler.source>
<maven.compiler.target>11</maven.compiler.target>
<failOnMissingWebXml>false</failOnMissingWebXml>
</properties>
<dependencies>
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>javax.servlet-api</artifactId>
<version>4.0.1</version>
<scope>provided</scope>
</dependency>
</dependencies>
</project>
EOF
pack buildコマンドでイメージを作成します。
Javaの場合はソースからビルドする方法とjar/warファイルからビルドする方法があります。
ソースからビルドする場合
pack build making/pack-servlet --no-pull --builder gcr.io/paketo-buildpacks/builder:base
BuilderとStackを事前にpullしていない場合は
--no-pullを外せば、ビルド時にBuilderとStackもpullしますが、ビルドが遅くなります。
次のようなログが出力されます。
===> DETECTING
[detector] 6 of 15 buildpacks participating
[detector] paketo-buildpacks/bellsoft-liberica 2.5.3
[detector] paketo-buildpacks/maven 1.2.2
[detector] paketo-buildpacks/executable-jar 1.2.3
[detector] paketo-buildpacks/apache-tomcat 1.1.3
[detector] paketo-buildpacks/dist-zip 1.3.0
[detector] paketo-buildpacks/spring-boot 1.5.3
===> ANALYZING
[analyzer] Previous image with name "index.docker.io/making/pack-servlet:latest" not found
===> RESTORING
===> BUILDING
[builder]
[builder] Paketo BellSoft Liberica Buildpack 2.5.3
[builder] Set $BPL_JVM_HEAD_ROOM to configure the headroom in memory calculation. Default 0.
[builder] Set $BPL_JVM_LOADED_CLASS_COUNT to configure the number of loaded classes in memory calculation. Default 35% of classes.
[builder] Set $BPL_JVM_THREAD_COUNT to configure the number of threads in memory calculation. Default 250.
[builder] Set $BP_JVM_VERSION to configure the Java version. Default 11.*.
[builder] BellSoft Liberica JDK 11.0.7: Contributing to layer
[builder] Downloading from https://github.com/bell-sw/Liberica/releases/download/11.0.7+10/bellsoft-jdk11.0.7+10-linux-amd64.tar.gz
[builder] Verifying checksum
[builder] Expanding to /layers/paketo-buildpacks_bellsoft-liberica/jdk
[builder] Populating with 133 container certificates
[builder] Writing env.build/JAVA_HOME.override
[builder] Writing env.build/JDK_HOME.override
[builder] BellSoft Liberica JRE 11.0.7: Contributing to layer
[builder] Downloading from https://github.com/bell-sw/Liberica/releases/download/11.0.7+10/bellsoft-jre11.0.7+10-linux-amd64.tar.gz
[builder] Verifying checksum
[builder] Expanding to /layers/paketo-buildpacks_bellsoft-liberica/jre
[builder] Writing env.launch/JAVA_HOME.override
[builder] Writing env.launch/MALLOC_ARENA_MAX.override
[builder] Writing profile.d/active-processor-count.sh
[builder] Memory Calculator 4.0.0: Contributing to layer
[builder] Downloading from https://github.com/cloudfoundry/java-buildpack-memory-calculator/releases/download/v4.0.0/memory-calculator-4.0.0.tgz
[builder] Verifying checksum
[builder] Expanding to /layers/paketo-buildpacks_bellsoft-liberica/memory-calculator
[builder] Writing profile.d/memory-calculator.sh
[builder] Class Counter: Contributing to layer
[builder] Copying to /layers/paketo-buildpacks_bellsoft-liberica/class-counter
[builder] JVMKill Agent 1.16.0: Contributing to layer
[builder] Downloading from https://github.com/cloudfoundry/jvmkill/releases/download/v1.16.0.RELEASE/jvmkill-1.16.0-RELEASE.so
[builder] Verifying checksum
[builder] Copying to /layers/paketo-buildpacks_bellsoft-liberica/jvmkill
[builder] Writing env.launch/JAVA_OPTS.append
[builder] Link-Local DNS: Contributing to layer
[builder] Copying to /layers/paketo-buildpacks_bellsoft-liberica/link-local-dns
[builder] Writing profile.d/link-local-dns.sh
[builder] Java Security Properties: Contributing to layer
[builder] Writing env.launch/JAVA_OPTS.append
[builder] Writing env.launch/JAVA_SECURITY_PROPERTIES.override
[builder] Security Providers Configurer: Contributing to layer
[builder] Copying to /layers/paketo-buildpacks_bellsoft-liberica/security-providers-configurer
[builder] Writing profile.d/security-providers-classpath.sh
[builder] Writing profile.d/security-providers-configurer.sh
[builder] OpenSSL Security Provider 1.0.2: Contributing to layer
[builder] Downloading from https://jitpack.io/com/github/paketo-buildpacks/openssl-security-provider/1.0.2/openssl-security-provider-1.0.2.jar
[builder] Verifying checksum
[builder] Copying to /layers/paketo-buildpacks_bellsoft-liberica/openssl-security-provider
[builder] Writing env.launch/SECURITY_PROVIDERS.append
[builder] Writing env.launch/SECURITY_PROVIDERS_CLASSPATH
[builder] Writing profile.d/openssl-security-provider.sh
[builder]
[builder] Paketo Maven Buildpack 1.2.2
[builder] Set $BP_MAVEN_BUILD_ARGUMENTS to configure the arguments to pass to Maven. Default -Dmaven.test.skip=true package.
[builder] Set $BP_MAVEN_BUILT_ARTIFACT to configure the built application artifact explicitly. Supersedes $BP_MAVEN_BUILT_MODULE. Default target/*.[jw]ar.
[builder] Set $BP_MAVEN_BUILT_MODULE to configure the module to find application artifact in
[builder] Set $BP_MAVEN_SETTINGS to configure the contents of a `settings.xml` file to be used at build time
[builder] Apache Maven 3.6.3: Contributing to layer
[builder] Downloading from https://repo1.maven.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.tar.gz
[builder] Verifying checksum
[builder] Expanding to /layers/paketo-buildpacks_maven/maven
[builder] Creating cache directory /home/cnb/.m2
[builder] Compiled Application: Contributing to layer
[builder] Executing mvn -Dmaven.test.skip=true package
[builder] [INFO] Scanning for projects...
[builder] [INFO]
[builder] [INFO] ------------------------< hello:hello-servlet >-------------------------
[builder] [INFO] Building hello-servlet 0.0.1-SNAPSHOT
[builder] [INFO] --------------------------------[ war ]---------------------------------
[builder] Downloading from central: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-resources-plugin/2.6/maven-resources-plugin-2.6.pom
Downloaded from central: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-resources-plugin/2.6/maven-resources-plugin-2.6.pom (8.1 kB at 8.2 kB/s)
[builder] Downloading from central: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-plugins/23/maven-plugins-23.pom
Downloaded from central: https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-plugins/23/maven-plugins-23.pom (9.2 kB at 33 kB/s)
[builder] Downloading from central: https://repo.maven.apache.org/maven2/org/apache/maven/maven-parent/22/maven-parent-22.pom
..(略)..
[builder] [INFO] Webapp assembled in [24 msecs]
[builder] [INFO] Building war: /workspace/target/hello-servlet-0.0.1-SNAPSHOT.war
[builder] [INFO] ------------------------------------------------------------------------
[builder] [INFO] BUILD SUCCESS
[builder] [INFO] ------------------------------------------------------------------------
[builder] [INFO] Total time: 01:05 min
[builder] [INFO] Finished at: 2020-05-11T02:21:26Z
[builder] [INFO] ------------------------------------------------------------------------
[builder] Removing source code
[builder]
[builder] Paketo Apache Tomcat Buildpack 1.1.3
[builder] Set $BPL_TOMCAT_ACCESS_LOGGING to configure the Tomcat access logging state. Default disabled.
[builder] Set $BP_TOMCAT_CONTEXT_PATH to configure the application context path
[builder] Set $BP_TOMCAT_EXT_CONF_SHA256 to configure the SHA256 hash of the external Tomcat configuration archive
[builder] Set $BP_TOMCAT_EXT_CONF_STRIP to configure the number of directory components to strip from the external Tomcat configuration archive. Default 0.
[builder] Set $BP_TOMCAT_EXT_CONF_URI to configure the download location of the external Tomcat configuration
[builder] Set $BP_TOMCAT_EXT_CONF_VERSION to configure the version of the external Tomcat configuration
[builder] Set $BP_TOMCAT_VERSION to configure the Tomcat version. Default 9.*.
[builder] Apache Tomcat 9.0.34: Contributing to layer
[builder] Downloading from https://archive.apache.org/dist/tomcat/tomcat-9/v9.0.34/bin/apache-tomcat-9.0.34.tar.gz
[builder] Verifying checksum
[builder] Expanding to /layers/paketo-buildpacks_apache-tomcat/catalina-home
[builder] Writing env.launch/CATALINA_HOME.override
[builder] Apache Tomcat Support: Contributing to layer
[builder] Copying context.xml to /layers/paketo-buildpacks_apache-tomcat/catalina-base/conf
[builder] Copying logging.properties to /layers/paketo-buildpacks_apache-tomcat/catalina-base/conf
[builder] Copying server.xml to /layers/paketo-buildpacks_apache-tomcat/catalina-base/conf
[builder] Copying web.xml to /layers/paketo-buildpacks_apache-tomcat/catalina-base/conf
[builder] Apache Tomcat Access Logging Support 3.3.0
[builder] Downloading from https://repo.spring.io/release/org/cloudfoundry/tomcat-access-logging-support/3.3.0.RELEASE/tomcat-access-logging-support-3.3.0.RELEASE.jar
[builder] Verifying checksum
[builder] Copying to /layers/paketo-buildpacks_apache-tomcat/catalina-base/lib
[builder] Apache Tomcat Lifecycle Support 3.3.0
[builder] Downloading from https://repo.spring.io/release/org/cloudfoundry/tomcat-lifecycle-support/3.3.0.RELEASE/tomcat-lifecycle-support-3.3.0.RELEASE.jar
[builder] Verifying checksum
[builder] Copying to /layers/paketo-buildpacks_apache-tomcat/catalina-base/lib
[builder] Apache Tomcat Logging Support 3.3.0
[builder] Downloading from https://repo.spring.io/release/org/cloudfoundry/tomcat-logging-support/3.3.0.RELEASE/tomcat-logging-support-3.3.0.RELEASE.jar
[builder] Verifying checksum
[builder] Copying to /layers/paketo-buildpacks_apache-tomcat/catalina-base/bin
[builder] Writing /layers/paketo-buildpacks_apache-tomcat/catalina-base/bin/setenv.sh
[builder] Mounting application at ROOT
[builder] Writing env.launch/CATALINA_BASE.override
[builder] Writing profile.d/access-logging-support.sh
[builder] Process types:
[builder] task: catalina.sh run
[builder] tomcat: catalina.sh run
[builder] web: catalina.sh run
===> EXPORTING
[exporter] Adding layer 'launcher'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:class-counter'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:java-security-properties'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:jre'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:jvmkill'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:link-local-dns'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:memory-calculator'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:openssl-security-provider'
[exporter] Adding layer 'paketo-buildpacks/bellsoft-liberica:security-providers-configurer'
[exporter] Adding layer 'paketo-buildpacks/apache-tomcat:catalina-base'
[exporter] Adding layer 'paketo-buildpacks/apache-tomcat:catalina-home'
[exporter] Adding 1/1 app layer(s)
[exporter] Adding layer 'config'
[exporter] *** Images (5471273d1b79):
[exporter] index.docker.io/making/pack-servlet:latest
[exporter] Adding cache layer 'paketo-buildpacks/bellsoft-liberica:jdk'
[exporter] Adding cache layer 'paketo-buildpacks/maven:application'
[exporter] Adding cache layer 'paketo-buildpacks/maven:cache'
[exporter] Adding cache layer 'paketo-buildpacks/maven:maven'
Successfully built image making/pack-servlet
pack build時に--publishオプションをつけると、Docker Registryでのpushを行います。事前にdocker loginが必要です。
Mavenによるソースコードから始まるため、初回ビルド時には依存ライブラリのダウンロードが始まります。 依存ライブラリはキャッシュされ、二回目以降はキャッシュが使用されます。
- JDKのバージョンはビルド時に環境変数
$BP_JVM_VERSIONを設定することで指定できます。デフォルトは11.*です。(例:-e BP_JVM_VERSION=8.*)- Tomcatのバージョンはビルド時に環境変数
BP_TOMCAT_VERSIONを設定することで指定できます。デフォルトは9.*です。(例:-e BP_TOMCAT_VERSION=8.5.*)
pack inspect-imageでイメージを解析します。
$ pack inspect-image making/pack-servlet
REMOTE:
(not present)
LOCAL:
Stack: io.buildpacks.stacks.bionic
Base Image:
Reference: 5b753a27144e7034add3089565bd3a18a4e5790efce0c9771d2ed4bb40d6fc60
Top Layer: sha256:2d0a8ddecbd1b537f555a120356f4dc9ff5855b2aa16b9d0edd7f9b5c3f9ade6
Run Images:
gcr.io/paketo-buildpacks/run:base-cnb
Buildpacks:
ID VERSION
paketo-buildpacks/bellsoft-liberica 2.5.3
paketo-buildpacks/maven 1.2.2
paketo-buildpacks/executable-jar 1.2.3
paketo-buildpacks/apache-tomcat 1.1.3
paketo-buildpacks/dist-zip 1.3.0
paketo-buildpacks/spring-boot 1.5.3
Processes:
TYPE SHELL COMMAND ARGS
web (default) bash catalina.sh run
task bash catalina.sh run
tomcat bash catalina.sh run
Maven以外にもGradleによるビルドもサポートされています。
warからビルドする場合
まずはソースコードをビルドしてwarファイルを作成します。
mvn -Dmaven.test.skip=true clean package
pack buildの-pオプションで作成したwarファイルのパスを指定します。
pack build making/pack-servlet --no-pull -p target/hello-servlet-0.0.1-SNAPSHOT.war --builder gcr.io/paketo-buildpacks/builder:base
次のようなログが出力されます。
===> DETECTING
[detector] 4 of 15 buildpacks participating
[detector] paketo-buildpacks/bellsoft-liberica 2.5.3
[detector] paketo-buildpacks/apache-tomcat 1.1.3
[detector] paketo-buildpacks/dist-zip 1.3.0
[detector] paketo-buildpacks/spring-boot 1.5.3
===> ANALYZING
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:openssl-security-provider" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:security-providers-configurer" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:class-counter" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:java-security-properties" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:jre" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:jvmkill" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:link-local-dns" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/bellsoft-liberica:memory-calculator" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/apache-tomcat:catalina-base" from app image
[analyzer] Restoring metadata for "paketo-buildpacks/apache-tomcat:catalina-home" from app image
===> RESTORING
===> BUILDING
[builder]
[builder] Paketo BellSoft Liberica Buildpack 2.5.3
[builder] Set $BPL_JVM_HEAD_ROOM to configure the headroom in memory calculation. Default 0.
[builder] Set $BPL_JVM_LOADED_CLASS_COUNT to configure the number of loaded classes in memory calculation. Default 35% of classes.
[builder] Set $BPL_JVM_THREAD_COUNT to configure the number of threads in memory calculation. Default 250.
[builder] Set $BP_JVM_VERSION to configure the Java version. Default 11.*.
[builder] BellSoft Liberica JRE 11.0.7: Reusing cached layer
[builder] Memory Calculator 4.0.0: Reusing cached layer
[builder] Class Counter: Reusing cached layer
[builder] JVMKill Agent 1.16.0: Reusing cached layer
[builder] Link-Local DNS: Reusing cached layer
[builder] Java Security Properties: Reusing cached layer
[builder] Security Providers Configurer: Reusing cached layer
[builder] OpenSSL Security Provider 1.0.2: Reusing cached layer
[builder]
[builder] Paketo Apache Tomcat Buildpack 1.1.3
[builder] Set $BPL_TOMCAT_ACCESS_LOGGING to configure the Tomcat access logging state. Default disabled.
[builder] Set $BP_TOMCAT_CONTEXT_PATH to configure the application context path
[builder] Set $BP_TOMCAT_EXT_CONF_SHA256 to configure the SHA256 hash of the external Tomcat configuration archive
[builder] Set $BP_TOMCAT_EXT_CONF_STRIP to configure the number of directory components to strip from the external Tomcat configuration archive. Default 0.
[builder] Set $BP_TOMCAT_EXT_CONF_URI to configure the download location of the external Tomcat configuration
[builder] Set $BP_TOMCAT_EXT_CONF_VERSION to configure the version of the external Tomcat configuration
[builder] Set $BP_TOMCAT_VERSION to configure the Tomcat version. Default 9.*.
[builder] Apache Tomcat 9.0.34: Reusing cached layer
[builder] Apache Tomcat Support: Reusing cached layer
[builder] Process types:
[builder] task: catalina.sh run
[builder] tomcat: catalina.sh run
[builder] web: catalina.sh run
===> EXPORTING
[exporter] Reusing layer 'launcher'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:class-counter'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:java-security-properties'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:jre'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:jvmkill'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:link-local-dns'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:memory-calculator'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:openssl-security-provider'
[exporter] Reusing layer 'paketo-buildpacks/bellsoft-liberica:security-providers-configurer'
[exporter] Reusing layer 'paketo-buildpacks/apache-tomcat:catalina-base'
[exporter] Reusing layer 'paketo-buildpacks/apache-tomcat:catalina-home'
[exporter] Adding 1/1 app layer(s)
[exporter] Adding layer 'config'
[exporter] *** Images (f18b05e6c3be):
[exporter] index.docker.io/making/pack-servlet:latest
Successfully built image making/pack-servlet
今回はイメージビルド時にMavenによるビルドは実行されません。
- JDKのバージョンはビルド時に環境変数
BP_JVM_VERSIONを設定することで指定できます。デフォルトは11.*です。(例:-e BP_JVM_VERSION=8.*)
pack inspect-imageでイメージを解析します。
$ pack inspect-image making/pack-servlet
Inspecting image: making/pack-servlet
REMOTE:
(not present)
LOCAL:
Stack: io.buildpacks.stacks.bionic
Base Image:
Reference: 5b753a27144e7034add3089565bd3a18a4e5790efce0c9771d2ed4bb40d6fc60
Top Layer: sha256:2d0a8ddecbd1b537f555a120356f4dc9ff5855b2aa16b9d0edd7f9b5c3f9ade6
Run Images:
gcr.io/paketo-buildpacks/run:base-cnb
Buildpacks:
ID VERSION
paketo-buildpacks/bellsoft-liberica 2.5.3
paketo-buildpacks/apache-tomcat 1.1.3
paketo-buildpacks/dist-zip 1.3.0
paketo-buildpacks/spring-boot 1.5.3
Processes:
TYPE SHELL COMMAND ARGS
web (default) bash catalina.sh run
task bash catalina.sh run
tomcat bash catalina.sh run
イメージの実行
作成したイメージをdocker runで起動します。
docker run --rm -p 8080:8080 making/pack-servlet
起動時に次のようなログが出力されます。
Container memory limit unset. Configuring JVM for 1G container.
Calculated JVM Memory Configuration: -XX:MaxDirectMemorySize=10M -XX:MaxMetaspaceSize=61686K -XX:ReservedCodeCacheSize=240M -Xss1M -Xmx474889K (Head Room: 0%, Loaded Class Count: 8477, Thread Count: 250, Total Memory: 1073741824)
NOTE: Picked up JDK_JAVA_OPTIONS: --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.io=ALL-UNNAMED --add-opens=java.rmi/sun.rmi.transport=ALL-UNNAMED
[CONTAINER] org.apache.coyote.http11.Http11NioProtocol INFO Initializing ProtocolHandler ["http-nio-8080"]
[CONTAINER] org.apache.catalina.startup.Catalina INFO Server initialization in [568] milliseconds
[CONTAINER] org.apache.catalina.core.StandardService INFO Starting service [Catalina]
[CONTAINER] org.apache.catalina.core.StandardEngine INFO Starting Servlet engine: [Apache Tomcat/9.0.34]
[CONTAINER] org.apache.catalina.startup.HostConfig INFO Deploying web application directory [/layers/paketo-buildpacks_apache-tomcat/catalina-base/webapps/ROOT]
[CONTAINER] org.apache.jasper.servlet.TldScanner INFO At least one JAR was scanned for TLDs yet contained no TLDs. Enable debug logging for this logger for a complete list of JARs that were scanned but no TLDs were found in them. Skipping unneeded JARs during scanning can improve startup time and JSP compilation time.
[CONTAINER] org.apache.catalina.startup.HostConfig INFO Deployment of web application directory [/layers/paketo-buildpacks_apache-tomcat/catalina-base/webapps/ROOT] has finished in [290] ms
[CONTAINER] org.apache.coyote.http11.Http11NioProtocol INFO Starting ProtocolHandler ["http-nio-8080"]
[CONTAINER] org.apache.catalina.startup.Catalina INFO Server startup in [355] milliseconds
JVMのメモリが自動で設定されていることに注目してください。
アプリケーションにアクセスします。
$ curl localhost:8080 -w '\n'
Hello World!
Docker Imageのサイズを確認します。
$ docker images | grep making/pack-servlet
making/pack-servlet latest 562795acce7b 40 years ago 256MB
Java Buildpackの細かい設定は https://github.com/paketo-buildpacks/java を確認してください。
おわったらDocker Imageを削除します。
docker rmi making/pack-servlet