Deploy Java Lambda functions with container images
There are three ways to build a container image for a Java Lambda function:
-
Using an AWS base image for Java
The AWS base images are preloaded with a language runtime, a runtime interface client to manage the interaction between Lambda and your function code, and a runtime interface emulator for local testing.
-
Using an AWS OS-only base image
AWS OS-only base images
contain an Amazon Linux distribution and the runtime interface emulator . These images are commonly used to create container images for compiled languages, such as Go and Rust, and for a language or language version that Lambda doesn't provide a base image for, such as Node.js 19. You can also use OS-only base images to implement a custom runtime. To make the image compatible with Lambda, you must include the runtime interface client for Java in the image. -
You can use an alternative base image from another container registry, such as Alpine Linux or Debian. You can also use a custom image created by your organization. To make the image compatible with Lambda, you must include the runtime interface client for Java in the image.
Tip
To reduce the time it takes for Lambda container functions to become active, see Use multi-stage builds
This page explains how to build, test, and deploy container images for Lambda.
Topics
AWS base images for Java
AWS provides the following base images for Java:
Tags | Runtime | Operating system | Dockerfile | Deprecation |
---|---|---|---|---|
21 |
Java 21 | Amazon Linux 2023 | Dockerfile
for Java 21 on GitHub |
Not scheduled |
17 |
Java 17 | Amazon Linux 2 | Dockerfile
for Java 17 on GitHub |
Not scheduled |
11 |
Java 11 | Amazon Linux 2 | Dockerfile
for Java 11 on GitHub |
Not scheduled |
8.al2 |
Java 8 | Amazon Linux 2 | Dockerfile
for Java 8 on GitHub |
Not scheduled |
Amazon ECR repository: gallery.ecr.aws/lambda/java
The Java 21 and later base images are based on the Amazon Linux 2023 minimal container image. Earlier base images use Amazon Linux 2. AL2023 provides several advantages over Amazon Linux 2, including a smaller deployment footprint and updated versions of libraries such as glibc
.
AL2023-based images use microdnf
(symlinked as dnf
) as the package manager instead of yum
, which is the default package manager in Amazon Linux 2. microdnf
is a standalone implementation of dnf
. For a list of packages that are included in AL2023-based images, refer to the Minimal Container columns in Comparing packages installed on Amazon Linux 2023 Container Images. For more information about the differences between AL2023 and Amazon Linux 2, see Introducing the Amazon Linux 2023 runtime for AWS Lambda
Note
To run AL2023-based images locally, including with AWS Serverless Application Model (AWS SAM), you must use Docker version 20.10.10 or later.
Using an AWS base image for Java
To complete the steps in this section, you must have the following:
-
Java (for example, Amazon Corretto
) -
Docker
(minimum version 20.10.10 for Java 21 and later base images)
-
Start the Docker image with the docker run command. In this example,
docker-image
is the image name andtest
is the tag.docker run --platform linux/amd64 -p 9000:8080
docker-image
:test
This command runs the image as a container and creates a local endpoint at
localhost:9000/2015-03-31/functions/function/invocations
.Note
If you built the Docker image for the ARM64 instruction set architecture, be sure to use the
--platform linux/
option instead ofarm64
--platform linux/
.amd64
-
From a new terminal window, post an event to the local endpoint.
-
Get the container ID.
docker ps
-
Use the docker kill
command to stop the container. In this command, replace 3766c4ab331c
with the container ID from the previous step.docker kill
3766c4ab331c
To upload the image to Amazon ECR and create the Lambda function
-
Run the get-login-password
command to authenticate the Docker CLI to your Amazon ECR registry. -
Set the
--region
value to the AWS Region where you want to create the Amazon ECR repository. -
Replace
111122223333
with your AWS account ID.
aws ecr get-login-password --region
us-east-1
| docker login --username AWS --password-stdin111122223333
.dkr.ecr.us-east-1
.amazonaws.com -
-
Create a repository in Amazon ECR using the create-repository
command. aws ecr create-repository --repository-name
hello-world
--regionus-east-1
--image-scanning-configuration scanOnPush=true --image-tag-mutability MUTABLENote
The Amazon ECR repository must be in the same AWS Region as the Lambda function.
If successful, you see a response like this:
{ "repository": { "repositoryArn": "arn:aws:ecr:us-east-1:111122223333:repository/hello-world", "registryId": "111122223333", "repositoryName": "hello-world", "repositoryUri": "111122223333.dkr.ecr.us-east-1.amazonaws.com/hello-world", "createdAt": "2023-03-09T10:39:01+00:00", "imageTagMutability": "MUTABLE", "imageScanningConfiguration": { "scanOnPush": true }, "encryptionConfiguration": { "encryptionType": "AES256" } } }
-
Copy the
repositoryUri
from the output in the previous step. -
Run the docker tag
command to tag your local image into your Amazon ECR repository as the latest version. In this command: -
docker-image:test
is the name and tagof your Docker image. This is the image name and tag that you specified in the docker build
command. -
Replace
<ECRrepositoryUri>
with therepositoryUri
that you copied. Make sure to include:latest
at the end of the URI.
docker tag docker-image:test
<ECRrepositoryUri>
:latestExample:
docker tag
docker-image
:test
111122223333
.dkr.ecr.us-east-1
.amazonaws.com/hello-world
:latest -
-
Run the docker push
command to deploy your local image to the Amazon ECR repository. Make sure to include :latest
at the end of the repository URI.docker push
111122223333
.dkr.ecr.us-east-1
.amazonaws.com/hello-world
:latest -
Create an execution role for the function, if you don't already have one. You need the Amazon Resource Name (ARN) of the role in the next step.
-
Create the Lambda function. For
ImageUri
, specify the repository URI from earlier. Make sure to include:latest
at the end of the URI.aws lambda create-function \ --function-name
hello-world
\ --package-type Image \ --code ImageUri=111122223333
.dkr.ecr.us-east-1
.amazonaws.com/hello-world
:latest \ --rolearn:aws:iam::111122223333:role/lambda-ex
Note
You can create a function using an image in a different AWS account, as long as the image is in the same Region as the Lambda function. For more information, see Amazon ECR cross-account permissions.
-
Invoke the function.
aws lambda invoke --function-name
hello-world
response.jsonYou should see a response like this:
{ "ExecutedVersion": "$LATEST", "StatusCode": 200 }
-
To see the output of the function, check the
response.json
file.
To update the function code, you must build the image again, upload the new image to the Amazon ECR repository, and then use the update-function-code
Lambda resolves the image tag to a specific image digest. This means that if you point the image tag that was used to deploy the function to a new image in Amazon ECR, Lambda doesn't automatically update the function to use the new image.
To deploy the new image to the same Lambda function, you must use the update-function-code--publish
option creates a new version of the function using the updated container image.
aws lambda update-function-code \ --function-name
hello-world
\ --image-uri111122223333.dkr.ecr.us-east-1.amazonaws.com/hello-world:latest
\ --publish
Using an alternative base image with the runtime interface client
If you use an OS-only base image or an alternative base image, you must include the runtime interface client in your image. The runtime interface client extends the Using the Lambda runtime API for custom runtimes, which manages the interaction between Lambda and your function code.
Install the runtime interface client for Java in your Dockerfile, or as a dependency in your project. For example, to install the runtime interface client using the Maven package manager, add the following to your pom.xml
file:
<dependency> <groupId>com.amazonaws</groupId> <artifactId>aws-lambda-java-runtime-interface-client</artifactId> <version>2.3.2</version> </dependency>
For package details, see AWS Lambda Java Runtime Interface Client
The following example demonstrates how to build a container image for Java using an Amazon Corretto image
To complete the steps in this section, you must have the following:
-
Java (for example, Amazon Corretto
)
-
Create a Maven project. The following parameters are required:
-
groupId – The full package namespace of your application.
-
artifactId – Your project name. This becomes the name of the directory for your project.
-
-
Open the project directory.
cd
myapp
-
Open the
pom.xml
file and replace the contents with the following. This file includes the aws-lambda-java-runtime-interface-clientas a dependency. Alternatively, you can install the runtime interface client in the Dockerfile. However, the simplest approach is to include the library as a dependency. <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/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>example</groupId> <artifactId>hello-lambda</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> <name>hello-lambda</name> <url>http://maven.apache.org</url> <properties> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> </properties> <dependencies> <dependency> <groupId>com.amazonaws</groupId> <artifactId>
aws-lambda-java-runtime-interface-client
</artifactId> <version>2.3.2
</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-dependency-plugin</artifactId> <version>3.1.2</version> <executions> <execution> <id>copy-dependencies</id> <phase>package</phase> <goals> <goal>copy-dependencies</goal> </goals> </execution> </executions> </plugin> </plugins> </build> </project> -
Open the
directory, and find themyapp
/src/main/java/com/example/myapp
App.java
file. This is the code for the Lambda function. Replace the code with the following.Example function handler
package example; public class App { public static String sayHello() { return "Hello world!"; } }
-
The
mvn -B archetype:generate
command from step 1 also generated a dummy test case in thesrc/test
directory. For the purposes of this tutorial, skip over running tests by deleting this entire generated/test
directory. -
Navigate back to the project's root directory, and then create a new Dockerfile. The following example Dockerfile uses an Amazon Corretto image
. Amazon Corretto is a no-cost, multiplatform, production-ready distribution of the OpenJDK. -
Set the
FROM
property to the URI of the base image. -
Set the
ENTRYPOINT
to the module that you want the Docker container to run when it starts. In this case, the module is the runtime interface client. -
Set the
CMD
argument to the Lambda function handler.
Note that the example Dockerfile does not include a USER instruction
. When you deploy a container image to Lambda, Lambda automatically defines a default Linux user with least-privileged permissions. This is different from standard Docker behavior which defaults to the root
user when noUSER
instruction is provided.Example Dockerfile
FROM
public.ecr.aws/amazoncorretto/amazoncorretto:21
as base # Configure the build environment FROM base as build RUN yum install -y maven WORKDIR /src # Cache and copy dependencies ADD pom.xml . RUN mvn dependency:go-offline dependency:copy-dependencies # Compile the function ADD . . RUN mvn package # Copy the function artifact and dependencies onto a clean base FROM base WORKDIR /function COPY --from=build /src/target/dependency/*.jar ./ COPY --from=build /src/target/*.jar ./ # Set runtime interface client as default command for the container runtime ENTRYPOINT [ "/usr/bin/java", "-cp", "./*", "com.amazonaws.services.lambda.runtime.api.client.AWSLambda
" ] # Pass the name of the function handler as an argument to the runtime CMD [ "example.App::sayHello
" ] -
-
Build the Docker image with the docker build
command. The following example names the image docker-image
and gives it thetest
tag. docker build --platform linux/amd64 -t
docker-image
:test
.Note
The command specifies the
--platform linux/amd64
option to ensure that your container is compatible with the Lambda execution environment regardless of the architecture of your build machine. If you intend to create a Lambda function using the ARM64 instruction set architecture, be sure to change the command to use the--platform linux/arm64
option instead.
Use the runtime interface emulator
To install and run the runtime interface emulator on your local machine
-
From your project directory, run the following command to download the runtime interface emulator (x86-64 architecture) from GitHub and install it on your local machine.
-
Start the Docker image with the docker run command. Note the following:
-
docker-image
is the image name andtest
is the tag. -
/usr/bin/java -cp './*' com.amazonaws.services.lambda.runtime.api.client.AWSLambda example.App::sayHello
is theENTRYPOINT
followed by theCMD
from your Dockerfile.
This command runs the image as a container and creates a local endpoint at
localhost:9000/2015-03-31/functions/function/invocations
.Note
If you built the Docker image for the ARM64 instruction set architecture, be sure to use the
--platform linux/
option instead ofarm64
--platform linux/
.amd64
-
-
Post an event to the local endpoint.
-
Get the container ID.
docker ps
-
Use the docker kill
command to stop the container. In this command, replace 3766c4ab331c
with the container ID from the previous step.docker kill
3766c4ab331c
To upload the image to Amazon ECR and create the Lambda function
-
Run the get-login-password
command to authenticate the Docker CLI to your Amazon ECR registry. -
Set the
--region
value to the AWS Region where you want to create the Amazon ECR repository. -
Replace
111122223333
with your AWS account ID.
aws ecr get-login-password --region
us-east-1
| docker login --username AWS --password-stdin111122223333
.dkr.ecr.us-east-1
.amazonaws.com -
-
Create a repository in Amazon ECR using the create-repository
command. aws ecr create-repository --repository-name
hello-world
--regionus-east-1
--image-scanning-configuration scanOnPush=true --image-tag-mutability MUTABLENote
The Amazon ECR repository must be in the same AWS Region as the Lambda function.
If successful, you see a response like this:
{ "repository": { "repositoryArn": "arn:aws:ecr:us-east-1:111122223333:repository/hello-world", "registryId": "111122223333", "repositoryName": "hello-world", "repositoryUri": "111122223333.dkr.ecr.us-east-1.amazonaws.com/hello-world", "createdAt": "2023-03-09T10:39:01+00:00", "imageTagMutability": "MUTABLE", "imageScanningConfiguration": { "scanOnPush": true }, "encryptionConfiguration": { "encryptionType": "AES256" } } }
-
Copy the
repositoryUri
from the output in the previous step. -
Run the docker tag
command to tag your local image into your Amazon ECR repository as the latest version. In this command: -
docker-image:test
is the name and tagof your Docker image. This is the image name and tag that you specified in the docker build
command. -
Replace
<ECRrepositoryUri>
with therepositoryUri
that you copied. Make sure to include:latest
at the end of the URI.
docker tag docker-image:test
<ECRrepositoryUri>
:latestExample:
docker tag
docker-image
:test
111122223333
.dkr.ecr.us-east-1
.amazonaws.com/hello-world
:latest -
-
Run the docker push
command to deploy your local image to the Amazon ECR repository. Make sure to include :latest
at the end of the repository URI.docker push
111122223333
.dkr.ecr.us-east-1
.amazonaws.com/hello-world
:latest -
Create an execution role for the function, if you don't already have one. You need the Amazon Resource Name (ARN) of the role in the next step.
-
Create the Lambda function. For
ImageUri
, specify the repository URI from earlier. Make sure to include:latest
at the end of the URI.aws lambda create-function \ --function-name
hello-world
\ --package-type Image \ --code ImageUri=111122223333
.dkr.ecr.us-east-1
.amazonaws.com/hello-world
:latest \ --rolearn:aws:iam::111122223333:role/lambda-ex
Note
You can create a function using an image in a different AWS account, as long as the image is in the same Region as the Lambda function. For more information, see Amazon ECR cross-account permissions.
-
Invoke the function.
aws lambda invoke --function-name
hello-world
response.jsonYou should see a response like this:
{ "ExecutedVersion": "$LATEST", "StatusCode": 200 }
-
To see the output of the function, check the
response.json
file.
To update the function code, you must build the image again, upload the new image to the Amazon ECR repository, and then use the update-function-code
Lambda resolves the image tag to a specific image digest. This means that if you point the image tag that was used to deploy the function to a new image in Amazon ECR, Lambda doesn't automatically update the function to use the new image.
To deploy the new image to the same Lambda function, you must use the update-function-code--publish
option creates a new version of the function using the updated container image.
aws lambda update-function-code \ --function-name
hello-world
\ --image-uri111122223333.dkr.ecr.us-east-1.amazonaws.com/hello-world:latest
\ --publish