Maven not in the Docker image

Oct 13, 2025 by magicalceylontours.com 66 views

Introduction

As a Java developer, building a Docker image for your application is an essential step in containerization. However, you may encounter errors during the Docker build process, which can be frustrating and time-consuming to resolve. In this article, we will discuss two common Docker build errors: exit code: 127 - Maven command not found and ERROR: failed to solve: failed to compute cache key. We will provide a step-by-step guide on how to troubleshoot and resolve these errors, ensuring a smooth Docker build process.

Error 1: exit code: 127 - Maven Command Not Found

When you encounter the exit code: 127 error, it typically means that the Docker build process is unable to find the Maven command. This error can occur due to several reasons, including:

Maven not installed: Make sure that Maven is installed on your system and the Maven executable is in the system's PATH.
Maven not in the Docker image: If you are using a base image that does not include Maven, you need to install it manually.
Maven version mismatch: Ensure that the Maven version in your Docker image matches the version you are using on your system.

To resolve this error, follow these steps:

Step 1: Verify Maven Installation

First, verify that Maven is installed on your system by running the following command in your terminal:

mvn --version

If Maven is not installed, you can download it from the official Apache Maven website.

Step 2: Update the Dockerfile

If Maven is not included in the base image, you need to install it manually. Update your Dockerfile to include the following lines:

# Install Maven
RUN apt-get update && apt-get install -y maven

Step 3: Verify Maven Version

Ensure that the Maven version in your Docker image matches the version you are using on your system. You can do this by adding the following lines to your Dockerfile:

# Set Maven version
ENV MAVEN_VERSION 3.8.6
# Install Maven
RUN apt-get update && apt-get install -y maven=${MAVEN_VERSION}

Step 4: Update the Maven Command

Finally, update the Maven command in your Dockerfile to use the correct path:

# Build stage
FROM eclipse-temurin:21 AS build
WORKDIR /app
COPY pom.xml .
COPY src ./src
RUN mvn --version
RUN mvn clean package -Dmaven.test.skip=true

Error 2: ERROR: failed to solve: failed to compute cache key

The ERROR: failed to solve: failed to compute cache key error typically occurs when the Docker build process is unable to compute the cache key for the image. This error can occur due to several reasons, including:

Inconsistent dependencies: Ensure that the dependencies in your Dockerfile are consistent and do not change between builds.
Missing or incorrect dependencies: Verify that all dependencies are included in the Docker image and are correctly specified.
Cache key mismatch: Ensure that the cache key is correctly computed and does not change between builds.

To resolve this error, follow these steps:

Step 1: Verify Dependencies

First, verify that the dependencies in your Dockerfile are consistent and do not change between builds. You can do this by adding the following lines to your Dockerfile:

# Set dependencies
ENV DEPENDENCIES eclipse-temurin:21 maven:3.8.6

Step 2: Update the Dockerfile

Update your Dockerfile to include the following lines:

# Build stage
FROM ${DEPENDENCIES} AS build
WORKDIR /app
COPY pom.xml .
COPY src ./src
RUN mvn --version
RUN mvn clean package -Dmaven.test.skip=true

Step 3: Verify Cache Key

Ensure that the cache key is correctly computed and does not change between builds. You can do this by adding the following lines to your Dockerfile:

# Compute cache key
RUN echo "Cache key: ${DEPENDENCIES}"

Step 4: Update the Docker Compose File

Finally, update the Docker Compose file to include the following lines:

version: '3'
services:
  app:
    build: .
    environment:
      - DEPENDENCIES=eclipse-temurin:21 maven:3.8.6

Conclusion

In this article, we discussed two common Docker build errors: exit code: 127 - Maven command not found and ERROR: failed to solve: failed to compute cache key. We provided a step-by-step guide on how to troubleshoot and resolve these errors, ensuring a smooth Docker build process. By following these steps, you can resolve these errors and successfully build your Docker image.

Best Practices

To avoid these errors in the future, follow these best practices:

Verify Maven installation: Ensure that Maven is installed on your system and the Maven executable is in the system's PATH.
Update the Dockerfile: Update your Dockerfile to include the correct Maven version and dependencies.
Verify cache key: Ensure that the cache key is correctly computed and does not change between builds.
Update the Docker Compose file: Update the Docker Compose file to include the correct dependencies and environment variables.

Introduction

In our previous article, we discussed two common Docker build errors: exit code: 127 - Maven command not found and ERROR: failed to solve: failed to compute cache key. We provided a step-by-step guide on how to troubleshoot and resolve these errors, ensuring a smooth Docker build process. In this article, we will answer some frequently asked questions related to these errors.

Q&A

Q: What is the exit code: 127 error in Docker?

A: The exit code: 127 error in Docker typically means that the Docker build process is unable to find the Maven command. This error can occur due to several reasons, including Maven not being installed, Maven not being in the Docker image, or Maven version mismatch.

Q: How do I resolve the exit code: 127 error?

A: To resolve the exit code: 127 error, follow these steps:

Verify that Maven is installed on your system and the Maven executable is in the system's PATH.
Update your Dockerfile to include the correct Maven version and dependencies.
Verify that the Maven version in your Docker image matches the version you are using on your system.
Update the Maven command in your Dockerfile to use the correct path.

Q: What is the ERROR: failed to solve: failed to compute cache key error in Docker?

A: The ERROR: failed to solve: failed to compute cache key error in Docker typically occurs when the Docker build process is unable to compute the cache key for the image. This error can occur due to several reasons, including inconsistent dependencies, missing or incorrect dependencies, or cache key mismatch.

Q: How do I resolve the ERROR: failed to solve: failed to compute cache key error?

A: To resolve the ERROR: failed to solve: failed to compute cache key error, follow these steps:

Verify that the dependencies in your Dockerfile are consistent and do not change between builds.
Update your Dockerfile to include the correct dependencies and environment variables.
Verify that the cache key is correctly computed and does not change between builds.
Update the Docker Compose file to include the correct dependencies and environment variables.

Q: How do I troubleshoot Docker build errors?

A: To troubleshoot Docker build errors, follow these steps:

Check the Docker build logs for any error messages.
Verify that the Dockerfile is correctly formatted and includes the correct dependencies and environment variables.
Verify that the Docker Compose file is correctly formatted and includes the correct dependencies and environment variables.
Try building the Docker image again with the --no-cache flag to force a rebuild.

Q: How do I optimize Docker build performance?

A: To optimize Docker build performance, follow these steps:

Use a multi-stage build to reduce the size of the final Docker image.
Use a Docker cache to store intermediate build results and reduce rebuild time.
Use a Docker Compose file to define the build process and dependencies.
Use a CI/CD pipeline to automate the build process and reduce manual intervention.

Conclusion

In this article, we answered some frequently asked questions related to the exit code: 127 - Maven command not found and ERROR: failed to solve: failed to compute cache key errors in Docker. We provided a step-by-step guide on how to troubleshoot and resolve these errors, ensuring a smooth Docker build process. By following these steps, you can resolve these errors and successfully build your Docker image.

Best Practices

To avoid these errors in the future, follow these best practices:

Verify Maven installation: Ensure that Maven is installed on your system and the Maven executable is in the system's PATH.
Update the Dockerfile: Update your Dockerfile to include the correct Maven version and dependencies.
Verify cache key: Ensure that the cache key is correctly computed and does not change between builds.
Update the Docker Compose file: Update the Docker Compose file to include the correct dependencies and environment variables.
Troubleshoot Docker build errors: Check the Docker build logs for any error messages and verify that the Dockerfile and Docker Compose file are correctly formatted.
Optimize Docker build performance: Use a multi-stage build, Docker cache, and Docker Compose file to reduce rebuild time and manual intervention.