Docker Build No Cache: Complete Guide to Clean Builds

To force Docker to perform a completely clean build without using the cache, you can use the --no-cache flag. Simply add this flag to your existing command:

docker build --no-cache -t u12_core -f u12_core .

This will force Docker to rebuild every layer from scratch, ignoring any cached layers, which should resolve your issue with aerospike not being properly installed despite the cache indicating it was.

Contents

• Using the --no-cache Flag
• Understanding Docker’s Build Cache
• Alternative Methods for Clean Builds
• Troubleshooting Cache-Related Issues
• Best Practices for Docker Builds

Using the --no-cache Flag

The most straightforward way to force a clean build is by using the --no-cache flag with your docker build command:

docker build --no-cache -t u12_core -f u12_core .

This flag tells Docker to ignore the cache completely and rebuild every layer from scratch. When you use this flag, you’ll see no “Using cache” messages in the build output - every step will be executed as if it’s the first time building.

Important considerations:

• Build time: Clean builds take significantly longer as Docker must execute every command in your Dockerfile
• Network usage: Each RUN command that downloads packages (like apt-get update) will re-download everything
• Storage: Build context and intermediate images will use more temporary storage

Here’s how the output would differ with --no-cache:

Step 1/18 : FROM ubuntu:12.04
 ---> eb965dfb09d2
Step 2/18 : MAINTAINER Pavan Gupta <pavan.gupta@gmail.com>
 ---> Running in a5f8c3d2e1f4
 ---> 4354ccf9dcd8
Step 3/18 : RUN apt-get update
 ---> Running in b7c9d4e5f6g7
 ---> bcbca2fcf204

Notice that instead of “Using cache”, you’ll see “Running in [container-id]” messages for each step that uses the cache.

Understanding Docker’s Build Cache

Docker uses a build cache to speed up builds by storing intermediate results. Understanding how this works helps you understand why your aerospike issue might be occurring and how to properly resolve it.

How Docker Cache Works

Docker builds images layer by layer. For each step in your Dockerfile, Docker checks if it can use a cached layer instead of rebuilding:

1. Cache lookup: Docker looks for a matching layer in the cache
2. Checksum calculation: Docker calculates a checksum for the build context and Dockerfile
3. Cache hit: If the checksum matches, Docker uses the cached layer
4. Cache miss: If anything differs, Docker rebuilds that layer

Why Your Aerospike Issue Might Be Happening

The problem you’re describing - where the cache indicates aerospike is installed but it’s not actually available in containers - typically occurs when:

• Partial build: A previous build failed midway through, leaving you with a partial installation
• Cache inconsistency: The cache is corrupted or inconsistent
• Build context changes: Something in your build context changed without updating the Dockerfile

Alternative Methods for Clean Builds

While --no-cache is the most direct approach, there are other methods to achieve clean builds in different scenarios.

Method 1: Modify the Dockerfile

Sometimes you can trigger a clean build by making a small, insignificant change to your Dockerfile:

# Add a comment or change a comment
# This forces Docker to rebuild from this point
RUN echo "Build timestamp: $(date)" > /dev/null && \
    apt-get update && \
    apt-get install -y openjdk-7-jdk

Method 2: Clean the Cache Manually

You can clean the Docker build cache entirely:

# Clean up all unused objects including build cache
docker system prune -a

# Or specifically clean build cache
docker builder prune -a

Warning: This removes all unused objects and will significantly increase build times afterward.

Method 3: Multi-stage Builds

For complex builds, consider using multi-stage builds to avoid caching issues between different build phases:

# Build stage
FROM ubuntu:12.04 as builder
RUN apt-get update && apt-get install -y build-essential
COPY . /app
RUN cd /app && make build

# Final stage  
FROM ubuntu:12.04
COPY --from=builder /app/dist /app/dist
# ... rest of your configuration

Troubleshooting Cache-Related Issues

Specific Fix for Your Aerospike Problem

Since you’re experiencing issues with aerospike not being properly installed despite the cache indicating it was, here’s a systematic approach:

1. Force a clean build with --no-cache
2. Check the build log carefully for any error messages during the aerospike installation steps
3. Verify the installation within the build container:

# Build with --no-cache
docker build --no-cache -t u12_core_fixed -f u12_core .

# Run a container and check if aerospike is actually installed
docker run -it --rm u12_core_fixed bash -c "which aerospike-server && dpkg -l | grep aerospike"

4. Inspect the final image to ensure all files are present:

docker run --rm -v /var/run/docker.sock:/var/run/docker.sock alpine docker run --rm -v $(pwd):/target u12_core bash -c "ls -la /opt/aerospike* 2>/dev/null || echo 'Aerospike not found'"

Common Cache Issues and Solutions

Best Practices for Docker Builds

When to Use --no-cache

Use --no-cache when:

• You’re debugging build issues
• You suspect cache corruption
• You’ve made significant changes to the Dockerfile or build context
• You need to ensure a completely fresh build

Optimizing Builds While Maintaining Reliability

To avoid unnecessary clean builds while maintaining reliability:

1. Use specific package versions in your Dockerfile:

   dockerfile

   RUN apt-get install -y aerospike-server-community=3.12.1
   

2. Add build verification steps:

   dockerfile

   RUN dpkg -l | grep aerospike || (echo "Aerospike installation failed" && exit 1)
   

3. Use build arguments for version control:

   dockerfile

   ARG AEROSPIKE_VERSION=3.12.1
   RUN apt-get install -y aerospike-server-community=${AEROSPIKE_VERSION}
   

4. Clean up apt cache in the same layer:

   dockerfile

   RUN apt-get update && apt-get install -y \
       openjdk-7-jdk \
       aerospike-server-community && \
       rm -rf /var/lib/apt/lists/*
   

Monitoring Build Health

Add verification commands to ensure your builds are working correctly:

# Add this to verify aerospike installation
RUN aerospike-server --help >/dev/null 2>&1 || \
    (echo "Aerospike server not properly installed" && exit 1)

This will cause the build to fail if aerospike isn’t properly installed, preventing you from creating broken images.

Conclusion

To force Docker to perform a clean build without using the cache, simply add the --no-cache flag to your build command: docker build --no-cache -t u12_core -f u12_core .. This will rebuild every layer from scratch and resolve your aerospike installation issue.

Key takeaways:

• Use --no-cache for debugging and when you suspect cache corruption
• Understand how Docker’s layer caching works to better troubleshoot build issues
• Consider alternative methods like modifying your Dockerfile or cleaning the cache manually
• Add verification steps in your Dockerfile to catch installation failures early
• For complex builds, use multi-stage builds and specific package versions to maintain reliability

The most immediate solution for your specific problem is to run the build with --no-cache and carefully inspect the output to ensure the aerospike installation completes successfully this time.

Sources

1. Docker Build Reference - --no-cache flag
2. Docker Build Cache Documentation
3. Docker Best Practices - Managing Build Cache