Docker Image Optimization

[Mayank77maruti]

Short, Descriptive Title

Optimize Docker Build Process for Application

Summary

Implements performance and size optimizations for the application's Dockerfile, reducing image size and improving build efficiency.

Motivation

• Reduce Docker image size
• Improve build and deployment speed
• Enhance security of container image
• Optimize resource utilization

Goals

• Decrease final image size by 30-50%
• Improve build caching
• Maintain existing application functionality
• Reduce build and deployment time

Non-Goals

• Complete refactoring of application architecture
• Changing core application logic
• Introducing new dependencies

Proposal

Replace current Dockerfile with an optimized multi-stage build using Alpine base image and Go build optimizations.

Risks and Mitigations

• Risk: Potential compatibility issues
  • Mitigation: Comprehensive testing across different environments
• Risk: Performance impact
  • Mitigation: Benchmark and compare build times and image sizes

Design Details

1. Use Alpine-based Golang image
2. Implement multi-stage build
3. Add Go build optimization flags
4. Minimize layer size and count

Test Plan

Unit Tests

• Verify application starts correctly
• Check binary functionality remains unchanged
• Validate dependency resolution

Integration Tests

• Deploy to staging environment
• Run full application test suite
• Verify network and system interactions

Feature Enablement and Rollback

• Seamless rollout possible
• No default behavior changes
• Can revert to previous Dockerfile if issues occur

Monitoring Requirements

Events

• Event Reason: DockerBuildOptimization
• Log build process and optimization steps

Metrics to Add

• Build time
• Image size
• Layer cache hit/miss rates

Dependencies

• Go 1.21+
• Docker 18.09+

Drawbacks

• Slightly more complex Dockerfile
• Requires careful testing

Alternatives Considered

1. Using official Golang image without optimizations
2. Using more minimal base images
3. Manually optimizing without multi-stage build

Proposed Dockerfile Changes

# Optimized Dockerfile
FROM golang:1.21-alpine AS builder

WORKDIR /app

# Install build dependencies
RUN apk add --no-cache git

# Leverage build cache
COPY go.mod go.sum ./
RUN go mod download && go mod verify

# Copy source and build
COPY . .
RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build \
    -ldflags="-s -w" \
    -trimpath \
    -o /bin/manager \
    main.go

# Final lightweight image
FROM gcr.io/distroless/static:nonroot
COPY --from=builder /bin/manager /manager
USER 65532:65532
ENTRYPOINT ["/manager"]

Checklist

• Updated Dockerfile
• Tested build process
• Verified application functionality
• Updated documentation
• Performed size and performance comparison