Increase in alpine image size since liquibase:4.31.0-alpine

[ashleyheath]

It seems that with the release of the 4.31.0-alpine image the image size near-doubled (and is now pretty much the same size as the non-alpine image):

Is this a regression?

[jandroav]

Hello @ashleyheath thanks for reporting this.

I see that:

• Primary cause: Liquibase package size increased from 160MB (4.30.0) to 349MB (4.31.0), an increase of 189MB (liquibase-checks extension was added)
• Secondary cause: OpenJDK upgrade from 17 to 21 added about 16MB

Looking at both Dockerfiles, the size difference is now minimal because both images are using the same Java 21 JRE, which is the largest component. The current 26MB difference (434MB vs 408MB) is primarily from Alpine's smaller base image and package management overhead, but Java remains the dominant factor.

The reason Alpine shows a bigger storage increase with JRE upgrades is due to fundamental differences in how these base images handle Java.

Base Image Differences

Standard Ubuntu Image (Dockerfile):

• Uses eclipse-temurin:21-jre-jammy - comes with JRE 21 pre-installed and optimized
• The base image already includes a full JRE, so the image size is already "large"
• JRE upgrade impact is proportionally smaller relative to the total image size

Alpine Image (Dockerfile.alpine):

• Uses alpine:3.22 - minimal base image (~5MB)
• Installs openjdk21-jre-headless as an additional package
• Starts from a much smaller baseline, so any JRE addition appears proportionally larger

Why the Difference is More Pronounced

1. Proportional Impact: If Alpine goes from 50MB to 150MB (+100MB), that's a 200% increase. If Ubuntu goes from 200MB to 250MB (+50MB), that's only a 25% increase.

2. Package Management: Alpine's apk packages might include different dependencies or optimizations compared to the pre-built Eclipse Temurin images.

3. Compression Differences: The layering and compression in the pre-built Temurin image is likely more optimized than installing OpenJDK via package manager.

ping: @jnewton03

[ashleyheath]

Thanks for the investigation and detailed write-up @jandroav !

From the sounds of it, the smaller size of the older alpine image versions was more a fortunate side-effect rather than a deliberate packaging goal? Is there any appetite for publishing additional images without the liquibase-checks extension (if that's even possible)?

For context, we've been building a minimal image on top of the liquibase ones that simply contains our changelogs and a script to execute them. This gets downloaded and run at various points in our CI/CD pipelines so the smaller image size was beneficial in terms of download speed.

[akelsch]

See #358. I would be interested to know if something is in the works, at this point the issue is already half a year old.

The alpine image is not really "alpine-esque". In the grand scheme of things it does not make a substantial difference between using the alpine or ubuntu image because of the substantial size of liquibase itself.