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On the Evolution of Technical Lag in
Debian-based DockerHub Images
Ahmed Zerouali, Tom Mens, Alexandre Decan,
Jesus Gonzalez-Barahona and Gregorio Robles.
THE 19TH BELGIUM-NETHERLANDS SOFTWARE EVOLUTION
WORKSHOP
LUXEMBOURG, 3/4 DECEMBER 2020
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About Docker container images
- A Docker image is a read-only template that contains a set of instructions for
creating a container.
- A container is a lightweight, standalone, executable package of software.
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Motivation
ClusterHQ, Inc
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Other main concerns for
container adoption:
• Dependencies (required
packages)
• Bugs in third-party software
• Outdated third-party software
Motivation
Anchore, Inc
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A method to assess how vulnerable,
buggy and outdated Docker images are.
Goal
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Technical lag
Technical lag: the increasing difference between deployed software
packages and the ideal available upstream packages.
➢ Ideal: stability, security, functionality, etc.
➢ Difference: version updates, bugs, vulnerabilities, line of
code, commits, etc.
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Technical Lag
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● is a set of component releases
● is a set of possible lag values
● ideal : → is a function returning the “ideal” component release
● delta : x → is a function computing the difference between
two component releases
● agg : is a function aggregating the results of a set of lags
A Framework of Technical Lag
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Given a technical lag framework , we define:
Aggregated Technical lag:
Technical lag:
Let be a set of components, then:
A Framework of Technical Lag
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How does technical lag evolve in DockerHub
images?
Research Question
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Technical Lag in DockerHub images
➢ Ideal: Highest available version
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Case study
Type of data Data source
Package metadata Debian Archive
Security vulnerabilities Debian Security Tracker
Bugs Ultimate Debian Database
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Results
/Package lag
Community images have higher package lag than official ones.
Only < 3% of packages are outdated in community images.
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Testing images have higher package lag, because they are
frequently updated in the Debian repository.
Results
/Package lag
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Results
/Time lag
The median time lag of community images is well over a year,
and it is highest for OldStable images.
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Results
/Version lag
The median version lag of community images is 7 missed
versions. Testing images have a higher version lag.
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Results
/Vulnerability lag
Community images have a median vulnerability lag of 10 vulnerabilities.
OldStable images have a higher vulnerability lag than other images.
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Results
/Bug lag
Testing images have a higher bug lag than Stable images
because they tend to come with bug fixes.
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Discussion
Package lag
Time lag
Version lag
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Vulnerability lag
Bug lag
Discussion
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Technical lag should be measured in different ways, offering
complementary information.
The technical lag could help Docker users to keep their images
and containers in a healthy shape.
Conclusion
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Technical Lag in DockerHub images
➔ package lag indicates whether a given package release is outdated;
➔ time lag quantifies the time difference between two release dates;
➔ version lag quantifies the number of missed versions between releases;
➔ vulnerability lag measures the difference in number of vulnerabilities;
➔ bug lag measures the difference in number of bugs.
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