Tomcat Docker Images#

The cours-devops-docker repository uses the official tomcat Docker image as a key teaching example, specifically for TP07 (practical lab #7), where students deploy a WAR file into a running Tomcat container 1.

Current Tag Convention#

All actively used and automatically updated Tomcat tags follow the pattern:

tomcat:<version>-jdk<jdk_version>-temurin-noble

The tag in use as of the latest automated update is tomcat:11.0.25-jdk25-temurin-noble 2. This is the format targeted by the updatecli automation and reflects the upstream Tomcat project's current publishing strategy: Ubuntu Noble (Ubuntu 24.04 LTS) base with Eclipse Temurin JDK.

Alpine Images: No Longer Available#

Tomcat Alpine-based image variants (e.g., tomcat:X.Y-alpine) are no longer published on Docker Hub for current Tomcat versions. The official Tomcat Docker image maintainers dropped Alpine variants in favor of Ubuntu Noble (temurin-noble) as the primary base OS. This is consistent with the same trend observed for other official Docker images such as Maven, which also dropped Alpine variants in favor of Ubuntu Noble 3.

⚠️ The exam document still contains a reference to tomcat:10-jre17-temurin-alpine in a Dockerfile example 4. This tag may not exist on Docker Hub for recent versions and should be treated as illustrative only.

updatecli Automation#

The repository uses updatecli to automatically discover the latest Tomcat tag and open a GitHub pull request when a new version is released. The configuration lives in updatecli/updatecli.d/tomcat-updates.yaml.

How it works#

1. Source — Queries Docker Hub for the latest tomcat image tag matching the filter 5:

   • tagfilter: '^1\d+\.\d+\.\d+-jdk(2[5-9]|[3-9]\d+)-temurin-noble$'
   • versionfilter: same regex without the leading anchor ^1
   • This restricts updates to: Tomcat 11.x (major version starting with 1), JDK 25 or higher, Temurin JDK, Ubuntu Noble base.

2. Targets — Updates two locations inside content/chapitres/fichiers-nommage-inspect.adoc 6:

   • The inline comment explaining the docker run command.
   • The docker run command itself.

3. Action — Opens a GitHub pull request titled [TP07] Update Tomcat Docker image to <new_tag> with the dependencies label 7.

Tag filter rationale#

The regex ^1\d+\.\d+\.\d+-jdk(2[5-9]|[3-9]\d+)-temurin-noble$ was deliberately tightened from a looser initial pattern introduced in the initial PR to avoid picking up legacy Tomcat 8/9/10.x versions, pin to JDK 25+ only (preventing regressions to older JDK variants), and reduce noisy or invalid update proposals by restricting the candidate tag space 8.

Key Files#