didlich/nexus3 repository overview

⁠Introduction

This docker image is more or less a clone of sonatype's sonatype/nexus3⁠ image from the officiall docker hub repository. It differs in:

• base image is alpine 3.8
• JVM is oracle anapsix/alpine-java⁠
• JVM is docker aware⁠, -XX:+UseCGroupMemoryLimitForHeap, -XX:+UnlockExperimentalVMOptions
• set USER_UID + USER_GID for volume permissions

In this way the created image is very small compared to original. You can set USER_UID + USER_GID, which allows you to persist data in a host directoy without hadache.

⁠Run

    cd $HOME
    mkdir nexus-data

    docker run -d \
        -e USER_GID=$(id -g) \
        -e USER_UID=$(id -u) \
        -p 18081:8081 \
        -v $PWD/nexus-data:/nexus-data \
        --name nexus3 didlich/nexus3

⁠Build

docker build --rm=true --tag=didlich/nexus3 .

The following optional variables can be used when building the image:

• NEXUS_VERSION: Version of the Nexus Repository Manager
• NEXUS_DOWNLOAD_URL: Download URL for Nexus Repository, alternative to using
• NEXUS_VERSION to download from Sonatype
• NEXUS_DOWNLOAD_SHA256_HASH: Sha256 checksum for the downloaded Nexus Repository Manager archive. Required if NEXUS_VERSION or NEXUS_DOWNLOAD_URL is provided

⁠Test

curl -u admin:admin123 http://localhost:18081/service/metrics/ping

⁠Notes

• Default credentials are: admin / admin123
• It can take some time (2-3 minutes) for the service to launch in a new container. You can tail the log to determine once Nexus is ready:

docker logs -f nexus3

• Installation of Nexus is to /opt/sonatype/nexus.
• A persistent directory, /nexus-data, is used for configuration, logs, and storage. This directory needs to be writable by the Nexus process, which runs as USER_UID.
• There is an environment variable that is being used to pass JVM arguments to the startup script
  • INSTALL4J_ADD_VM_PARAMS, passed to the Install4J startup script. Defaults to
  • Xms1200m -Xmx1200m -XX:MaxDirectMemorySize=2g -Djava.util.prefs.userRoot=${NEXUS_DATA}/javaprefs.

This can be adjusted at runtime:

docker run -d \
    -p 8081:8081 \
    -e INSTALL4J_ADD_VM_PARAMS="-Xms2g -Xmx2g -XX:MaxDirectMemorySize=3g -Djava.util.prefs.userRoot=/some-other-dir" \
    --name nexus didlich/nexus3

Of particular note, -Djava.util.prefs.userRoot=/some-other-dir can be set to a persistent path, which will maintain the installed Nexus Repository License if the container is restarted.

• Another environment variable can be used to control the Nexus Context Path
  • NEXUS_CONTEXT, defaults to /

This can be supplied at runtime:

docker run -d \
    -p 8081:8081 \
    -e NEXUS_CONTEXT=nexus \
    --name nexus didlich/nexus3

⁠Persistent Data

There are two general approaches to handling persistent storage requirements with Docker. See Managing Data in Containers⁠ for additional information.

1. Use a docker volume. Since docker volumes are persistent, a volume can be created specifically for this purpose. This is the recommended approach.

docker volume create --name nexus-data

docker run -d \
    -p 8081:8081 \
    -v nexus-data:/nexus-data \
    --name nexus  didlich/nexus3

1. Mount a host directory as the volume. For this it is required to set USER_GID and USER_UID.

docker run -d \
    -p 8081:8081 \
    -e USER_GID=$(id -g) \
    -e USER_UID=$(id -u) \
    -v /some/dir/nexus-data:/nexus-data \
    --name nexus didlich/nexus3