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Nexus Repository Manager is the artifact hub for the CI/CD stack. It stores all build outputs — WAR files, JARs, and versioned configuration property tarballs. The Jenkins pipeline deploys artifacts to the maven-snapshots repository at the end of a successful pipeline run, immediately after the SonarQube Quality Gate passes. Every deployed artifact is versioned with a build number and timestamp, giving you a complete history of every build stored in one place.

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Quick Reference

PropertyValue
Port8081
Imagesonatype/nexus3
Container Namenexus
Default Credentialsadmin / [generated password]
Data Volumenexus_data

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Getting the Admin Password

Nexus generates a random admin password on first start and writes it to /nexus-data/admin.password inside the container. Retrieve it with:
docker exec nexus cat /nexus-data/admin.password
This file is automatically deleted after you complete the first-login setup wizard and change the password. If the file is already gone, the password was changed during a previous login — check your records or reset (see Troubleshooting).

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Default Repositories

Nexus ships with a default set of repositories. The pipeline uses two hosted Maven repositories:

maven-releases

Stores release-version artifacts (e.g., 1.0.0). Redeploy policy is typically set to Disable to prevent accidental overwrites of released artifacts.

maven-snapshots

Stores snapshot-version artifacts (e.g., 1.0.0-SNAPSHOT). Redeploy is allowed, which is required for the mvn deploy step to succeed on repeated pipeline runs.
If the repositories are not present after first startup, create them manually:
1
Log in to Nexus
2
Navigate to http://localhost:8081 and sign in with the admin credentials retrieved above.
3
Open Repository Administration
4
Click the gear icon (Server administration and configuration) in the top navigation bar.
5
Create Each Repository
6
Click Repositories → Create repository, then select maven2 (hosted).
7
  • For releases: set Name to maven-releases and Version policy to Release.
  • For snapshots: set Name to maven-snapshots, Version policy to Snapshot, and Deployment policy to Allow redeploy.

    • ​
    Pipeline Integration

    The Jenkinsfile Deploy to Nexus stage uses mvn deploy with an alternate deployment repository pointing to the maven-snapshots hosted repository. Credentials are injected from the nexus-credentials Jenkins credential configured by 03-configure-credentials.groovy. 
    stage('Deploy to Nexus') {
    when {
        anyOf {
            branch 'main'
            branch 'master'
            branch 'develop'
        }
    }
    steps {
        withCredentials([usernamePassword(
            credentialsId: 'nexus-credentials',
            usernameVariable: 'NEXUS_USER',
            passwordVariable: 'NEXUS_PASS'
        )]) {
            sh """
                mvn deploy -DskipTests \
                -DaltDeploymentRepository=nexus::default::${NEXUS_URL}/repository/maven-snapshots
            """
        }
    }
}
    The deploy stage only runs on main, master, or develop branches, preventing snapshot uploads from feature branches.

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    Properties Version Storage

    The enhanced Jenkinsfile (Jenkinsfile.enhanced) also uploads versioned environment configuration tarballs to Nexus via curl. This lets you retrieve the exact configuration properties that were active at the time of any build: 
    curl -v -u ${NEXUS_USER}:${NEXUS_PASS} \
    --upload-file properties-${ENVIRONMENT}-${APP_VERSION}.tar.gz \
    ${NEXUS_URL}/repository/maven-snapshots/properties/${JOB_NAME}/${APP_VERSION}/properties-${ENVIRONMENT}-${APP_VERSION}.tar.gz
    The version format is {BUILD_NUMBER}-{TIMESTAMP} (e.g., 42-20251025-143022), making it easy to correlate a deployed WAR with its corresponding properties bundle.

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    Maven settings.xml Configuration

    For mvn deploy to authenticate against Nexus, Maven must resolve the server credentials from settings.xml. The <server> block ID must match the <id> used in your pom.xml <distributionManagement> section. 
    <settings>
  <servers>
    <server>
      <id>nexus-snapshots</id>
      <username>admin</username>
      <password>${env.NEXUS_PASS}</password>
    </server>
    <server>
      <id>nexus-releases</id>
      <username>admin</username>
      <password>${env.NEXUS_PASS}</password>
    </server>
  </servers>
</settings>
    Use the Jenkins Config File Provider plugin to manage settings.xml centrally in Jenkins rather than baking it into each project. The pipeline can then inject it with withMaven(mavenSettingsConfig: 'nexus-settings').

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    Memory Tuning

    Nexus runs on a Java-based application server and requires adequate heap allocation. The default settings in docker-compose.yml are suitable for development: 
    nexus:
  environment:
    - INSTALL4J_ADD_VM_PARAMS=-Xms512m -Xmx512m -XX:MaxDirectMemorySize=273m
    For production workloads with many concurrent users or large repositories, significantly increase the heap. The override example shows recommended production values: 
    nexus:
  environment:
    - INSTALL4J_ADD_VM_PARAMS=-Xms2048m -Xmx2048m -XX:MaxDirectMemorySize=2048m
    Nexus performs best when -Xms and -Xmx are equal, preventing JVM heap resize operations under load. Always pair them at the same value in production.

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    Troubleshooting

    Nexus initialization can take 5–10 minutes on first boot, especially on machines with limited I/O throughput. Check current status:
    docker compose logs nexus | tail -50
docker stats nexus
    If memory is insufficient, reduce the heap temporarily while diagnosing:
    nexus:
  environment:
    - INSTALL4J_ADD_VM_PARAMS=-Xms256m -Xmx512m -XX:MaxDirectMemorySize=273m
    Restart after adjusting:
    docker compose restart nexus
    1. The file may not exist yet — Nexus may still be initializing. Wait 5–10 minutes, then retry: 
      docker exec nexus ls -la /nexus-data/admin.password
    2. If the file is truly missing, it was already deleted after a previous first-login. Check pipeline logs or team records for the password that was set.
    3. If no one has the password, the classic fallback is to try admin123 — this was the default for older Nexus versions and occasionally applies: 
      # Attempt login with the legacy default
curl -u admin:admin123 http://localhost:8081/service/rest/v1/status
    4. As a last resort, reset the entire Nexus volume (this loses all stored artifacts): 
      docker compose down -v
docker compose up -d
    1. Confirm the credentials stored in the nexus-credentials Jenkins credential match the actual Nexus admin password.
    2. Verify that the <server> <id> in settings.xml exactly matches the <id> in pom.xml <distributionManagement> — they are case-sensitive.
    3. Log in to the Nexus UI and confirm the maven-snapshots repository Deployment policy is set to Allow redeploy:
      • Navigate to Repositories → maven-snapshots → Edit.
      • Under Hosted, set Deployment policy to Allow redeploy.
    4. Verify that the Nexus user account has the nx-repository-write-* privilege or is assigned the nx-admin role.
    Nexus does not auto-create these repositories from the base image. If they are missing, create them manually via the UI:
    1. Log in to http://localhost:8081 with admin credentials.
    2. Click the gear icon → Repositories → Create repository.
    3. Select maven2 (hosted).
    4. Create maven-releases with Version policy: Release.
    5. Create maven-snapshots with Version policy: Snapshot and Deployment policy: Allow redeploy.
    Alternatively, automate repository creation using the Nexus REST API or a provisioning Groovy script placed in nexus/nexus-config.groovy.

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