Struggling With DolphinScheduler Setup? This FAQ Can Help | HackerNoon

Apache DolphinScheduler, as a scalable workflow scheduling system, is widely used for big data task orchestration. However, users may encounter issues such as environment setup, service startup, and workflow execution actual use. This article, combined with community documents and user practice experience, organizes the following frequently asked questions and detailed solutions to help users quickly locate and solve.

I. Installation and Deployment Issues

1. Environment Dependency Configuration Error
   • Issue: Deployment fails due to missing JDK Maven, or database configuration.
   • Solution:

     • Install JDK 1.8 and configure the JAVA_HOME environment variable.

     • Install 3.6 , set MAVEN_HOME and add it to the system PATH.

     • The database must support MySQL 5.7 or PostgreSQL8.2.15 , and the metadata database should be correctly initialized (e.g., execute CREATE DATABASE and user authorization).

2. PseudoCluster Deployment Failure
   • Issue: Services cannot start in pseudo-cluster mode due to SSH passwordless configuration or permission issues.
   • Solution: Ensure that the deployment user (such as dolphinscheduler) has sudo passwordless permissions and modify the /etc/sudoers file to comment Defaults requiretty.
     • Configure SSH passwordless login: after generating the key, use ssh-copy-id to distribute the public key to the cluster nodes3. ZooKeeper Dependency Conflict
   • Issue: After version upgrade, it depends on a specific version of ZooKeeper (such as CDH’sK3.4.5).
   • Solution:
     • Specify the parameter when recompiling DolphinScheduler, for example, mvn clean installPrelease -Dzk-3.4.

II. Service Startup and Configuration Issues

1. Service Startup Failure -Issue**: Port occupation, dependent services not started, or log errors.
   • Solution:
     • Check port occupation: use netstat -ano |str :12345 (default UI port).
     • View log files: such as logs/dolphin-scheduler-start.log, to locate the of the error.
     • Ensure that dependent services (such as the database, ZooKeeper) have been started.
2. Database Connection Failure
   • Issue: The service cannot connect due to incorrect metadata database configuration.
   • Solution:
     • Modify bin/env/dolphinscheduler_env.sh, confirm the URL, username, and password.
     • For MySQL 8 , manually download the mysql-connector-java driver (8.0.16 ) and it in the libs directory of each module.

III. Version Upgrade and Compatibility Issues

1. Cross-version Upgrade Failure

• Issue: Compatibility issues when upgrading directly from 1.3 to 3.x.
  • Solution:
    • Use a step-by-step: 1.3 → 2.0.x → 3.0.x→​3.2.x, refer to the official upgrade documentation and test data.

2. Python SDK Compatibility
   • Issue: Python gateway unable to execute workflows or version incompatibility.
   • Solution: – Upgrade the Python SDK to a version that supports the 3.2.x scheduler and adapt to the latest Java trigger code.
3. Python SDK Compatibility – Issue: What stable version is currently recommended for use in production environments?
   • Solution:
     • It is recommended to use version 31.9​.

IV. Resource Management and Service Operation

1. File Storage Configuration Issues
   • Issue: Tasks cannot read resource files when using Minio or S3 storage.
   • Solution:
     • Check if the resource reference path is correct and ensure that storage service (such as HDFS/S3/Minio) is configured in common.properties.
2. Service Crash and Data Compensation Failure

V. Community Resources and Advanced Support

• Official Documentation: Refer to the DolphinScheduler official website for deployment guides and parameter configurations.
• Support: Join the WeChat group or get real-time answers through the Weekly FAQ.
• Contribution Guide: Beginners can start with document fixes or simple code issues to participate in community contributions.

By the above solutions, users can systematically address common issues in DolphinScheduler. If the problem still cannot be resolved, it is recommended to further investigate by combining log analysis and support.