In this article, we will use DolphinScheduler to create and run a simple workflow step by step. During this journey, you will learn the basic concepts of DolphinScheduler and know the most basic configuration to run the workflow.
Setup Dolphinscheduler
You have to install and start dolphinscheduler first before go ahead. For beginners, we recommend setting up DolphinScheduler with the official Docker image or with the standalone server.
- Standalone server
- Docker
Build Your First Workflow
You can log in DolphinScheduler through http://localhost:12345/dolphinscheduler/ui and the default username/password is admin/dolphinscheduler123.
Create Tenant
Tenant is an important concept while using DolphinScheduler, so let's briefly introduce the concept of tenant first.
DolphinScheduler maps the admin account you use to log into DolphinScheduler to user. To better control system resources, DolphinScheduler introduces the concept of tenants, which are used to execute tasks.
The brief is as follows:
- User: login web UI, do all operations in the web UI, including workflow management and tenant creation.
- Tenant: the actual executor of the task, A Linux user for DolphinScheduler worker.
We can create a tenant in DolphinScheduler Security -> Tenant Manage page.
NOTE: The user will bind to a default tenant when it is created, if you use the default tenant, the task will be executed by worker's bootstrap user.
Assign Tenant to User
As we have shown above in Create Tenant section, theuser can not run tasks until we assign it with a tenant.
We can assign a tenant to a specific user in DolphinScheduler Security -> User Manage page.
After we create a tenant and assign it to a user, we can start creating a simple workflow in DolphinScheduler.
Create Project
But in DolphinScheduler, all workflows must belong to a project, so we need to create a project first.
We can create a project in DolphinScheduler Project page by clicking Create Project button.
Create Workflow
Now we can create a workflow for the project tutorial. Click the project we just created, go to Workflow Definition page, click Create Workflow button, and we will redirect to the workflow detail page.
Create Tasks
We can use the mouse to drag the task you want to create from the toolbar in the workflow canvas. In this case, we create a Shell task. Entering the necessary information for the task, we just fill the attribute Node Name with Script to the task for this simple workflow. After that, we can click the Save button to save the task into the workflow. We create another task using the same way.
Set Task Dependency
So we have two different tasks with different names and commands to run in the workflow. The only thing missing from the current workflow is task dependency. We can add dependency using the mouse to drag the arrow from the upstream task to the downstream and then release the mouse. And you can see the link with the arrow between the two tasks is created, from the upstream task to the downstream one. Finally, we can click the Save button from the top right corner to save the workflow, do not forget to enter the name of the workflow.
Run Workflow
After all done, we can run the workflow by clicking the Online and then the Run button from the workflows list. If you want to see the workflow instance, just go to Workflow Instance page, you can see the workflow instance is running and the status is Executing.
View Log
If you want to view the task log, please click the workflow instance from the workflow instance list, then find the task you want to view the log, right-click the mouse and select View Log from the context dialog, and you can see the detailed log of the task.
You can see the task printing Hello DolphinScheduler and Ending... which is the same as we defined when creating the tasks.
You just finished the first tutorial of DolphinScheduler, you can now run some simple workflows in DolphinScheduler, congratulations!
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