Persistent workflows to databases - Container Service for Kubernetes

Workflow-relevant resources in workflow clusters are periodically deleted. To analyze and trace the history of workflows, you can configure a persistence policy to persist workloads to a database. This way, you can view workflow logs even after the workflows or the pods of the workflows are deleted. This topic uses ApsaraDB RDS for MySQL as an example to describe how to configure a persitence policy to persistent workflows to a database.

Configure and use ApsaraDB RDS for MySQL

Create an ApsaraDB RDS for MySQL instance. For more information, see Create an ApsaraDB RDS for MySQL instance.
Important
Make sure that the virtual private cloud (VPC) of the ApsaraDB RDS for MySQL instance is the same as that of your workflow cluster. Add the VPC CIDR block to the whitelist of the ApsaraDB RDS for MySQL instance.
Create a database and an account for the ApsaraDB RDS for MySQL instance. For more information, see Create accounts and databases.
Run the following command to create a Secret named argo-mysql-config in the workflow cluster to store the username and password of the database.
```
kubectl create secret generic
```
Content of the Secret:
Note
Specify the username and password of the database that you created in the previous step.
```
apiVersion: v1
stringData:
  username: database-username
  password: database-password
kind: Secret
metadata:
  name: argo-mysql-config
  namespace: default
type: Opaque
```
Add persistence settings to the workflow-controller-configmap ConfigMap.
Note
- The workflow-controller-configmap ConfigMap is stored in the namespace that uses the cluster ID as its name.
- host indicates the address of the ApsaraDB RDS for MySQL instance.
- database indicates the name of the database.
- Set archive to true.
- archiveTTL indicates the retention period of the workflows. In this example, the parameter is set to 30d, which means that workflows are persisted for 30 days in the database. The valid values of the parameter are not limited.
```
  persistence: |
    connectionPool:
      maxIdleConns: 100
      maxOpenConns: 0
      connMaxLifetime: 0s # 0 means connections don't have a max lifetime
    archiveTTL: 30d
    archive: true
    mysql:
      host: rm-xxx.mysql.cn-beijing.rds.aliyuncs.com
      port: 3306
      database: argo-workflow
      tableName: argo_workflows
      userNameSecret:
        name: argo-mysql-config
        key: username
      passwordSecret:
        name: argo-mysql-config
        key: password
```

References

After workflows are persisted to the database, you can use the Argo CLI to view workflow logs even after the workflows are deleted. For more information, see Configure Log Service.