[Feature Request] Support Manage Multi RocketMQ cluster

[drivebyer]

Please describe the feature you are requesting.

I propose the enhancement of the current operator to support the management of multiple RocketMQ clusters by a single operator.

Provide any additional detail on your proposed use case for this feature.

rocketmq-operator/pkg/share/share.go

Lines 23 to 38 in ad72466

	GroupNum = 0
	// NameServersStr is the name server list
	NameServersStr = ""
	// IsNameServersStrUpdated is whether the name server list is updated
	IsNameServersStrUpdated = false
	// IsNameServersStrInitialized is whether the name server list is initialized
	IsNameServersStrInitialized = false
	// BrokerClusterName is the broker cluster name
	BrokerClusterName = ""
	// svc of controller for brokers
	ControllerAccessPoint = ""

Given the code above, our operator can only manage one RocketMQ cluster at a time (one nameservice deployment and one broker cluster). In a multi-tenant Kubernetes usage scenario, users may want to deploy multiple RocketMQ clusters in different namespaces.

Are you currently using any workarounds to address this issue?

One potential workaround might be to deploy one operator with one RocketMQ cluster in a single namespace. However, this is not a very efficient strategy in a Kubernetes environment.

If there are some sub-tasks using -[] for each subtask and create a corresponding issue to map to the sub task:

• sub-task1: Refactor the code to eliminate shared variables in https://github.com/apache/rocketmq-operator/blob/master/pkg/share/share.go
• sub-task2: Implement support for multiple RocketMQ clusters.
• sub-task3: Add a RocketMQ API to manage all resources (this is not a high priority at the moment).

[drivebyer]

@caigy PTAL

[caigy]

Good proposal. Some tips:

• the name of RocketMQ cluster should be added in CRDs and the relationship between RocketMQ clusters and CRs need to be maintained;
• After v4.9.4(included), the brokers and controllers can lookup the IPs from domain name of the name server.