Replace AdminZkClient with AdminClient

[Lincong]

Motivations:

1. AdminZkClient gets information from Zookeeper which will be removed from Kafka as a dependency (KIP-500).

2. Java doc of AdminZkClient class says This is an internal class and no compatibility guarantees are provided, see org.apache.kafka.clients.admin.AdminClient for publicly supported APIs.

[ghost]

@Lincong can I take this one on? Or did you mean to assign it to yourself?

[Lincong]

@Lincong can I take this one on? Or did you mean to assign it to yourself?

Hi Jacob, I am glad that you want to take on this issue, and of course, you can. Just want to share some of my opinions regarding the implementation to resolve this issue.

1. In the codebase, find all places where AdminZkClient is used and replace them all since the goal is to completely migrate to AdminClient.

2. Note that there is an API-level semantics difference in AdminZkClient vs AdminClient regarding topic config changes. In AdminClient, the topic config change is incremental (diff-based) whereas AdminZkClient overrides topic config.

Let me know if you have any questions or have any things you want to discuss with me while you are implementing it. Thanks!

[ghost]

Will do. Thank you for the info.

[tomncooper]

@JacobHell Did you manage to complete this work?

[ghost]

@tomncooper no, it can be reassigned. Apologies.

[tomncooper]

I would be happy to give this issue a try, if no one else is working on it currently?

[efeg]

Thanks for working on this @tomncooper -- I reassigned the issue to you.

[efeg]

@tomncooper After #1644 is merged, the only key remaining item will be the use of AdminZkClient for replication throttle. Can I assume that you will be working on that part?

[tomncooper]

Hi @efeg, yes I will take that on.

[tmcgrath]

Question to confirm my understanding of this work. Once complete, this will remove the need to configure ZK access. If so, great!

[erikgb]

This issue seems to be fixed, ref. https://github.com/linkedin/cruise-control/wiki/Run-without-ZooKeeper. Close issue?