Function worker service is not done initializing. Please try again in a little while. Reason: HTTP 503 Service Unavailable

After I deployed the cluster on two centos7 servers, I was prompted with this error when I used pulsar-admin to create functions or use functions list commands. This problem did not occur when I used single node deployment. I have read other issues and found similar problems, but could not find a solution

pulsar version：2.6.0

Start by reproducing the HTTP 503 with pulsar-admin functions list and function creation on a two-server CentOS 7 cluster running Pulsar 2.6.0, then compare it with the reported single-node deployment. Done means the Function worker finishes initializing and both commands work without the service-unavailable error.

Written by the indexing model from the issue text.