feature_support_multi-endpoints

[liucimin]

Description of the changes

New feature

Please describe:

• changes made in the Pull request

support etcd multi-endpoints

• type of testing done (both manual and automated)

both manual and automated

TODO

• [ ] Tests 1、change the .contiv.yaml to set the etcd cluster as "http://127.0.0.1:2381,http://127.0.0.2:2381,http://127.0.0.3:2381"

2、kubectl apply -f contiv.yaml

3、then the netplugin can use the multi-endpoint to init it's etcd client

• [ ] Documentation None