$ curl -O http://packages.confluent.io/archive/5.1/confluent-5.1.0-2.11.tar.gz
$ tar xzvf confluent-5.1.0-2.11.tar.gz
$ confluent-5.1.0/bin/confluent start
/confluent-5.1.0/etc/confluent-control-center/control-center.properties
:confluent.controlcenter.rest.listeners = http://<instance-external-ip>:9021
But can't connect to web UI by http://<instance-external-ip>:9021
Can some one help me? really appreciate!
Since you're accessing Confluent Control Center from another machine than the one on which it's hosted, you need to make sure that the firewall it open to allow traffic on the port (default 9021).