zookeeper installation on multiple AWS EC2instances

I am new to zookeeper and aws EC2. I am trying to install zookeeper on 3 ec2 instances.

as per zookeeper document, I have installed zookeeper on all 3 instances, created zoo.conf and add below configuration:

tickTime=2000
initLimit=10
syncLimit=5
dataDir=/opt/zookeeper/data
clientPort=2181
server.1=localhost:2888:3888
server.2=<public ip of ec2 instance 2>:2889:3889
server.3=<public ip of ec2 instance 3>:2890:3890

also I have created myid file on all 3 instances as /opt/zookeeper/data/myid as per guideline..

I have couple of queries as below:

1. 
   

   whenever I am starting zookeeper server on each instance, it will start in standalone mode.(as per logs)

   
   


2. 
   

   can above configuration is really gonna connect to each other? port 2889:3889 & 2890:38900 - what these port all about. can I need to configure it on ec2 machine or I need to give some other port against it?

   
   


3. 
   

   Is I need to create security group to open these connection? I am not sure how to do it in ec2 instance.

   
   


4. 
   

   How to confirm all 3 zookeeper has started and they can communicate with each other?