如何在ruby中连接到EC2 Cassandra实例

Question

I am new to cassandra so I followed this guide on how to get Cassandra set up on an EC2 instance. I have gotten it all set up and ready to go but for some reason I'm not able to connect from ruby. Here is what I have been trying:

 require 'cassandra'
 client = Cassandra.new('PERSON', 'ec2-xx-xx-xxx-xxx.compute-1.amazonaws.com:9160')
   # =>
   #  <Cassandra:0x100cda3b0
   #    @auto_discover_nodes = true,
   #    @column_name_class = {},
   #    @column_name_maker = {},
   #    @is_super = {},
   #    @sub_column_name_class = {},
   #    @sub_column_name_maker = {},
   #    attr_accessor :keyspace = "PERSON",
   #    attr_reader :servers = [
   #      [0] "ec2-xx-xx-xxx-xxx.compute-1.amazonaws.com:9160"
   #    ],
   #    attr_reader :thrift_client_class = ThriftClient < AbstractThriftClient,
   #    attr_reader :thrift_client_options = {
   #      :transport_wrapper => Thrift::FramedTransport < Thrift::BaseTransport,
   #      :thrift_client_class => ThriftClient < AbstractThriftClient,
   #      :protocol => Thrift::BinaryProtocolAccelerated < Thrift::BinaryProtocol
   #    }
   #  >

Then when I tried to use the client, I get this error:

client.keyspaces
  #=> ThriftClient::NoServersAvailable: No live servers in [ec2-xx-xx-xxx-xxx.compute-1.amazonaws.com:9160].

I am able to connect via SSH so I'm not sure what I'm doing wrong here.

Update:

My security group includes:

port: 9160

protocol: tcp

source: sg-xxxxxxxx

Answer 1

Where is the "source" of the connection into the Cassandra server?

The security group you are using only opens up port 9160 to instances in the group sg-xxxxxxxx . If you are trying to connect from anywhere else (like the outside world) you will not be successful.

Answer 2

There are two things to check:

• do you have a firewall running on the client and/or the server?
• do you allow access in your EC2 security group from your client to your server?