Class: Cassandra::AddressResolution::Policies::EC2MultiRegion

Inherits:
Object
  • Object
show all
Defined in:
lib/cassandra/address_resolution/policies/ec2_multi_region.rb

Overview

Note:

Initializing this policy is not necessary, you should just pass :ec_multi_region to the :address_resolution option of Cassandra.cluster

This policy resolves private ips of the hosts in the same datacenter and public ips of hosts in other datacenters.

Instance Method Summary collapse

Instance Method Details

#resolve(address) ⇒ IPAddr

Returns ip address after a double DNS lookup. First, it will get hostname from a given ip, then resolve the resulting hostname. This policy works because AWS public hostnames resolve to a private ip address within the same datacenter.

Parameters:

  • address (IPAddr) —

    node ip address from Cassandra's system table

Returns:

  • (IPAddr) —

    private ip withing the same datacenter, public ip otherwise. Returns original address if DNS lookups fail.



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# File 'lib/cassandra/address_resolution/policies/ec2_multi_region.rb', line 43

def resolve(address)
  @resolver.each_name(Resolv::DNS::Name.create(address.reverse)) do |name|
    @resolver.each_address(name) do |addr|
      return ::IPAddr.new(addr)
    end
  end

  # default to original address if reverse DNS lookup failed
  address
end