Convert an AWS Route53 Resource Record Set to point to an Alias Target
Occasionally, you’ll want to change a Route53 Resource Record Set from one type to another. In the case of going from a traditonal ‘A’ record to an Alias Target the following code (with the aws-sdk rubygem) should do the trick.
The gotcha with this process is the need to unset ttl and resource_records as a part of the update.
zone = AWS::Route53.new.hosted_zones.select { |z| z.name == 'example.com.' }.first # find zone by name
rrset = zone.rrsets.create('jedi.example.com.', 'A', { :ttl => 60, :resource_records => [{ :value => '127.0.0.1' }] })
# Now lets update it to be an alias target
stack = AWS::CloudFormation.new.stacks['jedi-stack'] # assuming the stack exists
lb_resources = stack.resources.select {|x| x.resource_type == 'AWS::ElasticLoadBalancing::LoadBalancer' }
lb_resource = lb_resources.first
lb = AWS::ELB.new.load_balancers[lb_resource.physical_resource_id]
rrset.alias_target = { dns_name: lb.canonical_hosted_zone_name, hosted_zone_id: lb.canonical_hosted_zone_name_id, evaluate_target_health: false }
rrset.ttl=nil if rrset.ttl
rrset.resource_records=nil if rrset.resource_records
rrset.updateYou should now have a RRSet pointed at your ELB.