Retrieve IP address and port number of EC2 hosting Apache app created via CFT

Question

I want to retrieve the IP addresses of EC2 instances hosting the Apache Solr application getting created through my CFT along with the port number it is running on. I need to pass this information to another stack. Is there any way I can do this?

Answer 1

Generally this is done through CloudFormation Outputs: https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/outputs-section-structure.html

The syntax is shown below:

    "Outputs" : {
      "Logical ID" : {
        "Description" : "Information about the value",
        "Value" : "Value to return",
        "Export" : {
          "Name" : "Value to export"
        }
      }
    }

Or for an example: Here we define a simple EC2 Instance

    "Server" : {
        "Type" : "AWS::EC2::Instance",
        "Properties" : {
        }
    }

And in this statement we are exposing the public ip attribute for the instance.

    "Outputs" : {
        "PublicIp" : {
          "Value" : { "Fn::GetAtt" : [ "Server", "PublicIp" ]},
          "Description" : "Server's PublicIp Address"
        }
    }

(examples gotten from this issue: AWS CloudFormation: How to output a machine's PublicIP? Credit should go to: Matt Houser)

By default Solr runs on port: 8983 so unless this is not the case, this can probably be used.

In that case your Outputs might look like this:

    "Outputs" : {
        "PublicIp" : {
          "Value" : { "Fn::GetAtt" : [ "Server", "PublicIp" ]},
          "Description" : "Server's PublicIp Address"
        },
        "SolrPort" : {
          "Value" : "8983",
          "Description" : "Port that Solr is running on."
        }
    }