Automated DNS Record Creation with AWS Route 53 and Bash Script

This is an useful script for automating the process of creating DNS records using the AWS Route 53 service.

First, there's a list of items in the format "name, domain, IP, hosted zone ID". Each item represents a DNS record to be created.

firewall,acme.com.br,10.1.1.1,00000000000000 	
gitlab,acme.com.br,10.1.1.163,00000000000000 
hyoga,acme.com.br,10.1.1.17,00000000000000 	
ikki,acme.com.br,10.1.1.98,00000000000000 		
marin,acme.com.br,10.1.1.163,00000000000000 
milo,acme.com.br,10.1.1.193,00000000000000
proxy,acme.com.br,10.1.1.82,00000000000000 	
saga,acme.com.br,10.1.1.6,00000000000000 	
seiya,tex.com.br,10.1.1.76,11111111111111 	
shaka,tex.com.br,10.1.1.2,11111111111111  
shina,tex.com.br,10.1.1.4,11111111111111  	
shion,tex.com.br,10.1.1.9,11111111111111  
shun,tex.com.br,10.1.1.94,11111111111111  		
shura,tex.com.br,10.1.1.8 ,11111111111111 	
storage,tex.com.br,10.1.1.5,11111111111111  
wiki,tex.com.br,10.1.1.88,11111111111111 

Bash Script:

#!/bin/bash

for I in `cat /tmp/list`; do
    aws route53 change-resource-record-sets \
      --hosted-zone-id $(echo $I | cut -d ',' -f4) \
      --change-batch '
      {
        "Comment": "Testing creating a record set"
        ,"Changes": [{
          "Action"              : "CREATE"
          ,"ResourceRecordSet"  : {
            "Name"              : "'$(echo $I | cut -d ',' -f1).$(echo $I | cut -d ',' -f2)'"
            ,"Type"             : "CNAME"
            ,"TTL"              : 120
            ,"ResourceRecords"  : [{
                "Value"         : "'$(echo $I | cut -d ',' -f3)'"
            }]
          }
        }]
      }
    '
done

Let me break it down for you:

• Then, there's a Bash script starting with #!/bin/bash, indicating it's a Bash script.
• Inside the script, there's a for loop iterating over each line of the file /tmp/list. It's using backticks to execute the cat /tmp/list command and iterate over its output.
• For each line in the list, it's executing the AWS CLI command aws route53 change-resource-record-sets to create a DNS record.
• The aws route53 change-resource-record-sets command is being supplied with parameters:
  • --hosted-zone-id: The hosted zone ID extracted from the input line.
  • --change-batch: A JSON string specifying the changes to be made. This JSON includes:
    • A comment.
    • An array of changes, each containing:
      • The action (in this case, "CREATE").
      • Details of the resource record set to be created, including:
        • Name: Constructed from the name and domain fields of the input line.
        • Type: Always "CNAME" in this script.
        • TTL: Time to Live for the DNS record.
        • ResourceRecords: An array containing the IP address extracted from the input line.
• Inside the JSON, the values for name, type, TTL, and IP address are extracted from the input line using cut commands.
• The script repeats this process for each line in the list, effectively creating a DNS record for each item in the list.

This script essentially automates the creation of DNS records based on the information provided in the list file.