问识别ECS实例的硬编码DNS记录

EN

## --------------------------------------------------------------------------------------------------------------- ##
## --- AUTO SCALING LOGIC for user-data -------------------------------------------------------------------------- ##
## --------------------------------------------------------------------------------------------------------------- ##
## --- Get ip addresses of existing app DNS Entries (that point to app nodes, not load balancer) ----- ##
## --- Get this ip address --------------------------------------------------------------------------------------- ##
## --- If this IP Address matches any in existing list, do not create a new DNS record --------------------------- ##
## --- If this IP Address does not match any in existing list, create a new DNS record --------------------------- ##
## --------------------------------------------------------------------------------------------------------------- ##

region="us-east-1"
hosted_zone="ROUTE53-HOSTED-ZONE-ID"
vpc="vpc-ID"
r53_domain="example.com"
asg_desired="2"
application="app"

echo "USING EC2 INSTANCE META DATA TO OBTAIN IP ADDRESS ..."
echo "IF YOU ARE NOT USING DEFAULT AMZN INSTANCE, USE ifconfig OR ANOTHER METHOD TO OBTAIN THIS INSTANCE IP ..."

# CHOOSE THE PRIVATE (local-ipv4) OR PUBLIC IP DEPENDING ON USE CASE 
#this_ip=`curl http://169.254.169.254/latest/meta-data/local-ipv4`
this_ip=`curl http://169.254.169.254/latest/meta-data/public-ipv4`
echo $this_ip > /tmp/this-ip.txt

# FILTER BASED ON UNIQUE TAGS FOR YOUR TARGETED INSTANCE(S)
# THIS IS USING Application Tag. 
aws --region $region ec2 describe-instances --query "Reservations[*].Instances[? Tags[? (Key=='Application') && Value=='$application']].PublicIpAddress" --output text >> /tmp/existing-ec2-ips.txt

counter=1
until [ $counter -gt $asg_desired ]
do
  aws --region $region route53 list-resource-record-sets --hosted-zone-id $hosted_zone --query "ResourceRecordSets[?Name == 'instance-$counter.$r53_domain.'].ResourceRecords" --output text >> /tmp/existing-ips.txt
  aws --region $region route53 list-resource-record-sets --hosted-zone-id $hosted_zone --query "ResourceRecordSets[?Name == 'instance-$counter.$r53_domain.']" --output text >> /tmp/existing-records.txt
  ((counter++))
done

diff /tmp/existing-ips.txt /tmp/this-ip.txt

echo "Does this instance IP exist in a $application route53 record?"
this_ip_result=`grep $this_ip /tmp/existing-ips.txt | wc -l`

if [[ $this_ip_result -gt 0 ]]
then
  echo "Yes, this instance IP already exists in a $application route53 record."
  echo "Nothing left to do"
else
  echo "No, this instance IP does not exist in a $application route53 record."
  echo "Adding route53 record... "
  counter=1
    until [ $counter -gt $asg_desired ]
    do
        grep -L instance-$counter.$r53_domain /tmp/existing-records.txt > /tmp/instance-$counter.$r53_domain.txt
        if [ -s /tmp/instance-$counter.$r53_domain.txt ]
            then
                echo "instance-$counter.$r53_domain does not exist... Adding!"
                aws --region $region route53 change-resource-record-sets --hosted-zone-id $hosted_zone --change-batch '{ "Comment": "Auto Scaling Creating Record Set", "Changes": [ { "Action": "CREATE", "ResourceRecordSet": { "Name": "instance-'$counter'.'$r53_domain'", "Type": "A", "TTL": 120, "ResourceRecords": [ { "Value": "'"$this_ip"'" } ] } } ] }'
            else
                echo "Updating Record Set!"
                echo "Updating Route53 Records with the following IPs ..."
                diff /tmp/existing-ec2-ips.txt /tmp/existing-ips.txt | grep ">" | sed 's/> //g'
                ip_update=`diff /tmp/existing-ec2-ips.txt /tmp/existing-ips.txt | grep ">" | sed 's/> //g'`
                record_update=`grep -B 1 $ip_update /tmp/existing-records.txt | grep $application | awk '{print $1}' | awk 'FNR == 1 {print}'`
                aws --region $region route53 change-resource-record-sets --hosted-zone-id $hosted_zone --change-batch '{ "Comment": "Auto Scaling Updating Record Set", "Changes": [ { "Action": "UPSERT", "ResourceRecordSet": { "Name": "'"$record_update"'", "Type": "A", "TTL": 120, "ResourceRecords": [ { "Value": "'"$this_ip"'" } ] } } ] }'
            fi
        ((counter++))
    done
fi