Create EC2 instance and get public IP when available - bash

Question

I have a monotonous work of creating an ec2 instance from an AMI and then ssh into it and run a crypto bot to get a sub domain SSL certificates for it and then run some frontend and backend onto it.
I would like to automate this...
I am able to create the EC2 instance
aws ec2 run-instances --image-id ami-0bef9cfcxxxxxx --count 1 --instance-type t2.medium --key-name MyKey --security-group-ids SG-1 --tag-specifications 'ResourceType=instance,Tags=[{Key=Name,Value=SubDomain}]'
but how do I wait till the instance is UP and get the public IP for the next steps?
Any suggestions would help,
Thanks!

Answer 1

Assuming you know the target instance id, you can query your instance and get the current state, instanceId, name (assuming you tagged them with a name) and public IP via something like:
aws ec2 describe-instances \
--instance-ids YOUR_TARGET_INSTANCE_ID \
--query "Reservations[*].Instances[*].[State.Name, InstanceId, Tags[?Key==\`Name\`]|[0].Value, PublicIpAddress]" \
--output text
You could run this query in a loop until the status comes back as running and then capture the public ip address:
while :
do
output=$(aws ec2 describe-instances \
--instance-ids YOUR_TARGET_INSTANCE_ID \
--query "Reservations[*].Instances[*].[State.Name, InstanceId, \
Tags[?Key==\`Name\`]|[0].Value, PublicIpAddress]" \
--output text)
if [[ "${output}" == running* ]] ; then
cut -d $'\t' -f4- <<<"${output}"
break
fi
done
Note:
The aws ec2 queries are all using the default AWS profile. You can specify a different profile via --profile your_target_profile_name if needed.
If you do not know your target instance id, you can remove the --instance-id portion of the aws ec2 query and list all of your instances (in your default region). You could choose the required instance id from that list.