After getting frustrated, I thought of getting this fixed on a permanent basis. Using my knowledge of shell scripting and basic AWS CLI commands, I have created a shell script to do this automatically.
What does this script do?
1. Get instance id from AutoScallingGroup
2. Get launch configuration name from AutoScallingGroup
3. Create AMI from the instance which gets in step 1
4. Create a new Launch Configuration
5. Update Auto Scaling Group to use newly created Launch Configuration
6. Delete old Launch Configuration
How to choose a specific instance from ASG?
In that case, you can specify the instance ID as well along with the autoscaling group name. The script will then create it’s AMI and update the launch configuration.
And Finally below is the shell script
#!/bin/bash
#Define parameters
ASG_NAME="myapp"
NEW_LC="myapp-$(date +%Y-%m-%d_%H-%M)"
TIME=$(date +%Y-%m-%d_%H-%M)
echo "Selected Auto Scaling Group is ${ASG_NAME}"
# Get instance id from ASG_NAME
RANDOM_INST_ID="$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-names ${ASG_NAME} --query 'AutoScalingGroups[].Instances[?HealthStatus==`Healthy`].InstanceId' | head -3 | sed 1d | sed 1d | sed 's/ //g' | sed 's/"//g')";
# Get launch configuration name from ASG_NAME
LC_NAME=$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-names ${ASG_NAME} --query 'AutoScalingGroups[].LaunchConfigurationName' | head -2 | sed 1d | sed 's/ //g' | sed 's/"//g')
# Create AMI
IMAGE=`aws ec2 create-image --instance-id ${RANDOM_INST_ID} --name NEW-IMAGE-${TIME} --no-reboot --output text`
echo "Create Image of instance ${RANDOM_INST_ID}"
# Create Launch Configuration
aws autoscaling create-launch-configuration --launch-configuration-name ${NEW_LC} --image-id ${IMAGE} --instance-type t2.micro --key myapp --associate-public-ip-address --security-groups sg-0123456ghbh79
echo "create new Launch Configuration ${NEW_LC}"
# Update Auto Scaling Group to use new Launch Configuration
aws autoscaling update-auto-scaling-group --auto-scaling-group-name ${ASG_NAME} --launch-configuration-name ${NEW_LC}
echo "New Launch Configuration is updated in ASG ${NEW_LC}"
# Delete old Auto Scaling Launch Configuration
aws autoscaling delete-launch-configuration --launch-configuration-name ${LC_NAME}
echo "Delete old Launch Configuration"
echo "SUCCESS!"
For update script visit: https://github.com/SubhashPatel/change-ami-launch-config.sh/tree/master
