auto-scaling re-launcher

user-data.txt

#!/bin/bash

set -o errexit -o errtrace -o pipefail
trap signal_and_exit ERR

function my_instance_id
{
  curl -sL http://169.254.169.254/latest/meta-data/instance-id/
}

function my_az
{
  curl -sL http://169.254.169.254/latest/meta-data/placement/availability-zone/
}

function my_aws_region
{
  local az
  az=$(my_az)
  echo "${az%?}"
}

# Signaling that this instance is unhealthy allows AWS auto scaling to launch a copy 
# Provides for self healing and helps mitigate transient failures (e.g. package transfers)
function signal_and_exit
{
  status=$?
  if [ $status -gt 0 ]; then
    sleep 180 # give me a few minutes to look around before croaking
    /usr/local/bin/aws autoscaling set-instance-health \
      --instance-id "$(my_instance_id)" \
      --health-status Unhealthy \
      --region "$(my_aws_region)"
  fi
}

#-----^ AWS safety guards ^-----

# All of this, just to install python-pip.
for i in rhscl extras optional ; do 
  yum-config-manager --enable rhui-REGION-rhel-server-$i > /dev/null 2>&1
done
sudo rpmkeys --import https://getfedora.org/static/352C64E5.txt
rpm -i https://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm

yum -y install python-pip setuptools awscli

curl -L https://bootstrap.saltstack.com -o install_salt.sh
sh install_salt.sh -A salt.ivytech.edu -L