Cloudwatch Cloudformation Centos 7.2 RHEL UserData for Adding Memory Utilization Reporting to Alarm on MemoryUtilization

UserData.json

{
  "UserData": { "Fn::Base64": { "Fn::Join": ["", [
    "#!/bin/bash\n",
    "cd /root \n",
    "sudo yum install perl-Switch perl-DateTime perl-Sys-Syslog perl-LWP-Protocol-https perl-Digest-SHA -y\n",
    "sudo yum install zip unzip -y \n",
    "curl https://aws-cloudwatch.s3.amazonaws.com/downloads/CloudWatchMonitoringScripts-1.2.2.zip -O \n",
    "unzip CloudWatchMonitoringScripts-1.2.2.zip \n",
    "rm CloudWatchMonitoringScripts-1.2.2.zip \n",
    "cd aws-scripts-mon \n",
    "cp awscreds.template awscreds.conf \n",
    "(crontab -l 2>/dev/null; echo \"*/1 * * * * /root/aws-scripts-mon/mon-put-instance-data.pl --mem-used-incl-cache-buff --mem-util --mem-used --mem-avail\") | crontab - \n"
  ]]}}
}

Tested on Centos 7.2, this script in Userdata will install the appropriate Perl requirements to run the monitor script, as well as add a cron to report Memory data every minute to Cloudwatch. This is useful for researching memory leaks, or rebooting EC2s when they are memory exhausted using a Cloudwatch alarm on what this script reports.

Note that your instance will either require an IAM role granted to the EC2, or credentials placed in that awscreds.conf on ln 11, that have access to the following:

[{
   "Action": "cloudwatch:PutMetricData",
   "Effect": "Allow",
   "Resource": "*"
  },
  {
    "Action": "cloudwatch:GetMetricStatistics",
    "Effect": "Allow",
    "Resource": "*"
  },
  {
   "Action": "cloudwatch:ListMetrics",
   "Effect": "Allow",
   "Resource": "*"
}]