How to EC2 disk and memory usage monitoring

Approach1. Using awscli (you don't have to make codes)

1. before collecting some metrics from your instance, your instance must be lauched with CloudWatchFullAccess IAM role.

ref: http://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/UsingIAM.html

Amazon CloudWatch integrates with AWS Identity and Access Management (IAM) so that you can specify which CloudWatch actions a user in your AWS Account can perform. For example, you could create an IAM policy that gives only certain users in your organization permission to use GetMetricStatistics. They could then use the action to retrieve data about your cloud resources.

* in my  case, I made new role(named cloudwatch_test) on IAM service with CloudWatchFullAccess, CloudWatchLogsFullAccess policies. and launch ec2 instance with this IAM role. 

2. follow this. to install cloudwatch tool stuffs

http://docs.aws.amazon.com/AmazonCloudWatch/latest/DeveloperGuide/mon-scripts-perl.html

3. After installing perl stuffs and finishing role settings, you can use perl command like this.

$ sudo mv aws-scripts-mon /usr/local/bin/aws-scripts-mon
$ echo "* * * * * ubuntu /usr/local/bin/aws-scripts-mon/mon-put-instance-data.pl --mem-used --mem-avail --disk-path=/dev/xvda1 --disk-space-used --dis-space-avail --from-cron" | sudo tee /etc/cron.d/aws-monitor-mem-disk-usage

* "ubuntu" is user name 

now you can check your custom metric in Ec2 monitoring->View all CloudWatch metrics->Metrics-> Linux System Metrics

* if you want to monitor your existing ec2 instance, unfortunately there is no way. I tried below, but it was not working.

(you should install awscli tool first, just type $sudo apt-get install awscli, $aws configure)

1. aws iam create-instance-profile --instance-profile-name CloudWatchProfile

2. aws iam add-role-to-instance-profile --instance-profile-name CloudWatchProfile --role-name cloudwatch_test

Approach2. Using Boto (you have to do some works, but could be more flexible)

http://arr.gr/blog/2013/08/monitoring-ec2-instance-memory-usage-with-cloudwatch/

followed record.

1. make t2 micro ec2 instance (ubuntu)

2. install prerequisites

$sudo apt-get update

$sudo apt-get install python-pip

$sudo pip install boto

3. setup boto config file

$sudo vim /etc/boto.cfg

[Credentials]
aws_access_key_id = <your_access_key_here>
aws_secret_access_key = <your_secret_key_here>

4. get source code and set to cron job

$ curl https://gist.githubusercontent.com/shevron/6204349/raw/cw-monitor-memusage.py | sudo tee /usr/local/bin/cw-monitor-memusage.py
$ sudo chmod +x /usr/local/bin/cw-monitor-memusage.py
$ echo "***** ubuntu /usr/local/bin/cw-monitor-memusage.py" | sudo tee /etc/cron.d/cw-monitor-memusage

* "ubuntu" is user name 

5. check it in AWS management console
Ec2 monitoring->View all CloudWatch metrics->Metrics-> Custom Metrics (it will take a time, wait until this menu created)