Autoscaling with EC2 and Chef

Dear all,

It has been a long time since my last post and here I am with a new one, just to keep track of my current study case…

I would like to put in place an auto-scaling mechanism for my lab platform.

Currently I have one Ha-Proxy load balancer with 2 backends. I will perform stress test on my front-end  with Jmeter and create automatically a virtual machine joined to my Chef infrastructure in order to increase resources.

In this post I will describe just how to set  up an initial configuration of autoscaling-group + Chef ( today it is Friday… on Monday I will do the rest 😉

Let’s start  with the needed components:

  1. a Chef server
  2. one HaProxy load balancer
  3. two tomcat backend

Now I try the script for the unattended bootstrap. This script adds a new node under the Chef Server. I tried it on a simple virtual machine locally, using a Centos 7 running in Virtualbox.

[ ! -e /etc/chef ] && mkdir /etc/chef

cat <<EOF > /etc/chef/validation.pem
your super secret private key :)

cat <<EOF > /etc/chef/client.rb
log_location STDOUT
chef_server_url "https://mychefserver.goofy.goober/organizations/myorg"
ssl_verify_mode :verify_none
validation_client_name "myorg-validator"

cat <<EOF > /etc/chef/first-boot.json

 "run_list": ["role[tomcat_backend]"]


curl -L | \
bash -s -- -v 12.9.41 &> /tmp/get_chef.log
chef-client -E amazon_demo -j /etc/chef/first-boot.json  \
&> /tmp/chef.log 

If things have done correctly you will see the new node into your Chef server dashboard..Check the logs on the new node in case of problems..


Now let’s create the autoscaling-group in Amazon EC2

Screen Shot 2016-05-06 at 13.43.35.png

Then select your preferred instance… I am using RHEL 7.2

Screen Shot 2016-05-06 at 13.44.48.png

Insert the bootstrap script “User data file” (the one we just created)

Screen Shot 2016-05-06 at 13.49.17.png

I have no instances running on my cloud, so the following configuration will generate a virtual machine due to the min required is 1.

Screen Shot 2016-05-06 at 17.42.56.png

After a minute I got an email saying:

Description: Launching a new EC2 instance: $my_id_istance
Cause: At 2016-05-06T15:10:17Z an instance was started in response to a 
difference between desired and actual

Finally I have a new configured node in my Chef server.. . which is the autoscaling_node01.

Screen Shot 2016-05-06 at 16.00.44.png

That’s all folks!

Bye for now…

Eugenio Marzo
DevOps Engineer at SourceSense



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