Execute MyGarage builds on EC2 Instance

After being able run my app on Ubuntu as a service, I wanted to move my build process to cloud as well. So, first, I installed Jenkins on the AWS EC2 Machine.

Now when I run a job in jenkins, it should use one of the EC2 instance as its slave and complete build. For this I used EC2 Plugin which allows to setup any EC2 instance as a jenkins slave.

There are several articles on how to configure this plugin, However, I followed this video where its clearly explained which configurations are needed to setup EC2 instance as jenkins slave.

The advantage with this approach is that only when a jenkins job is started, a new EC2 instance of the alerady defined configuration is spawned. This is treated as jenkins slave and job is completed. We do have the option to set Idle time ex: 5 or 10 mins. So if there is no other job requesting any EC2 instance for job execution the instance is automatically terminated.

For most of the simple jobs t2 micro is enough.

A few important observations when i did this experiment:

1. When the EC2 instance is created it took several minutes to connect via ssh. sometimes delay was due to job not being able to read from the EC2 console. I had to try setting different values to Host Key Verification Strategy field in the plugin. ‘check-new-soft’ or ‘accept-new’ values worked for me. More details can be found in the plugin page under Security section here

2. Another challenge was that my EC2 instances were getting created and terminated within a minute without executing job. I spent good amount of time to figure out the cause. Later I noticed one difference, I was using Ubuntu as master to spawn slaves. When I changed the AMI ID to Amazon Linux it worked flawlessly. One reason is that Amazon Linux installs Java if its not installed by itself. I am still trying to make it work with Ubuntu

So, now whenever I trigger a job in my jenkins my build is running on a On Demand EC2 instance.

Next, i am working with Spot Instances, will list my observations in next blog