In a
previous blog entry, I created a web-service using Jersey that calculates the area of various shapes. In this entry, I deploy the web-service to AWS using Elastic Beanstalk.
Running the Jersey web service on
Elastic Beanstalk was fairly straight forward. I followed the
instructions for creating a new application. However, I did come across an issue with the health check, that required some slight tweaking.
Health Check
Beanstalk will send a health check to your application. By default, the application health check URL is the application root (e.g., http://myapp.elasticbeanstalk.com/) and it expects a response of 200 OK for the application to be considered healthy.
With my application, the root will return a 405 response. However, Beanstalk will let you configure the health check url. So, I decided to implement a health check method for Beanstalk to call. I could have setup the health check url to call one of the existing methods (i.e. call the square method), but I figured a health check method would be better. I added the following method to the "CalculateAreaResource" class
@Path("/healthcheck")
@GET
@Produces(MediaType.TEXT_HTML)
public String healthCheck() {
return Response.Status.OK.name();
}
I then set the url health check in Elastic Beanstalk to "/calculate/area/healthcheck". However, my beanstalk environment failed to build with the error:
Your health check URL may be misconfigured. If your application does not respond to requests at http://calculate.elasticbeanstalk.com:80/calculate/area/healthcheck, modify the health check URL to a valid path.
Fixing the Health Check URL
I knew from running locally that http://localhost:8080/calculate/area/healthcheck worked, so I ssh'd into the ec2 instance. Checking the tomcat log files and web-app directory, I noticed that my war was deployed as the ROOT web-app and not into the "calculate" context as I had been using locally. (Note: the tomcat directory is in /opt/tomcat7)
I modified the url health check in the Elastic Beanstalk settings from "/calculate/area/healthcheck" to
"/area/healthcheck" and restarted the environment. It loaded properly and I could access my web service!
For details on how to ssh into your instance, please see the reference links below.
References:
