Category: RDS

AWS EC2 Elastic Beanstalk Going to Sleep – .Net/Windows/MSSQL Server Express

Hi everyone,

I’ve been having a bit of an issue with my AWS app going to sleep and taking a long time to handle initial requests.

I’m using .NET with Elastic Beanstalk on a T2 Micro Instance and MSSQL Server Express on RDS. My FrontEnd is a static ReactJS app that sits in S3 behind CloudFront. There’s also a load balancer across the backend.

My frontend was always instant but my initial Api calls were timing out. This ruled out S3 and CloudFront, leaving the following:

  • Load balancer
  • RDS/MSSQL
  • EC2/IIS

After a bit of Googling I came across something that looked fairly promising – MSSQL Server Express has a property called AutoClose set to ‘ON’ by default. AWS appears to correct this as mine was off however it’s worth checking:

-- If set to zero then auto close is off
SELECT DATABASEPROPERTY('mydatabasename','IsAutoShrink')

-- Check all instances at once
SELECT name,is_auto_close_on FROM sys.databases

-- Turn off if on
ALTER DATABASE myDB SET AUTO_CLOSE OFF

In my case the actual problem turned out to be IIS idle timeout. By default IIS automatically times out an application after 20 minutes. In order to disable this create the following ebextension:

commands:
    setIdleTimeoutToZero:
        cwd: "C:\windows\system32\inetsrv"
        command: "appcmd set apppool /apppool.name:DefaultAppPool /.processModel.idleTimeout:0.00:00:00"

If you haven’t done this before, all you need to do is create a folder called .ebextensions under your project directory. Then create a new file called iis-idle-timeout.config and add the yaml to it. If you need more information on iis timing out check out this great blog post: https://notebookheavy.com/2017/06/21/set-iis-idle-timeout-elastic-beanstalk/

Thanks to these sources for the solutions:
Disable auto_close: https://stackoverflow.com/a/1750400/522859
IIS Timeout: https://notebookheavy.com/2017/06/21/set-iis-idle-timeout-elastic-beanstalk/
EBExtension Info: http://notebookheavy.com/2017/05/01/auto-install-newrelic-agent-elastic-beanstalk/

Unable to Access RDS Database from Elastic Beanstalk Application

Hey everyone,

I ran into a bit of an issue today where I was unable to access my RDS SQL Express instance from my .NET Elastic Beanstalk instance. I was receiving the following error:

The server was not found or was not accessible.

The solution turned out to be fairly simply thanks to this StackOverflow post: http://stackoverflow.com/a/33207022/522859

Get your server instance security group:
– Log into AWS
– Navigate to elastic beanstalk
– Open your application instance
– Open configuration
– Open instances
– Find “server” on the page and copy the value in the “EC2 security groups” field

Add your server instance security group to your rds rules:
– Navigate to the RDS Dashboard
– Open your RDS instance
– Click on view details (left hand side or top)
– Find Security and Network
– Click on the rds-launch-wizard under security groups
– Click on inbound rules (very bottom currently)
– Add a new inbound rule with the copied security group as the source