Saturday, October 28, 2017

Instance does not have a volume attached at root (/dev/sda1)

Error :Instance does not have a volume attached at root (/dev/sda1) 

The error occurs when either a boot volume is missing or mapped to wrong device name. In this case EC2 instance is expecting the boot device name /dev/sda1 to be connected to the EC2 instance and unable to find it

The step is valid for EC2 instances is backed by EBS volumes i.e EBS is used for boot volumes rather than Instance Store

Note: To Understand more about Instance backed store and EBS backed store
refer this article Amazon EC2 Root Device Volume

To attach a root volume follow these steps.

  • Create   a new EBS Volume. Click on Volumes when in EC2 Instance page

  • Once EBS volume is created , right click and select Attach Volume
  • Select the EC2 instance in second textbox and enter the device name as "/dev/sda1"

  • Click Attach and restart the EC2 instance 

 Do leave comment if the solution works and even if it doesn't work . Thanks!

node -v ReferenceError: node is not defined

Trying to make node.js work with command node -v and end up with an error 

node -v ReferenceError: node is not defined 

You are probably trying to run the command in REPL  virtual environment

In order to check node.js version go to the folder with node.js files and run command from command prompt 

About REPL 

REPL ( Read- Eval-Print -Loop) is an virtual environment that comes with Node.js. It is tool to test simple Node.js javascript code. 

Gray Failures: What is it and how to detect one?

If you are reading this article , i guess you are curious to know about gray failures and different methods to detect gray failures.  Hopefu...