Why does aws code deploy throw "No passwd entry for user 'ec2-user'" error inspite of running everything as root?

Here are the error messages:

Here are the concerned files:

stop.sh

#!/bin/bash
pkill -f node

appspec.yml

version: 0.0
os: linux
files:
  - source: /
    destination: /var/www/
permissions:
  - object: /var/www/
    owner: root
    mode: 777
hooks:
  BeforeInstall:
    - location: scripts/install.sh
      timeout: 300
      runas: root
  AfterInstall:
    - location: scripts/post_install.sh
      timeout: 300
      runas: root
  ApplicationStart:
    - location: scripts/run.sh
      timeout: 300
      runas: root
  ApplicationStop:
    - location: scripts/stop.sh
      timeout: 300
      runas: root
  ValidateService:
    - location: scripts/validate.sh
      timeout: 300
      runas: root

Here are the OS detail:

ubuntu@ip-172-31-2-33:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.1 LTS
Release:    14.04
Codename:   trusty

I tried running all hooks as ec2-user 'ubuntu' as well, results are the same.

via ishandutta2007