Packer and package installs

Problem: 

When using Packer to generate an Ubuntu AWS AMI, I use a shell script provisioner to install and update packages via apt-get. When executing apt commands in the script, I was getting the errors such as: 

"Package has no installation candidate"

"Unable to locate package" 

 Solution: 

The error in the shell script was that I was executing apt-get commands before the AWS cloud-init completed.

To check that cloud-init finished before running apt-get, modify the script via

while [ ! -f  /var/lib/cloud/instance/boot-finished ];

do

    echo "Waiting for cloud-init to finish ..."

    sleep 2

done

apt-get update -y

apt-get install -y package