Set environment variables in an AWS instance

Question

I create an AMI in EC2 with terraform with this resource:

resource "aws_instance" "devops-demo" {
  ami           = "jnkdjsndjsnfsdj"
  instance_type = "t2.micro"
  key_name      = "demo-devops"
  user_data     = "${file("ops_setup.sh")}"
}

The user data executes a shell script that install Java JRE:

  sudo yum remove java-1.7.0-openjdk -y
  sudo wget -O /opt/server-jre-8u172-linux-x64.tar.gz --no-cookies --no-check-certificate --header "Cookie: gpw_e24=http%3A%2F%2Fwww.oracle.com%2F; oraclelicense=accept-securebackup-cookie" "http://download.oracle.com/otn-pub/java/jdk/8u172-b11/a58eab1ec242421181065cdc37240b08/server-jre-8u172-linux-x64.tar.gz"
  sudo tar xzf /opt/server-jre-8u172-linux-x64.tar.gz
  export JAVA_HOME=/jdk1.8.0_172
  export JRE_HOME=/jdk1.8.0_171/jre
  export PATH=$JAVA_HOME/bin:$PATH

But none of the environment variables work. However, if I connect by ssh to the instance and I execute the export command, it works fine.

Is there any way to define the environment variables with terraform?

Answer 1

Using the export command only sets those variables for the current shell and all processes that start from that shell. It is not a persistent setting. Anything you wish to make permanent should be set in /etc/environment.

For example in userdata:

echo "JAVA_HOME=/jdk1.8.0_172" >> /etc/environment

This would add the JAVA_HOME=/jdk1.8.0_172 line to that file. Note, you should not use export inside that file.

The PATH variable is likely already defined in the /etc/environment file and you'll need to overwrite that appropriately if you are going to append additional paths to it.

There is really great details on setting environment variables available in this answer.