How to set an environment variable in Amazon EC2 - amazon-web-services

Question

I created a tag on the AWS console for one of my EC2 instances.
However, when I look on the server, no such environment variable is set.
The same thing works with elastic beanstalk. env shows the tags I created on the console.
$ env
[...]
DB_PORT=5432
How can I set environment variables in Amazon EC2?

Answer 1

You can retrieve this information from the meta data and then run your own set environment commands.
You can get the instance-id from the meta data (see here for details: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-instance-metadata.html#instancedata-data-retrieval)
curl http://169.254.169.254/latest/meta-data/instance-id
Then you can call the describe-tags using the pre-installed AWS CLI (or install it on your AMI)
aws ec2 describe-tags --filters "Name=resource-id,Values=i-5f4e3d2a" "Name=Value,Values=DB_PORT"
Then you can use OS set environment variable command
export DB_PORT=/what/you/got/from/the/previous/call
You can run all that in your user-data script. See here for details: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/user-data.html

Answer 2

Lately, it seems AWS Parameter Store is a better solution.
Now there is even a secrets manager which auto manages sensitive configurations as database keys and such..
See this script using SSM Parameter Store based of the previous solutions by Guy and PJ Bergeron.
https://github.com/lezavala/ec2-ssm-env

Answer 3

I used a combination of the following tools:
Install jq library (sudo apt-get install -y jq)
Install the EC2 Instance Metadata Query Tool
Here's the gist of the code below in case I update it in the future: https://gist.github.com/marcellodesales/a890b8ca240403187269
######
# Author: Marcello de Sales (marcello.desales#gmail.com)
# Description: Create Create Environment Variables in EC2 Hosts from EC2 Host Tags
#
### Requirements:
# * Install jq library (sudo apt-get install -y jq)
# * Install the EC2 Instance Metadata Query Tool (http://aws.amazon.com/code/1825)
#
### Installation:
# * Add the Policy EC2:DescribeTags to a User
# * aws configure
# * Souce it to the user's ~/.profile that has permissions
####
# REboot and verify the result of $(env).
# Loads the Tags from the current instance
getInstanceTags () {
# http://aws.amazon.com/code/1825 EC2 Instance Metadata Query Tool
INSTANCE_ID=$(./ec2-metadata | grep instance-id | awk '{print $2}')
# Describe the tags of this instance
aws ec2 describe-tags --region sa-east-1 --filters "Name=resource-id,Values=$INSTANCE_ID"
}
# Convert the tags to environment variables.
# Based on https://github.com/berpj/ec2-tags-env/pull/1
tags_to_env () {
tags=$1
for key in $(echo $tags | /usr/bin/jq -r ".[][].Key"); do
value=$(echo $tags | /usr/bin/jq -r ".[][] | select(.Key==\"$key\") | .Value")
key=$(echo $key | /usr/bin/tr '-' '_' | /usr/bin/tr '[:lower:]' '[:upper:]')
echo "Exporting $key=$value"
export $key="$value"
done
}
# Execute the commands
instanceTags=$(getInstanceTags)
tags_to_env "$instanceTags"

Answer 4

If you are using linux or mac os for your ec2 instance then,
Go to your root directory and write command:
vim .bash_profile
You can see your bash_profile file and now press 'i' for inserting a lines, then add
export DB_PORT="5432"
After adding this line you need to save file, so press 'Esc' button then press ':' and after colon write 'w' it will save the file without exiting.
For exit, again press ':' after that write 'quit' and now you are exit from the file. To check that your environment variable is set or not write below commands:
python
>>>import os
>>>os.environ.get('DB_PORT')
>>>5432

Answer 5

Following the instructions given by Guy, I wrote a small shell script. This script uses AWS CLI and jq. It lets you import your AWS instance and AMI tags as shell environment variables.
I hope it can help a few people.
https://github.com/12moons/ec2-tags-env