AWS SSM Session manager client
I am using AWS a lot and I am tired of dealing with everything that comes with the bastion host (additional instance one has to maintain, distribute SSH keys (shared SSH keys are not an option for me), exposing SSH to the network). A while ago, Amazon released a service to fix this - AWS Systems Manager Session Manager. However, CLI user experience of Session Manager is limited and lacks some features:
- ability to connect to instances by other means (e.g. DNS, IP, tag, instance name, autoscaling group) as aws cli supports only connecting by instance IDs
- configuration file support for storing connection information via Session Manager
aws-gate tries to address these issues.
These instructions will get you a copy of the project up and running on your local machine for development and testing purposes. See deployment for notes on how to deploy the project on a live system.
- Python 3.5+ (earlier Python 3 versions should work too)
- session-plugin-manager from AWS
- SSM Agent version 220.127.116.11 or later must be installed on EC2 instances we want to connect to
- Proper IAM permissions for instance profile
pip install aws-gate
or via Homebrew
brew tap xen0l/homebrew-taps brew install aws-gate # For installing session-manager-plugin via Homebrew (optional) brew install --cask session-manager-plugin
or via Docker
docker login docker.pkg.github.com -u $YOUR_GH_USERNAME -p $GH_TOKEN docker pull docker.pkg.github.com/xen0l/aws-gate/aws-gate:latest
config and config.d support
You can store information about to connect to your instance (name, region and profile) and aws-gate will do everything for you. The config file is stored in ~/.aws-gate/config and has the following YAML syntax:
hosts: - alias: backend-pre name: backend profile: preproduction region: eu-west-1 - alias: backend-pro name: backend profile: production region: eu-west-1 defaults: profile: development region: eu-west-1
where hosts stores connection information and defaults default configuration settings to use. To connect to instance backend-pre, execute:
aws-gate session backend-pre
You can place additional configuration files in ~/.aws-gate/config.d. This is ideal when you are working on different projects or when you need to share configuration inside your team.
Querying instances by different instance identifiers
aws-gate supports querying for instances with following identifiers:
- instance id
aws-gate session i-0772e4c1dcdd763b6
- DNS name
aws-gate session ec2-34-245-174-132.eu-west-1.compute.amazonaws.com
- private DNS name
aws-gate session ip-172-31-35-113.eu-west-1.compute.internal
- IP address
aws-gate session 18.104.22.168
- private IP address
aws-gate session 172.31.35.113
aws-gate session Name:SSM-test
- name (uses tag identifier under the hood)
aws-gate session SSM-test
- autoscaling group name (uses tag identifier under the hood)
aws-gate session asg:dummy-v001
SSH ProxyCommand support
AWS SSM Session Manager supports tunneling SSH sessions over it. Moreover, aws-gate supports generating ephemeral SSH keys and uploading them via EC2 Instance Connect API. However, to use this functionality, EC2 Instance Connect setup is needed.
To use this functionality, simply run aws-gate ssh-config, which will generate the required ~/.ssh/config snippet for you:
% aws-gate ssh-config Host *.eu-west-1.default IdentityFile /Users/xenol/.aws-gate/key IdentitiesOnly yes User ec2-user Port 22 ProxyCommand sh -c "aws-gate ssh-proxy -p `echo %h | sed -Ee 's/^(.*)\.(.*)\.(.*)$/\\3/g'` -r `echo %h | sed -Ee 's/^(.*)\.(.*)\.(.*)$/\\2/g'` `echo %h | sed -Ee 's/^(.*)\.(.*)\.(.*)$/\\1/g'`"
Store the snippet inside ~/.ssh/config:
% aws-gate ssh-config >> ~/.ssh/config
Then connect via ssh:
% ssh ssm-test.eu-west-1.default Last login: Fri Oct 4 17:17:02 2019 from localhost __| __|_ ) _| ( / Amazon Linux 2 AMI ___|\___|___| https://aws.amazon.com/amazon-linux-2/ 1 package(s) needed for security, out of 20 available Run "sudo yum update" to apply all updates. [ec2-user@ip-172-31-35-173 ~]$
SSH session to instance ssm-test in eu-west-1 AWS region via default AWS profile is opened.
scp works the same way (both ways):
% # local to remote % scp test_file ssm-test.eu-west-1.glovoapp:test_file test_file 100% 0 0.0KB/s 00:00 % % # remote to local % scp ssm-test.eu-west-1.glovoapp:test_file test_file test_file 100% 0 0.0KB/s 00:00
Please, also note that while scp over SSM works, it can be extremely slow. This is because of the underlying SSM limitations and not caused by aws-gate itself.
aws-gate provides a way to open SSH session on the instance directly. This is achieved by wrapping around ssh under the hood. Simply run aws-gate ssh <instance_identifier>:
% aws-gate ssh ssm-test Last login: Sat Nov 9 10:23:11 2019 from localhost __| __|_ ) _| ( / Amazon Linux 2 AMI ___|\___|___| https://aws.amazon.com/amazon-linux-2/ 28 package(s) needed for security, out of 56 available Run "sudo yum update" to apply all updates. [ec2-user@ip-172-31-35-173 ~]$
If you wish to execute a specific command (or plug it into your shell pipelines):
% aws-gate ssh ssm-test uname -a Linux ip-172-31-35-173.eu-west-1.compute.internal 4.14.123-111.109.amzn2.x86_64 #1 SMP Mon Jun 10 19:37:57 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
Local ports can be forwarded to another host and port relative to the target instance. This works as if by using ssh's
-L option. Instead of executing a command, aws-gate establishes a forwarding session that can be used by other local applications.
For example, you can use this to connect to a private web server by forwarding the instance's local port.
# Terminal 1 % aws-gate ssh -L 8888:localhost:80 ssh-test # Terminal 2 % curl localhost:8888 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"> <head> <title>Test Page for the Nginx HTTP Server on Amazon Linux</title> ...
Or you can use it to connect to a private RDS instance by forwarding the remote address and remote port.
# Terminal 1 % aws-gate ssh -L 3306:privatedb.abcdef123456.eu-west-1.rds.amazonaws.com:3306 ssm-test # Terminal 2 % mysql -h 127.0.0.1 -u root -P 3306 -p -e "SELECT User from mysql.user;" Enter password: +------------------+ | User | +------------------+ | root | | mysql.infoschema | | mysql.session | | mysql.sys | | rdsadmin | +------------------+
If you run into issues, you can get detailed debug log by setting GATE_DEBUG environment variable:
After setting the environment variable, the debug mode will be automatically enabled:
% aws-gate session test 2019-05-26 01:18:23,535 - aws_gate.config - DEBUG - Located config file: /Users/xenol/.aws-gate/config 2019-05-26 01:18:23,538 - aws_gate.utils - DEBUG - Obtaining boto3 session object 2019-05-26 01:18:23,549 - aws_gate.utils - DEBUG - Obtained configured AWS profiles: default development preproduction production 2019-05-26 01:18:23,550 - aws_gate.utils - DEBUG - Obtaining boto3 session object 2019-05-26 01:18:23,560 - aws_gate.utils - DEBUG - Obtained configured AWS profiles: default development preproduction production 2019-05-26 01:18:23,560 - aws_gate.utils - DEBUG - Obtaining boto3 session object 2019-05-26 01:18:23,574 - aws_gate.utils - DEBUG - Obtaining ssm client 2019-05-26 01:18:23,608 - aws_gate.utils - DEBUG - Obtaining boto3 session object 2019-05-26 01:18:23,636 - aws_gate.utils - DEBUG - Obtaining ec2 boto3 resource 2019-05-26 01:18:23,694 - aws_gate.query - DEBUG - Querying EC2 API for instance identifier: SSM-test 2019-05-26 01:18:24,029 - aws_gate.query - DEBUG - Found 1 maching instances 2019-05-26 01:18:24,030 - aws_gate.query - DEBUG - Matching instance: i-0772e4c1dcdd763b6 2019-05-26 01:18:24,030 - aws_gate.session - INFO - Opening session on instance i-0772e4c1dcdd763b6 (eu-west-1) via profile default 2019-05-26 01:18:24,030 - aws_gate.session - DEBUG - Creating a new session on instance: i-0772e4c1dcdd763b6 (eu-west-1) ...
Debug mode also enables printing of Python stack traces if there is a crash or some other problem.
This project is licensed under the BSD License - see the LICENSE.md file for details