AutoScaler - AWS AutoScaling Configuration Tool

In a nutshell

Creating and managing a large number of Launch Configurations and AutoScaling Groups can be a pain. AutoScaler aims to make it easier.

Command line

Create a new launch configuration with the ability to override default values.

It should be noted that AutoScaler is not actually editing the launch configuration since that is not available in the AutoScaling API. What AutoScaler is actually doing is:

• creating a temporary launch configuration with the new values
• moving over all autoscaling groups to the temporary configuration
• deleting the original launch configuration
• creating a replacement launch configuration with the same name
• moving over all autoscaling groups to the replacement configuration
• deleting the temporary configuration

There is also autoscaler_auto_scaling_group which has the same interface for AutoScaling groups.

You must set AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY environment variables properly for this to work.

Default Launch Config

In order for the default values to work, you must create a launch configuration with the name "autoscaler_default". This is where the default values will be pulled from. If there is no such launch configuration, the defaults will just be blank.

Python Interface

from autoscaler import add_launch_config, edit_launch_config

add_launch_config("web", user_data="echo 'web_machine' > /etc/config")

edit_launch_config("web", image_id='ami-abcd1234')

Block Device Mappings

A custom syntax has been added to create Block Device Mappings from the command line and convert those to Python objects.

The tested format can be found in tests/test_parsers.py but the abbreviated form is available here. All examples show the expected user input.

General Format

# Ephemeral Drive
user_input = "[mount_point]=[ephemeral_drive]"
# EBS Drives
user_input = "[mount_point]=[snapshot]:[size]:[delete_on_termination]:[iops]"

Ephemeral Drive

# Note ephemeral[0-7] corresponds to the AWS ephemeral disk mapping
user_input = "/dev/xvdb=ephemeral0"

EBS Drive

# Snapshot Drive (preserves size)
user_input = "/dev/xvdf=snap-1234abcd"

# 100GB Drive
user_input = "/dev/xvdf=:100"

# 100GB Snapshot Drive
user_input = "/dev/xvdf=snap-1234abcd:100"

# 100GB Drive without 'Delete on Termination'
user_input = "/dev/xvdf=:100:false"

# 100GB Drive with 1000 IOPS and no 'Delete on Termination'
user_input = "/dev/xvdf=:100:false:1000"

# 100GB Drive with 1000 IOPS and default 'Delete on Termination'
user_input = "/dev/xvdf=:100::1000"

Install

$ pip install autoscaler