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Chef knife plug-in for AWS EC2
Latest commit e6b1f52 @NimishaS NimishaS Merge pull request #375 from chef/btm/attach-nic
Attach network interfaces before bootstrap

Knife EC2

Gem Version Build Status Dependency Status

This is the official Chef Knife plugin for Amazon EC2. This plugin gives knife the ability to create, bootstrap, and manage EC2 instances.


If you're using ChefDK, simply install the Gem:

$ chef gem install knife-ec2

If you're using bundler, simply add Chef and Knife EC2 to your Gemfile:

gem 'knife-ec2'

If you are not using bundler, you can install the gem manually from Rubygems:

$ gem install knife-ec2

Depending on your system's configuration, you may need to run this command with root privileges.


In order to communicate with the Amazon's EC2 API you will need to pass Knife your AWS Access Key, Secret Access Key, and if using STS your session token. This can be done in several ways:

Knife.rb Configuration

The easiest way to configure your Amazon EC2 credentials for knife-ec2 is to specify them in your your knife.rb file:

knife[:aws_access_key_id] = "Your AWS Access Key ID"
knife[:aws_secret_access_key] = "Your AWS Secret Access Key"

Additionally if using AWS STS:

knife[:aws_session_token] = "Your AWS Session Token"

Note: If your knife.rb file will be checked into a source control management system, or is otherwise accessible by others, you may want to use one of the other configuration methods to avoid exposing your credentials.

Environmental Variables

Knife-ec2 can also read your credentials from shell environmental variables. Export AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_SESSION_TOKEN variables in your shell then add the following configuration to your knife.rb file:

knife[:aws_access_key_id] = ENV['AWS_ACCESS_KEY_ID']
knife[:aws_secret_access_key] = ENV['AWS_SECRET_ACCESS_KEY']

Additionally if using AWS STS:

knife[:aws_session_token] = ENV['AWS_SESSION_TOKEN']

CLI Arguments

You also have the option of passing your AWS API Key/Secret into the individual knife subcommands using the --aws-access-key-id and --aws-secret-access-key command options

Example of provisioning a new t2.micro Ubuntu 14.04 webserver:

$ knife ec2 server create -r 'role[webserver]' -I ami-cd0fd6be -f t2.micro --aws-access-key-id 'Your AWS Access Key ID' --aws-secret-access-key "Your AWS Secret Access Key"

AWS Credential File

Amazon's newer credential config file format is also supported by knife:

aws_access_key_id = Your AWS Access Key ID
aws_secret_access_key = Your AWS Secret Access Key

In this case, you can point the aws_credential_file option to this file in your knife.rb file, like so:

knife[:aws_credential_file] = "/path/to/credentials/file"

Since the Knife config file is just Ruby you can also avoid hardcoding your home directory, which creates a config that can be used for any user:

knife[:aws_credential_file] = File.join(ENV['HOME'], "/.aws/credentials")

If you have multiple profiles in your credentials file you can define which profile to use. The default profile will be used if not supplied,

knife[:aws_profile] = "personal"

Additional knife.rb Configuration Options

The following configuration options may be set in your knife.rb:

  • flavor
  • image
  • availability_zone
  • ssh_key_name
  • aws_session_token
  • region
  • distro
  • template_file

Using Cloud-Based Secret Data

knife-ec2 now includes the ability to retrieve the encrypted data bag secret and validation keys directly from a cloud-based assets store (currently only S3 is supported). To enable this functionality, you must first upload keys to S3 and give them appropriate permissions. The following is a suggested set of IAM permissions required to make this work:

  "Statement": [
      "Effect": "Allow",
      "Action": [
      "Resource": [

Supported URL format

Use the following configuration options in knife.rb to set the source URLs:

knife[:validation_key_url] = ''
knife[:s3_secret] = ''

Alternatively, URLs can be passed directly on the command line:

  • Validation Key: --validation-key-url s3://chef/my-validator.pem
  • Encrypted Data Bag Secret: --s3-secret s3://chef/encrypted_data_bag_secret

knife-ec2 Subcommands

This plugin provides the following Knife subcommands. Specific command options can be found by invoking the subcommand with a --help flag

knife ec2 server create

Provisions a new server in the Amazon EC2 and then perform a Chef bootstrap (using the SSH or WinRM protocols). The goal of the bootstrap is to get Chef installed on the target system so it can run Chef Client with a Chef Server. The main assumption is a baseline OS installation exists (provided by the provisioning). It is primarily intended for Chef Client systems that talk to a Chef server. The examples below create Linux and Windows instances:

# Create some instances -- knife configuration contains the AWS credentials

# A Linux instance via ssh
knife ec2 server create -I ami-d0f89fb9 --ssh-key your-public-key-id -f m1.medium --ssh-user ubuntu --identity-file ~/.ssh/your-private-key

# A Windows instance via the WinRM protocol -- --ssh-key is still required due to EC2 API operations that need it to grant access to the Windows instance
# `--spot-price` option lets you specify the spot pricing
knife ec2 server create -I ami-173d747e -G windows -f m1.medium --user-data ~/your-user-data-file -x '.\a_local_user' -P 'yourpassword' --ssh-key your-public-key-id --spot-price price-in-USD

# Pass --server-connect-attribute to specify the instance attribute that we will try to connect to via ssh/winrm
# Possible values of --server-connect-attribute: private_dns_name, private_ip_address, public_dns_name, public_ip_address
# If --server-connect-attribute is not specified, knife attempts to determine if connecting to the instance's public or private IP is most appropriate based on other settings
knife ec2 server create -I ami-173d747e -x ubuntu --server-connect-attribute public_ip_address

View additional information on configuring Windows images for bootstrap in the documentation for knife-windows.

Options for bootstrapping Windows

The knife ec2 server create command also supports the following options for bootstrapping a Windows node after the VM s created:

:winrm_password                The WinRM password
:winrm_authentication_protocol Defaults to negotiate, supports kerberos, can be set to basic for debugging
:winrm_transport               Defaults to plaintext, use ssl for improved security
:winrm_port                    Defaults to 5985 plaintext transport, or 5986 for SSL
:ca_trust_file                 The CA certificate file to use to verify the server when using SSL
:winrm_ssl_verify_mode         Defaults to verify_peer, use verify_none to skip validation of the server certificate during testing
:kerberos_keytab_file          The Kerberos keytab file used for authentication
:kerberos_realm                The Kerberos realm used for authentication
:kerberos_service              The Kerberos service used for authentication

knife ec2 server delete

Deletes an existing server in the currently configured AWS account. By default, this does not delete the associated node and client objects from the Chef server. To do so, add the --purge flag

knife ec2 server list

Outputs a list of all servers in the currently configured AWS account. Note, this shows all instances associated with the account, some of which may not be currently managed by the Chef server.

License and Authors

Copyright 2009-2015 Chef Software, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
See the License for the specific language governing permissions and
limitations under the License.
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