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Chef knife plug-in for AWS EC2
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Knife EC2

Gem Version Build Status

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


We highly recommend using ChefDK, which includes knife-ec2 out of the box. If for some reason you can't use ChefDK you can manually install the gem.

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. The knife-ec2 plugin supports multiple methods for configuring these credentials including:

  • AWS configuration / credential files (preferred method)
  • knife.rb / config.rb configuration files
  • environmental variables
  • command line arguments

AWS Configuration / Credential Files

The preferred method of storing credentials for AWS is to use Amazon's own credential and configuration files. The files allow for multiple "profiles", each with their own set of credentials. Also since these credentials aren't stored in your knife.rb/config.rb files you don't have to worry about accidentally checking credentials into a git repository. The configs can be created by hand or generated automatically by running aws configure if the AWS Command Line Interface (awscli) is installed.

See Amazon's Configuration and Credentials Files documentation for additional information on the file format and default locations for Linux/Mac & Windows hosts.

Alternative Config Files Location

If you're not storing the files in their default directory you'll need to specify the location in your knife.rb/config.rb files:

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

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

knife[:aws_credential_file] = File.join(ENV['HOME'], "/.aws/credentials")
knife[:aws_config_file] = File.join(ENV['HOME'], "/path/to/configuration/file")

Specifying the AWS Profile

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"

Config.rb / Knife.rb Configuration

If you prefer to keep all of your configuration in a single location with Chef you can store your Amazon EC2 credentials in Chef's knife.rb or config.rb files:

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 or config.rb files will be checked into a source control management system, or are 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 16.04 webserver:

$ knife ec2 server create -r 'role[webserver]' -I ami-5e8bb23b -f t2.micro --aws-access-key-id 'Your AWS Access Key ID' --aws-secret-access-key "Your AWS Secret Access Key" -ssh-key my_key_name --region us-west-2

Note: Passing credentials via the command line exposes the credentials in your shell's history and should be avoided unless absolutely necessary.

Additional config.rb & knife.rb Configuration Options

The following configuration options may be set in your configuration file:

  • flavor
  • image
  • availability_zone
  • ssh_key_name
  • aws_session_token
  • region

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 or config.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, 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.

Adding server_id to the node name

Users can also include the ec2 server id in the node name by placing %s in the string passed to the --chef-node-name option. The %s is replaced by the ec2 server id dynamically. e.g. -N "www-server-%s" or --chef-node-name "www-server-%s"

Tagging node in Chef

Users can use option --tag-node-in-chef for tagging node in EC2 and chef both with knife ec2 server create command. If user does not pass this option, then the node will be tagged only in EC2.

Tagging EBS Volumes

Users can attach ebs volumes to a new instance being created with knife-ec2 using --volume-tags Tag=Value[,Tag=Value...].

Bootstrap Windows (2012 R2 and above platform) instance without user-data through winrm ssl transport

Users can bootstrap the Windows instance without the need to provide the user-data. knife-ec2 has the ability to bootstrap the Windows instance through winrm protocol using the ssl transport. This requires users to set --winrm-transport option as ssl and --winrm-ssl-verify-mode option as verify_none. This will do the necessary winrm ssl transport configurations on the target node and the bootstrap will just work.

Note: Users also need to pass the --security-group-ids option with IDs of the security group(s) having the required ports opened like 5986 for winrm ssl transport. In case if --security-group-ids option is not passed then make sure that the default security group in your account has the required ports opened.

Below is the sample command to create a Windows instance and bootstrap it through ssl transport without passing any user-data:

knife ec2 server create -N chef-node-name -I your-windows-image -f flavor-of-server -x '.\a_local_user' -P 'yourpassword' --ssh-key your-public-key-id --winrm-transport ssl --winrm-ssl-verify-mode verify_none --security-group-ids your-security-groups -VV

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 ami list

This command provides the feature to list all EC2 AMIs. It also provides the feature to filter the AMIs based on owner and platform.

knife ec2 ami list

Options for AMIs list

  • Owner: By default owner is aws-marketplace but you can specify following owner with the help of -o or --owner:

    command: knife ec2 ami list -o (options)

    :self                         Displays the list of AMIs created by the user.
    :aws-marketplace              Displays all AMIs form trusted vendors like Ubuntu, Microsoft, SAP, Zend as well as many open source offering.
    :micosoft                     Displays only Microsoft vendor AMIs.
  • Platform: By default all platform AMIs are displayed, but you can filter your response by specifying the platform using -p or --platform:

    command: knife ec2 ami list -p (options)

    :Allowed platform             windows, ubuntu, debian, centos, fedora, rhel, nginx, turnkey, jumpbox, coreos, cisco, amazon, nessus
  • Search: User can search any string into the description column by using -s or --search:

    command: knife ec2 ami list -s (search_keyword)

    :search_keyword             Any String or number

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.

knife ec2 flavor list

Outputs a list of all instance types comprising varying combinations of CPU, memory, storage, and architecture capacity of the currently configured AWS account. Note, this shows all instances type associated with the account.

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

Development Documentation

All documentation is written using YARD. You can generate a by running:

rake docs


For information on contributing to this project please see our Contributing Documentation

License & Copyright

  • Copyright:: Copyright (c) 2009-2018 Chef Software, Inc.
  • License:: Apache License, Version 2.0
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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