knife bootstrap

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A node is any physical, virtual, or cloud machine that is configured to be maintained by a chef-client. In order to bootstrap a node, you will first need a working installation of the Chef software package. A bootstrap is a process that installs the chef-client on a target system so that it can run as a chef-client and communicate with a Chef server. There are two ways to do this:

Use the knife bootstrap subcommand to run a bootstrap operation that installs the chef-client on the target system. The bootstrap operation must specify the IP address or FQDN of the target system.

Considerations:

  • As of Chef 12.8 you can create a .chef/client.d directory on your workstation and the contents of that client.d directory will be copied to the system being bootstrapped by the knife bootstrap command. You can also set the client_d_dir option in config.rb to point to an arbitrary directory instead of .chef/client.d, and the contents of that directory will be copied to the system being bootstrapped. All config files inside client.d directory get copied into /etc/chef/client.d on the system being bootstrapped.
  • Starting with Chef 12.0, use the knife ssl fetch command to pull down the SSL certificates from the on-premises Chef server and add them to the /trusted_certs_dir on the workstation. These certificates are used during a knife bootstrap operation.
  • To bootstrap the Chef Client on Microsoft Windows machines, the knife-windows plugin is required.

Syntax

This subcommand has the following syntax:

$ knife bootstrap FQDN_or_IP_ADDRESS (options)

Options

Note

Review the list of common options available to this (and all) knife subcommands and plugins.

This subcommand has the following options:

-A, --forward-agent
Enable SSH agent forwarding.
--bootstrap-curl-options OPTIONS
Arbitrary options to be added to the bootstrap command when using cURL. This option may not be used in the same command with --bootstrap-install-command.
--bootstrap-install-command COMMAND
Execute a custom installation command sequence for the chef-client. This option may not be used in the same command with --bootstrap-curl-options or --bootstrap-wget-options.
--bootstrap-no-proxy NO_PROXY_URL_or_IP

A URL or IP address that specifies a location that should not be proxied.

Note

This option is used internally by Chef to help verify bootstrap operations during testing and should never be used during an actual bootstrap operation.

--bootstrap-preinstall-command COMMANDS
Custom commands to run before installing chef-client
--bootstrap-proxy-pass PROXY_PASS
The proxy authentication password for the node being bootstrapped
--bootstrap-proxy-user PROXY_USER
The proxy authentication username for the node being bootstrapped
--bootstrap-proxy PROXY_URL
The proxy server for the node that is the target of a bootstrap operation.
--bootstrap-vault-file VAULT_FILE
The path to a JSON file that contains a list of vaults and items to be updated.
--bootstrap-vault-item VAULT_ITEM
A single vault and item to update as vault:item.
--bootstrap-vault-json VAULT_JSON

A JSON string that contains a list of vaults and items to be updated.

For example:

--bootstrap-vault-json '{ "vault1": ["item1", "item2"], "vault2": "item2" }'
--bootstrap-version VERSION
The version of the chef-client to install.
--bootstrap-wget-options OPTIONS
Arbitrary options to be added to the bootstrap command when using GNU Wget. This option may not be used in the same command with --bootstrap-install-command.
-E ENVIRONMENT, --environment ENVIRONMENT
The name of the environment. When this option is added to a command, the command will run only against the named environment.
-G GATEWAY, --ssh-gateway GATEWAY
The SSH tunnel or gateway that is used to run a bootstrap action on a machine that is not accessible from the workstation.
--hint HINT_NAME[=HINT_FILE]

An Ohai hint to be set on the target node.

Ohai hints are used to tell Ohai something about the system that it is running on that it would not be able to discover itself. An Ohai hint exists if a JSON file exists in the hint directory with the same name as the hint. For example, calling hint?('antarctica') in an Ohai plugin would return an empty hash if the file antarctica.json existed in the hints directory, and return nil if the file does not exist.

If the hint file contains JSON content, it will be returned as a hash from the call to hint?.

{
  "snow": true,
  "penguins": "many"
}

antarctica_hint = hint?('antarctica')
if antarctica_hint['snow']
  "There are #{antarctica_hint['penguins']} penguins here."
else
  'There is no snow here, and penguins like snow.'
end

Hint files are located in the /etc/chef/ohai/hints/ directory by default. Use the Ohai.config[:hints_path] setting in the client.rb file to customize this location.

HINT_FILE is the name of the JSON file. HINT_NAME is the name of a hint in a JSON file. Use multiple --hint options to specify multiple hints.

-i IDENTITY_FILE, --ssh-identity-file IDENTITY_FILE
The SSH identity file used for authentication. Key-based authentication is recommended.
-j JSON_ATTRIBS, --json-attributes JSON_ATTRIBS
A JSON string that is added to the first run of a chef-client.
--json-attribute-file FILE
A JSON file to be added to the first run of chef-client.
-N NAME, --node-name NAME

The name of the node.

Note

This option is required for a validatorless bootstrap.

--[no-]fips
Allows OpenSSL to enforce FIPS-validated security during the chef-client run.
--[no-]host-key-verify
Use --no-host-key-verify to disable host key verification. Default setting: --host-key-verify.
--[no-]node-verify-api-cert
Verify the SSL certificate on the Chef server. When true, the chef-client always verifies the SSL certificate. When false, the chef-client uses the value of ssl_verify_mode to determine if the SSL certificate requires verification. If this option is not specified, the setting for verify_api_cert in the configuration file is applied.
--node-ssl-verify-mode MODE

Set the verify mode for HTTPS requests. Options: none or peer.

Use none to do no validation of SSL certificates.

Use peer to do validation of all SSL certificates, including the Chef server connections, S3 connections, and any HTTPS remote_file resource URLs used in the chef-client run. This is the recommended setting.

-p PORT, --ssh-port PORT
The SSH port.
-P PASSWORD, --ssh-password PASSWORD
The SSH password. This can be used to pass the password directly on the command line. If this option is not specified (and a password is required) knife prompts for the password.
--prerelease
Install pre-release gems.
-r RUN_LIST, --run-list RUN_LIST
A comma-separated list of roles and/or recipes to be applied.
--secret SECRET
The encryption key that is used for values contained within a data bag item.
--secret-file FILE
The path to the file that contains the encryption key.
--sudo
Execute a bootstrap operation with sudo.
--sudo-preserve-home
Use to preserve the non-root user’s HOME environment.
-t TEMPLATE, --bootstrap-template TEMPLATE
The bootstrap template to use. This may be the name of a bootstrap template—chef-full, for example—or it may be the full path to an Embedded Ruby (ERB) template that defines a custom bootstrap. Default value: chef-full, which installs the chef-client using the Chef installer on all supported platforms.
--use-sudo-password
Perform a bootstrap operation with sudo; specify the password with the -P (or --ssh-password) option.
-V -V
Run the initial chef-client run at the debug log-level (e.g. chef-client -l debug).
-V -V -V
Run the initial chef-client run at the trace log-level (e.g. chef-client -l trace). This was added in Chef Client 14.
-x USERNAME, --ssh-user USERNAME
The SSH user name.

Note

See config.rb for more information about how to add certain knife options as settings in the config.rb file.

Validatorless Bootstrap

The ORGANIZATION-validator.pem is typically added to the .chef directory on the workstation. When a node is bootstrapped from that workstation, the ORGANIZATION-validator.pem is used to authenticate the newly-created node to the Chef server during the initial chef-client run. Starting with Chef client 12.1, it is possible to bootstrap a node using the USER.pem file instead of the ORGANIZATION-validator.pem file. This is known as a “validatorless bootstrap”.

To create a node via the USER.pem file, simply delete the ORGANIZATION-validator.pem file on the workstation. For example:

$ rm -f /home/lamont/.chef/myorg-validator.pem

and then make the following changes in the config.rb file:

  • Remove the validation_client_name setting
  • Edit the validation_key setting to be something that isn’t a path to an existent ORGANIZATION-validator.pem file. For example: /nonexist.

As long as a USER.pem is also present on the workstation from which the validatorless bootstrap operation will be initiated, the bootstrap operation will run and will use the USER.pem file instead of the ORGANIZATION-validator.pem file.

When running a validatorless knife bootstrap operation, the output is similar to:

desktop% knife bootstrap 10.1.1.1 -N foo01.acme.org \
  -E dev -r 'role[base]' -j '{ "foo": "bar" }' \
  --ssh-user vagrant --sudo
Node foo01.acme.org exists, overwrite it? (Y/N)
Client foo01.acme.org exists, overwrite it? (Y/N)
Creating new client for foo01.acme.org
Creating new node for foo01.acme.org
Connecting to 10.1.1.1
10.1.1.1 Starting first Chef Client run...
[....etc...]

knife bootstrap Options

Use the following options with a validatorless bootstrap to specify items that are stored in“chef-vault“:

--bootstrap-vault-file VAULT_FILE
The path to a JSON file that contains a list of vaults and items to be updated.
--bootstrap-vault-item VAULT_ITEM
A single vault and item to update as vault:item.
--bootstrap-vault-json VAULT_JSON

A JSON string that contains a list of vaults and items to be updated.

For example:

--bootstrap-vault-json '{ "vault1": ["item1", "item2"], "vault2": "item2" }'

Note

The --node-name option is required for a validatorless bootstrap (Changed in Chef Client 12.4).

FIPS Mode

Federal Information Processing Standards (FIPS) is a United States government computer security standard that specifies security requirements for cryptography. The current version of the standard is FIPS 140-2. The chef-client can be configured to allow OpenSSL to enforce FIPS-validated security during a chef-client run. This will disable cryptography that is explicitly disallowed in FIPS-validated software, including certain ciphers and hashing algorithms. Any attempt to use any disallowed cryptography will cause the chef-client to throw an exception during a chef-client run.

Note

Chef uses MD5 hashes to uniquely identify files that are stored on the Chef server. MD5 is used only to generate a unique hash identifier and is not used for any cryptographic purpose.

Notes about FIPS:

  • May be enabled for nodes running on Microsoft Windows and Enterprise Linux platforms
  • Should only be enabled for environments that require FIPS 140-2 compliance
  • May not be enabled for any version of the chef-client earlier than 12.8

Bootstrap a node using FIPS

$ knife bootstrap 192.0.2.0 -P vanilla -x root -r 'recipe[apt],recipe[xfs],recipe[vim]' --fips

which shows something similar to:

OpenSSL FIPS 140 mode enabled
...
192.0.2.0 Chef Client finished, 12/12 resources updated in 78.942455583 seconds

Custom Templates

The default chef-full template uses the Chef installer. For most bootstrap operations, regardless of the platform on which the target node is running, using the chef-full distribution is the best approach for installing the chef-client on a target node. In some situations, a custom template may be required.

For example, the default bootstrap operation relies on an Internet connection to get the distribution to the target node. If a target node cannot access the Internet, then a custom template can be used to define a specific location for the distribution so that the target node may access it during the bootstrap operation. The example below will show you how to create a bootstrap template that uses a custom artifact store for Chef packages and installation scripts, as well as a RubyGem mirror:

  1. A custom bootstrap template file must be located in a bootstrap/ directory, which is typically located within the ~/.chef/ directory on the local workstation. Navigate to the .chef directory, and create a bootstrap directory within it:

    mkdir bootstrap

  2. Move to the bootstrap directory and create a blank template file; this example will use template.erb for the template name:

    touch template.erb

  3. Still in the bootstrap directory, issue the following command to copy the chef-full configuration to your new template:

    find /opt/chefdk/embedded/lib/ruby -type f -name chef-full.erb -exec cat {} \; > template.erb

    This command searches for the chef-full template file under /opt/chefdk/embedded/lib/ruby, and then outputs the contents of the file to template.erb. If you used a different template file name, be sure to replace template.erb with the template file you created during the last step.

  4. Update template.erb to replace omnitruck.chef.io with the URL of an install.sh script on your artifact store:

    install_sh="<%= knife_config[:bootstrap_url] ? knife_config[:bootstrap_url] : "http://packages.example.com/install.sh" %>"

  5. Still in your text editor, locate the following line near the bottom of your template.erb file:

    cat > /etc/chef/client.rb <<'EOP'
<%= config_content %>
EOP

    Beneath it, add the following, replacing gems.example.com with the URL of your gem mirror:

    cat >> /etc/chef/client.rb <<'EOP'
rubygems_url "http://gems.example.com"
EOP

    This appends the appropriate rubygems_url setting to the /etc/chef/client.rb file that is created during bootstrap, which ensures that your nodes use your internal gem mirror.

Bootstrap a Custom Template

You can use the --bootstrap-template option with the knife bootstrap subcommand to specify the name of your bootstrap template file:

$ knife bootstrap 123.456.7.8 -x username -P password --sudo --bootstrap-template "template"

Alternatively, you can use the knife[:bootstrap_template] option within config.rb to specify the template that knife bootstrap will use by default when bootstrapping a node. It should point to your custom template within the bootstrap directory:

knife[:bootstrap_template] = "#{current_dir}/bootstrap/template.erb"

Examples

The following examples show how to use this knife subcommand:

Bootstrap a node

$ knife bootstrap 192.0.2.0 -P vanilla -x root -r 'recipe[apt],recipe[xfs],recipe[vim]'

which shows something similar to:

...
192.0.2.0 Chef Client finished, 12/12 resources updated in 78.942455583 seconds

Use knife node show to verify:

$ knife node show debian-wheezy.int.domain.org

which returns something similar to:

Node Name:   debian-wheezy.int.domain.org
Environment: _default
FQDN:        debian-wheezy.int.domain.org
IP:          192.0.2.0
Run List:    recipe[apt], recipe[xfs], recipe[vim]
Roles:
Recipes:     apt, xfs, vim, apt::default, xfs::default, vim::default
Platform:    debian 7.4
Tags:

Use an SSH password

$ knife bootstrap 192.0.2.0 -x username -P PASSWORD --sudo

Use a file that contains a private key

$ knife bootstrap 192.0.2.0 -x username -i ~/.ssh/id_rsa --sudo

Specify options when using cURL

$ knife bootstrap --bootstrap-curl-options "--proxy http://myproxy.com:8080"

Specify options when using GNU Wget

$ knife bootstrap --bootstrap-wget-options "-e use_proxy=yes -e http://myproxy.com:8080"

Specify a custom installation command sequence

$ knife bootstrap --bootstrap-install-command "curl -l http://mycustomserver.com/custom_install_chef_script.sh | sudo bash -s --"