Provided by: chef_11.8.2-2_all 
NAME
knife-exec - The man page for the knife exec subcommand.
The knife exec subcommand uses the Knife configuration file to execute Ruby scripts in the context of a
fully configured chef-client. This subcommand is most often used to run scripts that will only access
server one time (or otherwise very infrequently). Use this subcommand any time that an operation does not
warrant full usage of the Knife subcommand library.
For Ruby scripts that will be run using the exec subcommand, note the following:
• The Ruby script must be located on the system from which Knife is run (and not be located on any of
the systems that Knife will be managing).
• Shell commands will be run from a management workstation. For example, something like %x[ls -lash
/opt/only-on-a-node] would give you the directory listing for the "opt/only-on-a-node" directory or
a "No such file or directory" error if the file does not already exist locally.
• When the chef-shell DSL is available, the chef-client DSL will not be (unless the management
workstation is also a chef-client). Without the chef-client DSL, a bash block cannot be used to run
bash commands.
Common Options
The following options can be run with all Knife sub-commands and plug-ins:
-c CONFIG, --config CONFIG
The configuration file to use.
--color
Indicates that colored output will be used.
-d, --disable-editing
Indicates that $EDITOR will not be opened; data will be accepted as-is.
--defaults
Indicates that Knife will use the default value, instead of asking a user to provide one.
-e EDITOR, --editor EDITOR
The $EDITOR that is used for all interactive commands.
-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.
-f FILE_NAME, --file FILE_NAME
Indicates that the private key will be saved to a specified file name.
-F FORMAT, --format FORMAT
The output format: summary (default), text, json, yaml, and pp.
-h, --help
Shows help for the command.
-k KEY, --key KEY
The private key that Knife will use to sign requests made by the API client to the server.
--no-color
Indicates that color will not be used in the output.
-p PASSWORD, --password PASSWORD
The user password.
--print-after
Indicates that data will be shown after a destructive operation.
-s URL, --server-url URL
The URL for the server.
-u USER, --user USER
The user name used by Knife to sign requests made by the API client to the server. Authentication
will fail if the user name does not match the private key.
-v, --version
The version of the chef-client.
-V, --verbose
Set for more verbose outputs. Use -VV for maximum verbosity.
-y, --yes
Indicates that the response to all confirmation prompts will be "Yes" (and that Knife will not ask
for confirmation).
Authenticated API Requests
The knife exec subcommand can be used to make authenticated API requests to the server using the
following methods:
┌───────────┬───────────────────────────────────────┐
│Method │ Description │
├───────────┼───────────────────────────────────────┤
│api.delete │ Use to delete an object from the │
│ │ server. │
├───────────┼───────────────────────────────────────┤
│api.get │ Use to get the details of an object │
│ │ on the server. │
├───────────┼───────────────────────────────────────┤
│api.post │ Use to add an object to the server. │
├───────────┼───────────────────────────────────────┤
│api.put │ Use to update an object on the │
│ │ server. │
└───────────┴───────────────────────────────────────┘
These methods are used with the -E option, which executes that string locally on the workstation using
chef-shell. These methods have the following syntax:
$ knife exec -E 'api.method(/endpoint)'
where:
• api.method is the corresponding authentication method --- api.delete, api.get, api.post, or api.put
• /endpoint is an endpoint in the Chef Server API
For example, to get the data for a node named "Example_Node":
$ knife exec -E 'puts api.get("/nodes/Example_Node")'
and to ensure that the output is visible in the console, add the puts in front of the API authorization
request:
$ knife exec -E 'puts api.get("/nodes/Example_Node")'
where puts is the shorter version of the $stdout.puts predefined variable in Ruby.
The following example shows how to add a client named "IBM305RAMAC" and the /clients endpoint, and then
return the private key for that user in the console:
$ client_desc = {
"name" => "IBM305RAMAC",
"admin" => false
}
new_client = api.post("/clients", client_desc)
puts new_client["private_key"]
Syntax
This argument has the following syntax:
$ knife exec SCRIPT (options)
Options
This subcommand has the following options:
-E CODE, --exec CODE
A string of code that will be executed.
-p PATH:PATH, --script-path PATH:PATH
A colon-separated path at which Ruby scripts are located.
Examples
There are three ways to use knife exec to run Ruby script files. For example:
$ knife exec /path/to/script_file
Or:
$ knife exec -E 'RUBY CODE'
Or:
$ knife exec
RUBY CODE
^D
To check the status of Knife using a Ruby script named "status.rb" (which looks like):
printf "%-5s %-12s %-8s %s\n", "Check In", "Name", "Ruby", "Recipes"
nodes.all do |n|
checkin = Time.at(n['ohai_time']).strftime("%F %R")
rubyver = n['languages']['ruby']['version']
recipes = n.run_list.expand(_default).recipes.join(", ")
printf "%-20s %-12s %-8s %s\n", checkin, n.name, rubyver, recipes
end
and is located in a directory named "scripts", enter:
$ knife exec scripts/status.rb
To show the available free memory for all nodes, enter:
$ knife exec -E 'nodes.all {|n| puts "#{n.name} has #{n.memory.total} free memory"}'
To list all of the available search indexes, enter:
$ knife exec -E 'puts api.get("search").keys'
To query a node for multiple attributes using a Ruby script named search_attributes.rb (which looks
like):
% cat scripts/search_attributes.rb
query = ARGV[2]
attributes = ARGV[3].split(",")
puts "Your query: #{query}"
puts "Your attributes: #{attributes.join(" ")}"
results = {}
search(:node, query) do |n|
results[n.name] = {}
attributes.each {|a| results[n.name][a] = n[a]}
end
puts results
exit 0
enter:
% knife exec scripts/search_attributes.rb "hostname:test_system" ipaddress,fqdn
to return something like:
Your query: hostname:test_system
Your attributes: ipaddress fqdn
{"test_system.example.com"=>{"ipaddress"=>"10.1.1.200", "fqdn"=>"test_system.example.com"}}
AUTHOR
Opscode
Chef 11.8.0 KNIFE-EXEC(1)