Use the user resource to add users, update existing users, remove users, and to lock/unlock user passwords.
Note
System attributes are collected by Ohai at the start of every chef-client run. By design, the actions available to the user resource are processed after the start of the chef-client run. This means that system attributes added or modified by the user resource during the chef-client run must be reloaded before they can be available to the chef-client. These system attributes can be reloaded in two ways: by picking up the values at the start of the (next) chef-client run or by using the ohai resource to reload the system attributes during the current chef-client run.
A user resource block manages users on a node:
user 'a user' do comment 'A random user' uid '1234' gid '1234' home '/home/random' shell '/bin/bash' password '$1$JJsvHslasdfjVEroftprNn4JHtDi' end
The full syntax for all of the properties that are available to the user resource is:
user 'name' do comment String force TrueClass, FalseClass # see description gid String, Integer home String iterations Integer manage_home TrueClass, FalseClass non_unique TrueClass, FalseClass notifies # see description password String provider Chef::Provider::User salt String shell String subscribes # see description system TrueClass, FalseClass uid String, Integer username String # defaults to 'name' if not specified action Symbol # defaults to :create if not specified end
where
user
is the resourcename
is the name of the resource block:action
identifies the steps the chef-client will take to bring the node into the desired statecomment
, force
, gid
, home
, iterations
, manage_home
, non_unique
, password
, provider
, salt
, shell
, system
, uid
, and username
are properties of this resource, with the Ruby type shown. See “Properties” section below for more information about all of the properties that may be used with this resource.This resource has the following actions:
:create
:lock
:manage
:modify
:nothing
:remove
:unlock
This resource has the following properties:
comment
Ruby Type: String
One (or more) comments about the user.
force
Ruby Types: TrueClass, FalseClass
Force the removal of a user. May be used only with the :remove
action.
Warning
Using this property may leave the system in an inconsistent state. For example, a user account will be removed even if the user is logged in. A user’s home directory will be removed, even if that directory is shared by multiple users.
gid
Ruby Types: String, Integer
The identifier for the group.
group
Ruby Types: String, Integer
The group
property is an alias of the gid
property.
home
Ruby Type: String
The location of the home directory.
ignore_failure
Ruby Types: TrueClass, FalseClass
Continue running a recipe if a resource fails for any reason. Default value: false
.
iterations
Ruby Type: Integer
Mac OS X platform only, 10.8 (or higher). The number of iterations for a password with a SALTED-SHA512-PBKDF2 shadow hash.
manage_home
Ruby Types: TrueClass, FalseClass
Manage a user’s home directory.
With the :create
action, a user’s home directory is created based on HOME_DIR
. If the home directory is missing, it is created unless CREATE_HOME
in /etc/login.defs
is set to no
. When created, a skeleton set of files and sub-directories is also created in the home directory.
With the :modify
action, a user’s home directory is moved to HOME_DIR
. If the home directory is missing, it is created unless CREATE_HOME
in /etc/login.defs
is set to no
. The contents of the user’s home directory are moved to the new location.
non_unique
Ruby Types: TrueClass, FalseClass
Create a duplicate (non-unique) user account.
notifies
Ruby Type: Symbol, ‘Chef::Resource[String]’
A resource may notify another resource to take action when its state changes. Specify a 'resource[name]'
, the :action
that resource should take, and then the :timer
for that action. A resource may notifiy more than one resource; use a notifies
statement for each resource to be notified.
A timer specifies the point during the chef-client run at which a notification is run. The following timers are available:
:before
:delayed
:immediate
, :immediately
The syntax for notifies
is:
notifies :action, 'resource[name]', :timer
password
Ruby Type: String
The password shadow hash. This property requires that ruby-shadow
be installed. This is part of the Debian package: libshadow-ruby1.8
.
provider
Ruby Type: Chef Class
Optional. Explicitly specifies a provider. See “Providers” section below for more information.
retries
Ruby Type: Integer
The number of times to catch exceptions and retry the resource. Default value: 0
.
retry_delay
Ruby Type: Integer
The retry delay (in seconds). Default value: 2
.
salt
Ruby Type: String
Mac OS X platform only, 10.7 or higher. The salt value for a password shadow hash. Mac OS X version 10.7 uses SALTED-SHA512 and version 10.8 (and higher) uses SALTED-SHA512-PBKDF2 to calculate password shadow hashes.
shell
Ruby Type: String
The login shell.
subscribes
Ruby Type: Symbol, ‘Chef::Resource[String]’
A resource may listen to another resource, and then take action if the state of the resource being listened to changes. Specify a 'resource[name]'
, the :action
to be taken, and then the :timer
for that action.
A timer specifies the point during the chef-client run at which a notification is run. The following timers are available:
:before
:delayed
:immediate
, :immediately
The syntax for subscribes
is:
subscribes :action, 'resource[name]', :timer
system
Ruby Types: TrueClass, FalseClass
Create a system user. This property may be used with useradd
as the provider to create a system user which passes the -r
flag to useradd
.
uid
Ruby Types: String, Integer
The numeric user identifier.
username
Ruby Type: String
The name of the user. Default value: the name
of the resource block See “Syntax” section above for more information.
The supports
attribute of the user
resource has been deprecated. The supports[:manage_home]
property was an alias for the manage_home
property, while the supports[:non_unique]
property was an alias for the non_unique
property.
There are a number of encryption options and tools that can be used to create a password shadow hash. In general, using a strong encryption method like SHA-512 and the passwd
command in the OpenSSL toolkit is a good approach, however the encryption options and tools that are available may be different from one distribution to another. The following examples show how the command line can be used to create a password shadow hash. When using the passwd
command in the OpenSSL tool:
openssl passwd -1 "theplaintextpassword"
When using mkpasswd
:
mkpasswd -m sha-512
For more information:
mkpasswd
package is required and on Ubuntu 10.10+ the whois
package is required.Where a resource represents a piece of the system (and its desired state), a provider defines the steps that are needed to bring that piece of the system from its current state into the desired state.
The chef-client will determine the correct provider based on configuration data collected by Ohai at the start of the chef-client run. This configuration data is then mapped to a platform and an associated list of providers.
Generally, it’s best to let the chef-client choose the provider, and this is (by far) the most common approach. However, in some cases, specifying a provider may be desirable. There are two approaches:
yum_package "foo" do
instead of package "foo" do
, script "foo" do
instead of bash "foo" do
, and so on—when availableprovider
property within the resource block to specify the long name of the provider as a property of a resource. For example: provider Chef::Provider::Long::Name
This resource has the following providers:
Chef::Provider::User::Useradd
, user
Chef::Provider::User::Pw
, user
Chef::Provider::User::Dscl
, user
Chef::Provider::User::Windows
, user
The following examples demonstrate various approaches for using resources in recipes. If you want to see examples of how Chef uses resources in recipes, take a closer look at the cookbooks that Chef authors and maintains: https://github.com/chef-cookbooks.
Create a user named “random”
user 'random' do manage_home true comment 'User Random' uid '1234' gid '1234' home '/home/random' shell '/bin/bash' password '$1$JJsvHslV$szsCjVEroftprNn4JHtDi' end
Create a system user
user 'systemguy' do comment 'system guy' system true shell '/bin/false' end
Create a system user with a variable
The following example shows how to create a system user. In this instance, the home
value is calculated and stored in a variable called user_home
which sets the user’s home
attribute.
user_home = "/home/#{node['cookbook_name']['user']}" user node['cookbook_name']['user'] do gid node['cookbook_name']['group'] shell '/bin/bash' home user_home system true action :create end
Use SALTED-SHA512 passwords
Mac OS X 10.7 calculates the password shadow hash using SALTED-SHA512. The length of the shadow hash value is 68 bytes, the salt value is the first 4 bytes, with the remaining 64 being the shadow hash itself. The following code will calculate password shadow hashes for Mac OS X 10.7:
password = 'my_awesome_password' salt = OpenSSL::Random.random_bytes(4) encoded_password = OpenSSL::Digest::SHA512.hexdigest(salt + password) shadow_hash = salt.unpack('H*').first + encoded_password
Use the calculated password shadow hash with the user resource:
user 'my_awesome_user' do password 'c9b3bd....d843' # Length: 136 end
Use SALTED-SHA512-PBKDF2 passwords
Mac OS X 10.8 (and higher) calculates the password shadow hash using SALTED-SHA512-PBKDF2. The length of the shadow hash value is 128 bytes, the salt value is 32 bytes, and an integer specifies the number of iterations. The following code will calculate password shadow hashes for Mac OS X 10.8 (and higher):
password = 'my_awesome_password' salt = OpenSSL::Random.random_bytes(32) iterations = 25000 # Any value above 20k should be fine. shadow_hash = OpenSSL::PKCS5::pbkdf2_hmac( password, salt, iterations, 128, OpenSSL::Digest::SHA512.new ).unpack('H*').first salt_value = salt.unpack('H*').first
Use the calculated password shadow hash with the user resource:
user 'my_awesome_user' do password 'cbd1a....fc843' # Length: 256 salt 'bd1a....fc83' # Length: 64 iterations 25000 end
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https://docs-archive.chef.io/release/12-13/resource_user.html