Red Hat Training

A Red Hat training course is available for Red Hat Satellite

A.3. Satellite Specific Functions and Variables

This section lists Satellite specific functions and variables for ERB templates. Note that some of them can be used in any kind of template, others are limited, for example job templates accept only @host variables and variables from Table A.4, “Kickstart Specific Variables” are only applicable in Kickstart templates.

You can use the functions listed in the following table across all kinds of templates.

Table A.1. Generic Functions

Name	Description
indent(n)	Indents the block of code by n spaces, useful when using a snippet template that is not indented.
foreman_url(kind)	Returns the full URL to host-rendered templates of the given kind. For example, templates of the "provision" type usually reside at http://HOST/unattended/provision.
snippet(name)	Renders the specified snippet template. Useful for nesting provisioning templates.
snippets(file)	Renders the specified snippet found in the Foreman database, attempts to load it from the `unattended/snippets/` directory if it is not found in the database.
snippet_if_exists(name)	Renders the specified snippet, skips if no snippet with the specified name is found.

Example A.1. Using the snippet and indent Functions

The following syntax imports the subscription_manager_registration snippet to the template and indents it by four spaces:

<%= indent 4 do
snippet 'subscription_manager_registration'
end %>

The following functions can be used in job templates. See Section 12.2.4, “Creating Advanced Templates” for usage examples.

Table A.2. Functions Specific to Job Templates

Name	Description
input(input_name)	Returns the value of the specified input on the job execution.
render_template(name, parameters)	Renders the specified template, similar to the generic snippet() function but enables passing arguments to the template.

The following variables enable using host data within templates.

Table A.3. Host Specific Variables and Functions

Name	Description
@host.architecture	The architecture of the host.
@host.bond_interfaces	Returns an array of all bonded interfaces. See Note.
@host.capabilities	The method of system provisioning, can be either build (for example kickstart) or image.
@host.certname	The SSL certificate name of the host.
@host.diskLayout	The disk layout of the host. Can be inherited from the operating system.
@host.domain	The domain of the host.
@host.environment	The Puppet environment of the host.
@host.facts	Returns a Ruby hash of facts from Facter. For example to access the 'ipaddress' fact from the output, specify @host.facts['ipaddress'].
@host.grub_pass	Returns the host's GRUB password.
@host.hostgroup	The host group of the host.
@host.info['parameters']	Returns a Ruby hash containing information on host parameters. For example, use @host.info['parameters']['lifecycle_environment'] to get the life cycle environment of a host.
@host.image_build?	Returns `true` if the host is provisioned using an image.
@host.interfaces	Contains an array of all available host interfaces including the primary interface. See Note.
@host.interfaces_with_identifier('IDs')	Returns array of interfaces with given identifier. You can pass an array of multiple identifiers as an input, for example @host.interfaces_with_identifier(['eth0', 'eth1']). See Note.
@host.ip	The IP address of the host.
@host.location	The location of the host.
@host.mac	The MAC address of the host.
@host.managed_interfaces	Returns an array of managed interfaces (excluding BMC and bonded interfaces). See Note.
@host.medium	The assigned operating system installation medium.
@host.name	The full name of the host.
@host.operatingsystem.family	The operating system family.
@host.operatingsystem.major	The major version number of the assigned operating system.
@host.operatingsystem.minor	The minor version number of the assigned operating system.
@host.operatingsystem.name	The assigned operating system name.
@host.operatingsystem.boot_files_uri(@host.medium,@host.architecture)	Full path to the kernel and initrd, returns an array.
@host.os.medium_uri(@host)	The URI used for provisioning (path configured in installation media).
@host.param_false?(name)	Returns `false` if host parameter of a given name evaluates to false.
@host.param_true?(name)	Returns `true` if host parameter of a given name evaluates to true.
@host.params['parameter_name']	Returns the value of specified parameters.
@host.primary_interface	Returns the primary interface of the host.
@host.provider	The compute resource provider.
@host.provision_interface	Returns the provisioning interface of the host. Returns an interface object.
@host.ptable	The partition table name.
@host.puppetmaster	The Puppet master the host should use.
@host.pxe_build?	Returns `true` if the host is provisioned using the network or PXE.
@host.shortname	The short name of the host.
@host.sp_ip	The IP address of the BMC interface.
@host.sp_mac	The MAC address of the BMC interface.
@host.sp_name	The name of the BMC interface.
@host.sp_subnet	The subnet of the BMC network.
@host.subnet.dhcp	Returns `true` if a DHCP proxy is configured for this host.
@host.subnet.dns_primary	The primary DNS server of the host.
@host.subnet.dns_secondary	The secondary DNS server of the host.
@host.subnet.gateway	The gateway of the host.
@host.subnet.mask	The subnet mask of the host.
@host.url_for_boot(:initrd)	Full path to the initrd image associated with this host. Not recommended, as it does not interpolate variables.
@host.url_for_boot(:kernel)	Full path to the kernel associated with this host. Not recommended, as it does not interpolate variables, prefer boot_files_uri.
@provisioning_type	Equals to 'host' or 'hostgroup' depending on type of provisioning.
@static	Returns `true` if the network configuration is static.
@template_name	Name of the template being rendered.
grub_pass	Returns the GRUB password wrapped in md5pass argument, that is `--md5pass=#{@host.grub_pass}`.
ks_console	Returns a string assembled using the port and the baud rate of the host which can be added to a kernel line. For example `console=ttyS1,9600`.
root_pass	Returns the root password configured for the system.

Note

Host variables related to network interfaces, such as @host.interfaces or @host.bond_interfaces return interface data grouped in an array. To extract a parameter value of a specific interface, use Ruby methods to parse the array. For example, to get information about the first interface from an array and use it in a kickstart template:

<% myinterface = @host.interfaces.first %>
IPADDR="<%= myinterface.ip %>"
NETMASK="<%= myinterface.subnet.mask %>"
GATEWAY="<%= myinterface.subnet.gateway %>"

You can iterate over the interface array, for example to extract an array of interface names use:

<% ifnames = []
@host.interfaces.each do |i|
  ifnames.push(i.name)
end %>

Example A.2. Using Host Specific Variables

The following example checks if the host has Puppet and the Puppetlabs repository enabled:

<%
pm_set = @host.puppetmaster.empty? ? false : true
puppet_enabled = pm_set || @host.param_true?('force-puppet')
puppetlabs_enabled = @host.param_true?('enable-puppetlabs-repo')
%>

The following example shows how to capture the minor and major version of the host's operating system, which can be used for package related decisions:

<%
os_major = @host.operatingsystem.major.to_i
os_minor = @host.operatingsystem.minor.to_i
%>

<% if ((os_minor < 2) && (os_major < 14)) -%>
...
<% end -%>

The following example imports the 'kickstart_networking_setup' snippet if the host's subnet has the DHCP boot mode enabled:

<% subnet = @host.subnet %>
<% if subnet.respond_to?(:dhcp_boot_mode?) -%>
<%= snippet 'kickstart_networking_setup' %>
<% end -%>

The majority of common Ruby methods can be applied on host specific variables. For example, to extract the last segment of the host's IP address, you can use:

<% @host.ip.split('.').last %>

The following variables are designed to be used within kickstart provisioning templates.

Table A.4. Kickstart Specific Variables

Name	Description
@arch	The host architecture name, same as @host.architecture.name.
@dynamic	Returns `true` if the partition table being used is a %pre script (has the #Dynamic option as the first line of the table).
@epel	A command which will automatically install the correct version of the epel-release rpm. Use in a %post script.
@mediapath	The full kickstart line to provide the URL command.
@osver	The operating system major version number, same as @host.operatingsystem.major.

Select Your Language

Infrastructure and Management

Cloud Computing

Storage

Runtimes

Integration and Automation

Red Hat Training

A.3. Satellite Specific Functions and Variables