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iscsi

Table of Contents

  1. Description
  2. Setup - The basics of getting started with iscsi
  3. Usage - Configuration options and additional functionality
  4. Reference - An under-the-hood peek at what the module is doing and how
  5. Limitations - OS compatibility, etc.
  6. Development - Guide for contributing to the module

Description

Presently this module allows you to manage iSCSI targets using scsi-target-utils and iSCSI initiators using iscsi-initiator-utils. It was first developed against Fedora 21 using Puppet-3.6. It's since been used on Fedora 23 through Fedora 30 and also on CentOS 7.

Using the iscsi::target definition from this module you can quickly provision an iSCSI target on your network. This is useful if you have some storage, be it a file or some block-device that you want to make available over a network. Any iSCSI initiator would connect to this target and at that end you have what appears to be a regular SCSI storage device.

Using the iscsi::initiator definition from this module you can quickly attach to any iSCSI target on your network. Once attached, that target will appear as a local block storage device.

It is not necessary for both the initiator and target to be managed by this module, but that was the development model so other situations may require enhancing this module for the best possible support.

This module will install the necessary packages, manage configuration files, and manage the various services related to initiators and/or targets.

Setup

What iscsi Affects

For iSCSI Initiators

  • Installation of the iscsi-initiator-utils package.
  • Management of iscsid.conf.
  • Management of the iscsid daemon.
  • Target discovery and login.

For iSCSI Targets

  • Installation of the scsi-target-utils package.
  • Management of targets.conf.
  • Management of the tgtd daemon.
  • Optional management of relevant firewall rules.

Setup Requirements

This module, by default, will manage firewall rules using PuppetLab's firewall module (available from the Puppet Module Forge). This functionality can easily be disabled via parameters.

Beginning with iscsi

Provisioning an iSCSI Target

A very simple target setup looks like:

iscsi::target { 'iqn.2015-01.com.example:storage.backups':
    backing   => '/dev/sdb1',
    ipaddress => '192.168.1.123',
    user      => 'backupUser',
    password  => 'SecretSquirrelSauce',
}

This examples uses /dev/sdb1 as the backing-store for the iSCSI target and configures the ACL to only allow an initiator with IP address 192.168.1.123 to connect. Furthermore that initiator must provide the given user name and password for the CHAP initiator authentication.

Provisioning an iSCSI Initiator

This example could be applied on a host with IP address 192.168.1.123 to connect to the example target shown above, assuming it was at IP address 192.168.1.234:

iscsi::initiator { '192.168.1.246':
    user     => 'backupUser',
    password => 'SecretSquirrelSauce',
}

To define a target with CHAP disabled the resource may be defined as follows.

iscsi::initiator { 'production-data'
        enable_chap => false,
        user        => undef,
        password    => undef,
        target      => '192.168.111.4',
}

If you were to look at /proc/partitions before and after applying this, you should see that a new block device appears. You could then use that new device like any other just as if was locally attached.

Usage

Any declaration of an iscsi::target automatically includes the iscsi::target::package and iscsi::target::service classes which are responsible for installing the appropriate package(s), managing the firewall and appropriate service(s) respectively.

Similarly, any declaration of an iscsi::initiator automatically includes iscsi::initiator::package and iscsi::initiator::service which are responsible for installing/managing their appropriate package(s) and service(s).

Reference

Classes:

Defined types:

Data types:

Classes

iscsi::initiator::package class

This class manages the iSCSI initiator package(s) on a host.

ensure

The desired package state. This can be installed (default), absent, or any other value appropriate to the Package resource type.

names

An array of package names needed for the initiator installation. The default should be correct for supported platforms.

iscsi::initiator::service class

This class manages the iSCSI initiator service(s) on a host.

enable

Instance is to be started at boot. Either true (default) or false.

ensure

Instance is to be running (default) or stopped. Alternatively, a Boolean value may also be used with true equivalent to running and false equivalent to stopped.

names

An array of service names needed for the initiator. The default should be correct for supported platforms.

initiator_name

A string containing the initiator name used by the iscsi service. This allows a node to override the default string generated by the iscsi-initiator-utils package. By default this value is undefined.

iscsi::target::package class

This class manages the iSCSI target package(s) on a host.

ensure

The desired package state. This can be installed (default), absent, or any other value appropriate to the Package resource type.

names

An array of package names needed for the target installation. The default should be correct for supported platforms.

iscsi::target::service class

This class manages the iSCSI target service(s) on a host.

enable

Instance is to be started at boot. Either true (default) or false.

ensure

Instance is to be running (default) or stopped. Alternatively, a Boolean value may also be used with true equivalent to running and false equivalent to stopped.

manage_firewall

A Boolean value indicating whether to manage the firewall or not. Defaults to true.

names

An array of service names needed for the target. The default should be correct for supported platforms.

Defined types

iscsi::initiator defined type

This defined type manages an iSCSI initiator using the "send targets" discovery method.

namevar

An arbitrary identifier for the initiator instance unless the target parameter is not set in which case this must provide the value normally set with the target parameter.

enable_chap

This value determines whether CHAP is enabled for initiator authentication. The default value is true. To disable CHAP authentication this value may be set to false.

ensure

Instance is to be present (default) or absent. Alternatively, a Boolean value may also be used with true equivalent to present and false equivalent to absent.

password

The password the target requires for connection authentication. Nodes that do not require authentication must set this parameter to undefined or null via hiera.

port

The TCP port on the target to which is to be connected. Defaults to 3260.

target

Hostname or IP address of the target that is to be connected.

This may be used in place of namevar if it's beneficial to give namevar an arbitrary value.

type

The type of discovery to be used for the target. The default is sendtargets. Some types may be under development or experimental; consult your package documentation for details.

user

The user name the target requires for connection authentication. Nodes that do not require authentication must set this parameter to undefined or null via hiera.

iscsi::target defined type

This defined type manages an iSCSI target.

namevar

An arbitrary identifier for the target instance unless the iqn parameter is not set in which case this must provide the value normally set with the iqn parameter.

backing

The backing file or block device for the LUN instance.

password

The password the initiator must use for authentication to connect.

user

The user name the initiator must use for authentication to connect.

ensure

Instance is to be present (default) or absent. Alternatively, a Boolean value may also be used with true equivalent to present and false equivalent to absent.

ipaddress

Allows connections only from the specified IP address. Defaults to undef, which allows connections from any IP address.

iqn

The iSCSI Qualified Name. See RFC 3720/3721 for more details. Briefly, the fields are:

  • literal string of iqn (iSCSI Qualified Name)
  • date (yyyy-mm) that the naming authority took ownership of the domain
  • reversed domain name of the authority (e.g., com.example)
  • optional : prefixing a storage target name specified by the naming authority

This may be used in place of namevar if it's beneficial to give namevar an arbitrary value.

Data types

Iscsi::Discovery data type

Matches acceptable ensure values for types of iSCSI target discovery: sendtargets, slp, isns, and fw.

Limitations

Tested on Fedora 30 and CentOS 7, but likely to work on any Red Hat variant. See data/common.yaml for the most likely obstructions. If "one size can't fit all", the value should be moved from data/common.yaml to data/os/%{facts.os.name}.yaml instead. See hiera.yaml for how this is handled.

This should be compatible with Puppet 4 and later.

Development

Contributions are welcome via pull requests. All code should generally be compliant with puppet-lint.