erase_devices_iterations controls the number of random passes, not total passes

[Mathieu Mitchell]

Currently, the [deploy] erase_devices_iterations configuration setting controls the number of random passes shred runs on the device.

Ironic reads the setting from the config, and pushes it to IPA:
https://github.com/openstack/ironic/blob/4482eaa59b3ad4f92d7097231100260a487215f4/ironic/drivers/modules/deploy_utils.py#L638
Ironic defaults to one unless provided in the configuration file:
https://github.com/openstack/ironic/blob/4482eaa59b3ad4f92d7097231100260a487215f4/ironic/drivers/modules/deploy_utils.py#L69

IPA reads it and defaults to "1":
https://github.com/openstack/ironic-python-agent/blob/a630a921d3ec3ec8af84a756247d92b6910c2110/ironic_python_agent/hardware.py#L621

However, invoking shred on the command line reveals the following:
ubuntu@ubuntu:~$ shred --force --zero --verbose --iterations 1 my_block_device
shred: my_block_device: pass 1/2 (random)...
shred: my_block_device: pass 2/2 (000000)...

Running shred with --iterations 0 is probably was was intended, aka only one pass and only zeroes:
ubuntu@ubuntu:~$ shred --force --zero --verbose --iterations 0 my_block_device
shred: my_block_device: pass 1/1 (000000)...

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/304101
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=c47c6d2ab54f88a054c9e1566c02c219bd1a79c0
Submitter: Jenkins
Branch: master

commit c47c6d2ab54f88a054c9e1566c02c219bd1a79c0
Author: Mathieu Mitchell <email address hidden>
Date: Mon Apr 11 08:27:08 2016 -0400

    Allow configuring shred's final overwrite with zeros

    Introduce shred_final_overwrite_with_zeros, a new configuration option
    to control whether devices will receive a final overwrite with zeros
    during cleaning. Additionally, rename erase_devices_iterations to
    shred_random_overwrite_iterations to clarify the true meaning of this
    configuration option.

    Also, ensure a warning is raised in the logs to raise awareness around
    the potential security risk of running cleaning with iterations=0 and
    overwrite_with_zeros=False.

    Change-Id: I0dd3f488ab2cd0df778f34a5a23948fa0c6c4334
    Closes-Bug: #1568811
    Depends-On: I7053034f5b5bc6737b535ee601e6fb71284d4a83

[Thierry Carrez (ttx)]

This issue was fixed in the openstack/ironic 6.0.0 release.