[RFE] Switching to local boot by default

[Dmitry Tantsur]

There are quite a few reasons to use local boot:
1. Nodes can safely reboot while ctlplane is down (important for installers like TripleO)
2. Tenants have control over kernel arguments (might be seen as downside as well)
3. Multitenant networks is not supported with netboot.

We probably don't want to get rid of netboot completely, because some boot-from-volume cases depend on it. However, we should eventually have local boot by default.

Here is the plan:

1. Introduce a new option default_boot_option ("netboot" by default) setting the default boot option when one is not set on a node.
2. Issue a deprecation warning that we are going to change its default, asking operators to set an explicit value to this option.
3. After an appropriate deprecation period, flip the default to "local" and leave it there.

[Jim Rollenhagen (jim-rollenhagen)]

I'm good with this, will bug people to see if we can get one more person and approve it.

[Jay Faulkner (jason-oldos)]

I agree this is a good idea, and implementation seems simple enough.

[Ruby Loo (rloo)]

This makes sense. I was trying to think of what this might mean (if anything) in the new world with driver composition reform. As long as we don't have to deal with different BootInterfaces wanting different defaults for this :), I'm good.

Am going to approve it.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/375458

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/375458
Committed: https://git.openstack.org/cgit/openstack/ironic/commit/?id=93f947c852409af2c56a499428b09ff69ab345a1
Submitter: Jenkins
Branch: master

commit 93f947c852409af2c56a499428b09ff69ab345a1
Author: Dmitry Tantsur <email address hidden>
Date: Fri Sep 23 14:52:16 2016 +0200

    Introduce default_boot_option configuration option

    This is the first step to changing the default boot option from netboot to local.
    The new configuration allows setting the default boot option globally.

    A warning is issued if no explicit value is provided for this configuration.

    Change-Id: I3bd4a165fa2ec1105f34bf5a2150da99136ba4a6
    Partial-Bug: #1619339

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/446961

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/446961
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=625db6e42c6fd33907d8f0164c3ef2c2b609d399
Submitter: Jenkins
Branch: master

commit 625db6e42c6fd33907d8f0164c3ef2c2b609d399
Author: Dmitry Tantsur <email address hidden>
Date: Fri Mar 17 12:28:27 2017 +0100

    [ironic] expose default boot_option in configuration and change it to local

    Ironic is going to change the default boot_option from netboot to local in the
    near future. Let's be pro-active, and change it in advance. Users cano change
    it back via new IronicDefaultBootOption configuration.

    Partial-Bug: #1619339
    Change-Id: Idddc2e384c6cd9a1595777090500bf04f230edd4

[Emilien Macchi (emilienm)]

There are no currently open reviews on this bug, changing the status back to the previous state and unassigning. If there are active reviews related to this bug, please include links in comments.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/504335

[Ruby Loo (rloo)]

patch to change [deploy]/default_boot_option to local: https://review.openstack.org/#/c/492114

It is now Rocky, let's do it!

[OpenStack Infra (hudson-openstack)]

Change abandoned by Shivanand Tendulker (<email address hidden>) on branch: master
Review: https://review.openstack.org/504335
Reason: We will use https://review.openstack.org/#/c/492114 for this change.