[train] HostAddressOpt not accepting undercore in the hostnames ( allowed by RFC1033)

[Herve Beraud]

openstack services are failing to start when a hostname with underscord _ is provided

```
2020-08-14 15:42:35.813 8 ERROR nova During handling of the above exception, another exception occurred:
2020-08-14 15:42:35.813 8 ERROR nova
2020-08-14 15:42:35.813 8 ERROR nova Traceback (most recent call last):
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/bin/nova-compute", line 10, in <module>
2020-08-14 15:42:35.813 8 ERROR nova sys.exit(main())
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/nova/cmd/compute.py", line 59, in main
2020-08-14 15:42:35.813 8 ERROR nova service.wait()
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/nova/service.py", line 458, in wait
2020-08-14 15:42:35.813 8 ERROR nova _launcher.wait()
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/oslo_service/service.py", line 392, in wait
2020-08-14 15:42:35.813 8 ERROR nova status, signo = self._wait_for_exit_or_signal()
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/oslo_service/service.py", line 367, in _wait_for_exit_or_signal
2020-08-14 15:42:35.813 8 ERROR nova self.conf.log_opt_values(LOG, logging.DEBUG)
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/oslo_config/cfg.py", line 2589, in log_opt_values
2020-08-14 15:42:35.813 8 ERROR nova _sanitize(opt, getattr(group_attr, opt_name)))
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/oslo_config/cfg.py", line 3134, in __getattr__
2020-08-14 15:42:35.813 8 ERROR nova return self._conf._get(name, self._group)
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/oslo_config/cfg.py", line 2631, in _get
2020-08-14 15:42:35.813 8 ERROR nova value, loc = self._do_get(name, group, namespace)
2020-08-14 15:42:35.813 8 ERROR nova File "/usr/lib/python3.6/site-packages/oslo_config/cfg.py", line 2705, in _do_get
2020-08-14 15:42:35.813 8 ERROR nova raise ConfigFileValueError(message)
2020-08-14 15:42:35.813 8 ERROR nova oslo_config.cfg.ConfigFileValueError: Value for option live_migration_inbound_addr from LocationInfo(location=<Locations.user: (4, True)>, detail='/etc/nova/nova.conf') is not valid: overcloud-novacompute_edge1-0.internalapi.localdomain is not a valid host address
2020-08-14 15:42:35.813 8 ERROR nova

# podman exec -u 0 -ti nova_libvirt rpm -qa | grep oslo-config
python3-oslo-config-6.11.2-0.20200221150642.22c286c.el8ost.noarch

# grep overcloud-novacompute_edge1-0.internalapi.localdomain /etc/hosts
172.16.12.80 overcloud-novacompute_edge1-0.internalapi.localdomain overcloud-novacompute_edge1-0.internalapi

# grep overcloud-novacompute_edge1-0.internalapi.localdomain /etc/hosts
172.16.12.80 overcloud-novacompute_edge1-0.internalapi.localdomain overcloud-novacompute_edge1-0.internalapi
```

# How to reproduce
1. add a hostname with underscord in the config file, for example

/etc/nova/nova.conf
live_migration_inbound_addr = overcloud-novacompute_edge1-0.internalapi.localdomain

ensure hostname is in etc/hosts

2. restart the service

# Details

While a hostname may not contain other characters, such as the underscore character (_), other DNS names may contain the underscore.[1][2][3] This restriction was lifted by RFC 2181. Systems such as DomainKeys and service records use the underscore.

Within the RFC 1033 [3] the following characters are recommended for use in a host name (besides the dot separator):

"A-Z", "a-z", "0-9", dash and underscore

[1] http://domainkeys.sourceforge.net/underscore.html
[2] https://www.ietf.org/rfc/rfc1912.txt
[3] https://www.ietf.org/rfc/rfc1033.txt

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/746723

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/746723
Committed: https://git.openstack.org/cgit/openstack/oslo.config/commit/?id=6480356928c9ae6169ea1e5a5b5f1df3d6e0dc75
Submitter: Zuul
Branch: master

commit 6480356928c9ae6169ea1e5a5b5f1df3d6e0dc75
Author: Hervé Beraud <email address hidden>
Date: Tue Aug 18 15:30:04 2020 +0200

    Add a new type HostDomain.

    HostDomain is like HostAddress with the support of
    _ character - RFC1033

    openstack services are failing to start when a hostname with underscore
    _ is provided.

    Example:

    ```
    overcloud-novacompute_edge1-0.internalapi.localdomain
    overcloud-novacompute_edge1-0.internalapi
    ```

    Nova use `HostAddressOpt` to define `live_migration_inbound_addr`,
    and if a hostname with underscore is present in the config file
    then the service fail to start.

    Example:

    ```
    /etc/nova/nova.conf
    live_migration_inbound_addr =
    overcloud-novacompute_edge1-0.internalapi.localdomain
    ```

    FQDN is a domain name that specifies its exact
    location in the tree hierarchy of the Domain Name System (DNS).

    Underscore are allowed by RFC1033 [1][2][3]. Indeed, while a hostname may not
    contain other characters, such as the underscore character (_), other
    DNS names may contain the underscore.[1][2].
    Systems such as DomainKeys and service records use the underscore.

    These changes allow us to use underscore with the `HostDomain`.

    [1] https://www.ietf.org/rfc/rfc1912.txt
    [2] https://www.ietf.org/rfc/rfc1033.txt
    [3] http://domainkeys.sourceforge.net/underscore.html

    Co-authored-by: Daniel Bengtsson <email address hidden>
    Change-Id: I0a0670207f96a987996d329e5efa9a5eb2ce000c
    Closes-Bug: #1892044

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/victoria
Review: https://review.opendev.org/759411

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/759411
Committed: https://git.openstack.org/cgit/openstack/oslo.config/commit/?id=f37bcc779347c9e0d1e37258a6d072b718edf7f7
Submitter: Zuul
Branch: stable/victoria

commit f37bcc779347c9e0d1e37258a6d072b718edf7f7
Author: Hervé Beraud <email address hidden>
Date: Tue Aug 18 15:30:04 2020 +0200

    Add a new type HostDomain.

    HostDomain is like HostAddress with the support of
    _ character - RFC1033

    openstack services are failing to start when a hostname with underscore
    _ is provided.

    Example:

    ```
    overcloud-novacompute_edge1-0.internalapi.localdomain
    overcloud-novacompute_edge1-0.internalapi
    ```

    Nova use `HostAddressOpt` to define `live_migration_inbound_addr`,
    and if a hostname with underscore is present in the config file
    then the service fail to start.

    Example:

    ```
    /etc/nova/nova.conf
    live_migration_inbound_addr =
    overcloud-novacompute_edge1-0.internalapi.localdomain
    ```

    FQDN is a domain name that specifies its exact
    location in the tree hierarchy of the Domain Name System (DNS).

    Underscore are allowed by RFC1033 [1][2][3]. Indeed, while a hostname may not
    contain other characters, such as the underscore character (_), other
    DNS names may contain the underscore.[1][2].
    Systems such as DomainKeys and service records use the underscore.

    These changes allow us to use underscore with the `HostDomain`.

    [1] https://www.ietf.org/rfc/rfc1912.txt
    [2] https://www.ietf.org/rfc/rfc1033.txt
    [3] http://domainkeys.sourceforge.net/underscore.html

    Co-authored-by: Daniel Bengtsson <email address hidden>
    Change-Id: I0a0670207f96a987996d329e5efa9a5eb2ce000c
    Closes-Bug: #1892044
    (cherry picked from commit 6480356928c9ae6169ea1e5a5b5f1df3d6e0dc75)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/ussuri
Review: https://review.opendev.org/761181

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/761181
Committed: https://git.openstack.org/cgit/openstack/oslo.config/commit/?id=1fcb3e8acd3c229c74c87d80fd183cfc2432bace
Submitter: Zuul
Branch: stable/ussuri

commit 1fcb3e8acd3c229c74c87d80fd183cfc2432bace
Author: Hervé Beraud <email address hidden>
Date: Tue Aug 18 15:30:04 2020 +0200

    Add a new type HostDomain.

    HostDomain is like HostAddress with the support of
    _ character - RFC1033

    openstack services are failing to start when a hostname with underscore
    _ is provided.

    Example:

    ```
    overcloud-novacompute_edge1-0.internalapi.localdomain
    overcloud-novacompute_edge1-0.internalapi
    ```

    Nova use `HostAddressOpt` to define `live_migration_inbound_addr`,
    and if a hostname with underscore is present in the config file
    then the service fail to start.

    Example:

    ```
    /etc/nova/nova.conf
    live_migration_inbound_addr =
    overcloud-novacompute_edge1-0.internalapi.localdomain
    ```

    FQDN is a domain name that specifies its exact
    location in the tree hierarchy of the Domain Name System (DNS).

    Underscore are allowed by RFC1033 [1][2][3]. Indeed, while a hostname may not
    contain other characters, such as the underscore character (_), other
    DNS names may contain the underscore.[1][2].
    Systems such as DomainKeys and service records use the underscore.

    These changes allow us to use underscore with the `HostDomain`.

    [1] https://www.ietf.org/rfc/rfc1912.txt
    [2] https://www.ietf.org/rfc/rfc1033.txt
    [3] http://domainkeys.sourceforge.net/underscore.html

    Co-authored-by: Daniel Bengtsson <email address hidden>
    Change-Id: I0a0670207f96a987996d329e5efa9a5eb2ce000c
    Closes-Bug: #1892044
    (cherry picked from commit 6480356928c9ae6169ea1e5a5b5f1df3d6e0dc75)
    (cherry picked from commit f37bcc779347c9e0d1e37258a6d072b718edf7f7)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/train
Review: https://review.opendev.org/762112

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/762112
Committed: https://git.openstack.org/cgit/openstack/oslo.config/commit/?id=9b1ccea642f0769cb6c49bf814ddab62ca5d8180
Submitter: Zuul
Branch: stable/train

commit 9b1ccea642f0769cb6c49bf814ddab62ca5d8180
Author: Hervé Beraud <email address hidden>
Date: Tue Aug 18 15:30:04 2020 +0200

    Add a new type HostDomain.

    HostDomain is like HostAddress with the support of
    _ character - RFC1033

    openstack services are failing to start when a hostname with underscore
    _ is provided.

    Example:

    ```
    overcloud-novacompute_edge1-0.internalapi.localdomain
    overcloud-novacompute_edge1-0.internalapi
    ```

    Nova use `HostAddressOpt` to define `live_migration_inbound_addr`,
    and if a hostname with underscore is present in the config file
    then the service fail to start.

    Example:

    ```
    /etc/nova/nova.conf
    live_migration_inbound_addr =
    overcloud-novacompute_edge1-0.internalapi.localdomain
    ```

    FQDN is a domain name that specifies its exact
    location in the tree hierarchy of the Domain Name System (DNS).

    Underscore are allowed by RFC1033 [1][2][3]. Indeed, while a hostname may not
    contain other characters, such as the underscore character (_), other
    DNS names may contain the underscore.[1][2].
    Systems such as DomainKeys and service records use the underscore.

    These changes allow us to use underscore with the `HostDomain`.

    [1] https://www.ietf.org/rfc/rfc1912.txt
    [2] https://www.ietf.org/rfc/rfc1033.txt
    [3] http://domainkeys.sourceforge.net/underscore.html

    Co-authored-by: Daniel Bengtsson <email address hidden>
    Change-Id: I0a0670207f96a987996d329e5efa9a5eb2ce000c
    Closes-Bug: #1892044
    (cherry picked from commit 6480356928c9ae6169ea1e5a5b5f1df3d6e0dc75)
    (cherry picked from commit f37bcc779347c9e0d1e37258a6d072b718edf7f7)
    (cherry picked from commit 1fcb3e8acd3c229c74c87d80fd183cfc2432bace)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/oslo.config 8.4.0 release.