RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.
Bug 1760072 - cloudinit/net/sysconfig.py write incorrect config for dhcp-stateless openstack subnets
Summary: cloudinit/net/sysconfig.py write incorrect config for dhcp-stateless openstac...
Keywords:
Status: CLOSED CURRENTRELEASE
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: cloud-init
Version: 7.9
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Eduardo Otubo
QA Contact: xiachen
URL:
Whiteboard:
Depends On:
Blocks: 1459187 1760394
TreeView+ depends on / blocked
 
Reported: 2019-10-09 18:49 UTC by Harald Jensås
Modified: 2024-11-20 07:54 UTC (History)
9 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
: 1760394 (view as bug list)
Environment:
Last Closed: 2020-05-13 11:43:32 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Launchpad 1847517 0 None None None 2019-10-09 18:49:24 UTC

Description Harald Jensås 2019-10-09 18:49:24 UTC 
Description of problem:


Version-Release number of selected component (if applicable):


How reproducible:


Steps to Reproduce:
1. Install openstack
2. Create a subnet with:
ipv6_address_mode -c ipv6_ra_mode
+-------------------+------------------+
| Field | Value |
+-------------------+------------------+
| ipv6_address_mode | dhcpv6-stateless |
| ipv6_ra_mode | dhcpv6-stateless |
+-------------------+------------------+
3. Deploy an instance

Actual results:
File: openstack/latest/network_data.json
----------------------------------------
{
    "services": [
        {
            "type": "dns",
            "address": "fd12:3456:789a:1::1"
        }
    ],
    "networks": [
        {
            "network_id": "cf79eea0-6196-45a0-b9f8-ff9dd95eaab3",
            "type": "ipv6_dhcpv6-stateless",
            "services": [
                {
                    "type": "dns",
                    "address": "fd12:3456:789a:1::1"
                }
            ],
            "netmask": "ffff:ffff:ffff:ffff::",
            "link": "tap5910c6cc-2d",
            "routes": [
                {
                    "netmask": "::",
                    "network": "::",
                    "gateway": "fd12:3456:789a:1::fffe"
                }
            ],
            "ip_address": "fd12:3456:789a:1:f816:3eff:fee2:3aa3",
            "id": "network0"
        }
    ],
    "links": [
        {
            "vif_id": "5910c6cc-2d6e-4a44-bf05-2accdefd0316",
            "type": "phy",
            "ethernet_mac_address": "fa:16:3e:73:0d:96",
            "id": "tap5910c6cc-2d",
            "mtu": 1450
        }
    ]
}

The network config forces the client to try dhcpv6, not stateless e.g slaac. This fails when there is no DHCPv6 configured, or DHCPv6 is only configured to provide advanced options such a bootfile-url etc.

# Created by cloud-init on instance boot automatically, do not edit.
#
BOOTPROTO=none
DEFROUTE=yes
DEVICE=eth0
DHCPV6C=yes
HWADDR=fa:16:3e:73:0d:96
IPV6INIT=yes
IPV6_DEFAULTGW=fd12:3456:789a:1::fffe
MTU=1450
ONBOOT=yes
TYPE=Ethernet
USERCTL=no

Expected results:
The configuration written should differentiate between dhcp6-stateful and dhcp6-stateless.
For dhcp6-stateless "DHCPV6C=yes" should be replaced by IPV6_AUTOCONF=yes as shown in the example below.

# Created by cloud-init on instance boot automatically, do not edit.
#
BOOTPROTO=none
DEFROUTE=yes
DEVICE=eth0
IPV6_AUTOCONF=yes
HWADDR=fa:16:3e:73:0d:96
IPV6INIT=yes
IPV6_DEFAULTGW=fd12:3456:789a:1::fffe
MTU=1450
ONBOOT=yes
TYPE=Ethernet
USERCTL=no

Additional info:

The issue starts is in the following code[1]:
    if 'dhcp' in network['type']:
        t = 'dhcp6' if network['type'].startswith('ipv6') else 'dhcp4'
        subnet.update({
            'type': t,
        })

This makes the assumption that 'ipv6_dhcpv6-stateless' and 'ipv6_dhcpv6-stateful' can be treated the same.

Then in the code[2] the subnet type is checked and DHCPV6C is always used.
    if subnet_type == 'dhcp6':
        # TODO need to set BOOTPROTO to dhcp6 on SUSE
        iface_cfg['IPV6INIT'] = True
        iface_cfg['DHCPV6C'] = True

Grepping the source code it looks like this is only affecting cloudinit/net/sysconfig.py.

[1] https://git.launchpad.net/cloud-init/tree/cloudinit/sources/helpers/openstack.py#n587
[2] https://git.launchpad.net/cloud-init/tree/cloudinit/net/sysconfig.py#n346
Comment 2 Harald Jensås 2019-10-09 18:52:23 UTC 
Description of problem:
cloud-init writed incorrect configuration for dhcp6-stateless subnets.

Version-Release number of selected component (if applicable):
cloud-init-18.5-3.el7.centos.x86_64

How reproducible:
100%
Comment 3 Harald Jensås 2019-10-09 21:54:08 UTC 
Proposed fix: https://git.launchpad.net/~harald-jensas/cloud-init/commit/?id=d707d885ac5a2b5dccf491693de718613cbd2240

I will test this change, if it works I will propose it for merge upstream.
Comment 4 Harald Jensås 2019-10-10 03:08:34 UTC 
The fix tested and works.

Upstream merge request: https://code.launchpad.net/~harald-jensas/cloud-init/+git/cloud-init/+merge/373932


(undercloud) [centos@undercloud ~]$ openstack subnet show ctlplane-subnet
+-------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field             | Value                                                                                                                                                   |
+-------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------+
| allocation_pools  | fd12:3456:789a:1::4-fd12:3456:789a:1::aaa9,fd12:3456:789a:1::b000-fd12:3456:789a:1::fffd,fd12:3456:789a:1::ffff-fd12:3456:789a:1:ffff:ffff:ffff:fffe    |
| cidr              | fd12:3456:789a:1::/64                                                                                                                                   |
| created_at        | 2019-10-09T23:57:12Z                                                                                                                                    |
| description       |                                                                                                                                                         |
| dns_nameservers   | fd12:3456:789a:1::1                                                                                                                                     |
| enable_dhcp       | True                                                                                                                                                    |
| gateway_ip        | fd12:3456:789a:1::fffe                                                                                                                                  |
| host_routes       |                                                                                                                                                         |
| id                | 968c4fd0-6cec-48f8-9e7f-d1d0c479fcd2                                                                                                                    |
| ip_version        | 6                                                                                                                                                       |
| ipv6_address_mode | dhcpv6-stateless                                                                                                                                        |
| ipv6_ra_mode      | dhcpv6-stateless                                                                                                                                        |
| location          | cloud='', project.domain_id=, project.domain_name='Default', project.id='9c8878b90225463e980c7d3425527e78', project.name='admin', region_name='', zone= |
| name              | ctlplane-subnet                                                                                                                                         |
| network_id        | c73d4b39-1e4f-4a48-a1d7-4d91da3f5cd9                                                                                                                    |
| prefix_length     | None                                                                                                                                                    |
| project_id        | 9c8878b90225463e980c7d3425527e78                                                                                                                        |
| revision_number   | 0                                                                                                                                                       |
| segment_id        | c37882bc-2169-411d-9825-86e673c677a2                                                                                                                    |
| service_types     |                                                                                                                                                         |
| subnetpool_id     | None                                                                                                                                                    |
| tags              |                                                                                                                                                         |
| updated_at        | 2019-10-09T23:57:12Z                                                                                                                                    |
+-------------------+---------------------------------------------------------------------------------------------------------------------------------------------------------+
(undercloud) [centos@undercloud ~]$ openstack server list
+--------------------------------------+------------------------+--------+-----------------------------------------------+----------------+---------+
| ID                                   | Name                   | Status | Networks                                      | Image          | Flavor  |
+--------------------------------------+------------------------+--------+-----------------------------------------------+----------------+---------+
| 5cc2be01-8da5-47f8-8322-ed043fb13640 | overcloud-controller-0 | ACTIVE | ctlplane=fd12:3456:789a:1:f816:3eff:fe7d:50f0 | overcloud-full | control |
+--------------------------------------+------------------------+--------+-----------------------------------------------+----------------+---------+
(undercloud) [centos@undercloud ~]$ ping6 fd12:3456:789a:1:f816:3eff:fe7d:50f0
PING fd12:3456:789a:1:f816:3eff:fe7d:50f0(fd12:3456:789a:1:f816:3eff:fe7d:50f0) 56 data bytes
64 bytes from fd12:3456:789a:1:f816:3eff:fe7d:50f0: icmp_seq=1 ttl=64 time=0.974 ms
Comment 7 Harald Jensås 2019-11-20 18:03:17 UTC 
Upstream commit to fix this merged: https://github.com/canonical/cloud-init/commit/62bbc262c3c7f633eac1d09ec78c055eef05166a
Note You need to log in before you can comment on or make changes to this bug.