(Maybe) Multiple Network Rendering Bugs

[bin456789]

These are my subjective judgments. They might bugs, or not. Not tested.
Developers can close this thread at any time.

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1

cloud-init/cloudinit/net/network_state.py

Line 406 in d7eb828

if subnet.get("type").endswith("6") or is_ipv6_address(

If this line also applies to network config v1. The v1 types ipv6_dhcpv6-stateful, ipv6_dhcpv6-stateless, and ipv6_slaac results false here

Obviously, it is handled well here:

cloud-init/cloudinit/net/__init__.py

Line 1301 in d7eb828

if subnet["type"].endswith("6") or subnet["type"] in IPV6_DYNAMIC_TYPES:

2

As far as I know, in the Subnet type of network configuration, dhcp6 is equivalent to ipv6_dhcpv6-stateful.
However, in the following places, dhcp6 and ipv6_dhcpv6-stateful are treated differently, resulting in different outcomes:

cloud-init/cloudinit/net/network_manager.py

Lines 137 to 146 in d7eb828

	method_map = {
	"static": "manual",
	"static6": "manual",
	"dhcp6": "auto",
	"ipv6_slaac": "auto",
	"ipv6_dhcpv6-stateless": "auto",
	"ipv6_dhcpv6-stateful": "dhcp",
	"dhcp4": "auto",
	"dhcp": "auto",
	}

cloud-init/cloudinit/net/network_manager.py

Lines 167 to 171 in d7eb828

	if subnet_type in [
	"ipv6_dhcpv6-stateful",
	"ipv6_dhcpv6-stateless",
	"ipv6_slaac",
	]:

cloud-init/cloudinit/net/networkd.py

Line 211 in d7eb828

elif t == "dhcp6":

cloud-init/cloudinit/net/sysconfig.py

Line 439 in d7eb828

subnet_type == "ipv6_dhcpv6-stateful"

The last one I previously reported #4615
There might be similar issues elsewhere.

3

cloud-init/cloudinit/net/eni.py

Lines 577 to 581 in d7eb828

	if (
	subnet["type"] == "dhcp4"
	or subnet["type"] == "dhcp6"
	or subnet["type"] == "ipv6_dhcpv6-stateful"
	):

Similar issues. dhcp is equivalent to dhcp4.
Should add dhcp here

4

cloud-init/cloudinit/net/sysconfig.py

Lines 1119 to 1121 in d7eb828

	if network_state.use_ipv6:
	netcfg.append("NETWORKING_IPV6=yes")
	netcfg.append("IPV6_AUTOCONF=no")

IPV6_AUTOCONF=no is set here. It should be enabled by default.

[bin456789]

FWIW to the issue 2.

the dhcp6/ipv6_dhcpv6-stateful words in cloud-init v1 config seems to differ from the dhcp6 definition in netplan.

In netplan, dhcp6 can include ipv6_slaac.

If you are in an IPv6-only environment with completely stateless auto-configuration (SLAAC with RDNSS), this option can be set to cause the interface to be brought up. (Setting accept-ra alone is not sufficient.) Auto-configuration will still honour the contents of the router advertisement and only use DHCP if requested in the RA.
https://netplan.readthedocs.io/en/stable/netplan-yaml/

It's unclear whether dhcp6 in cloud-init v2 config follows the Netplan documentation. As Cloud-init's document not clearly states that.

If it is, the _v2_to_v1_ipcfg method can't determine the word dhcp6 whether the user intends ipv6_slaac or ipv6_dhcpv6-stateful.

cloud-init/cloudinit/net/network_state.py

Line 883 in d7eb828

def _v2_to_v1_ipcfg(self, cfg):