On Tue, Apr 7, 2026 at 4:59 AM wlswo <[email protected]> wrote:
> When the python unbound library is not installed, dns_resolve.resolve()
> returns None for hostnames, causing all hostname-based TCP connections
> to silently fail. This affects services like neutron-ovn-metadata-agent
> that use hostname-based connection strings (e.g. tcp:hostname:6642).
>
> Add a fallback to socket.getaddrinfo() which uses the system resolver
> (/etc/hosts, nsswitch.conf, system DNS) when unbound is unavailable
> or fails to resolve.
>
> Signed-off-by: wlswo <[email protected]>
>
> Signed-off-by: wlswo <[email protected]>
> ---
> python/ovs/socket_util.py | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/python/ovs/socket_util.py b/python/ovs/socket_util.py
> index a26298b75..93764568b 100644
> --- a/python/ovs/socket_util.py
> +++ b/python/ovs/socket_util.py
> @@ -235,6 +235,17 @@ def _inet_parse_active(target, default_port):
> host_name = str(ipaddress.ip_address(host_name))
> except ValueError:
> host_name = dns_resolve.resolve(host_name)
+ if not host_name:
>
resolve() returns None in the case that the dns resolution returned no
results. If we want support for system dns lookup, it should probably just
be added to dns_resolve.py.
-M
> + # Fallback to the system resolver (e.g. /etc/hosts, system
> DNS)
> + # when the unbound library is not available.
> + try:
> + result = socket.getaddrinfo(
> + ":".join(address[0:-1]).lstrip('[').rstrip(']'),
> + None, 0, socket.SOCK_STREAM)
> + if result:
> + host_name = result[0][4][0]
> + except socket.gaierror:
> + pass
> if not host_name:
> raise ValueError("%s: bad peer name format" % target)
> return (host_name, port)
> --
> 2.40.1
>
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>
>
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