IPv6 localhost (::1) missing from /etc/hosts

[ubuntu-server-builder]

This bug was originally filed in Launchpad as LP: #1943798

Launchpad details

affected_projects = []
assignee = None
assignee_name = None
date_closed = 2021-11-02T19:54:20.251837+00:00
date_created = 2021-09-16T07:58:57.593054+00:00
date_fix_committed = 2021-09-16T14:12:59.700569+00:00
date_fix_released = 2021-11-02T19:54:20.251837+00:00
id = 1943798
importance = undecided
is_complete = True
lp_url = https://bugs.launchpad.net/cloud-init/+bug/1943798
milestone = None
owner = rhansen
owner_name = Richard Hansen
private = False
status = fix_released
submitter = rhansen
submitter_name = Richard Hansen
tags = []
duplicates = []

Launchpad user Richard Hansen(rhansen) wrote on 2021-09-16T07:58:57.593054+00:00

/etc/hosts is missing a '::1 localhost' entry:

cloud-init/templates/hosts.debian.tmpl

Line 20 in 023f97d

::1 ip6-localhost ip6-loopback

This causes issues that are discussed in:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=427067
https://bugs.launchpad.net/bugs/301430

Relevant lines in Debian:
https://salsa.debian.org/installer-team/netcfg/-/blob/1767c9264e04652b9150ffc7b25568e4ea6b2bdd/netcfg.h#L42
https://salsa.debian.org/md/netbase/-/blob/9de8afcad482418cc4956dc09bbf6a2e8624d574/debian/netbase.postinst#L8

[ubuntu-server-builder]

Launchpad user Richard Hansen(rhansen) wrote on 2021-09-16T09:23:06.908506+00:00

GitHub pull request: #1021

[ubuntu-server-builder]

Launchpad user James Falcon(falcojr) wrote on 2021-11-02T19:54:21.079823+00:00

This bug is believed to be fixed in cloud-init in version 21.4. If this is still a problem for you, please make a comment and set the state back to New

Thank you.