CentOS 7.8 host with the following kernel command line, (ipv6 disabled due to local DNS providing ipv6 records when wider network doesn't support ipv6, leading to excessive timeouts on connections to dual-stack hosts):
[stack@undercloud-controller ~]$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.10.0-1127.18.2.el7.x86_64 root=/dev/mapper/centos_undercloud--controller-root ro crashkernel=auto rd.lvm.lv=centos_undercloud-controller/root rd.lvm.lv=centos_undercloud-controller/swap nomodeset ipv6.disable=1 net.ifnames=0 console=ttyS0,115200n1 LANG=en_GB.UTF-8
running "openstack undercloud install --verbose --debug" fails, these entries seem pertinent.
(successes have been elided for brevity)
From:
TASK [tripleo-kernel : Set extra sysctl options] *********************************************************
Thursday 20 August 2020 15:59:41 +0100 (0:00:00.525) 0:01:17.416 *******
failed: [undercloud-controller] (item={u'opt': {u'value': 0}, u'key': u'net.ipv6.conf.default.disable_ipv6'}) => {"ansible_loop_var": "item", "changed": false, "item": {"key": "net.ipv6.conf.default.disable_ipv6", "opt": {"value": 0}}, "msg": "setting net.ipv6.conf.default.disable_ipv6 failed: sysctl: cannot stat /proc/sys/net/ipv6/conf/default/disable_ipv6: N
o such file or directory\n"}
failed: [undercloud-controller] (item={u'opt': {u'value': 0}, u'key': u'net.ipv6.conf.all.disable_ipv6'}) => {"ansible_loop_var": "item", "changed": false, "item": {"key": "net.ipv6.conf.all.disable_ipv6", "opt": {"value": 0}}, "msg": "setting net.ipv6.conf.all.disable_ipv6 failed: sysctl: cannot stat /proc/sys/net/ipv6/conf/all/disable_ipv6: No such file or d
irectory\n"}
failed: [undercloud-controller] (item={u'opt': {u'value': 1}, u'key': u'net.ipv6.ip_nonlocal_bind'}) => {"ansible_loop_var": "item", "changed": false, "item": {"key": "net.ipv6.ip_nonlocal_bind", "opt": {"value": 1}}, "msg": "setting net.ipv6.ip_nonlocal_bind failed: sysctl: cannot stat /proc/sys/net/ipv6/ip_nonlocal_bind: No such file or directory\n"}
failed: [undercloud-controller] (item={u'opt': {u'value': 0}, u'key': u'net.ipv6.conf.lo.disable_ipv6'}) => {"ansible_loop_var": "item", "changed": false, "item": {"key": "net.ipv6.conf.lo.disable_ipv6", "opt": {"value": 0}}, "msg": "setting net.ipv6.conf.lo.disable_ipv6 failed: sysctl: cannot stat /proc/sys/net/ipv6/conf/lo/disable_ipv6: No such file or direc
tory\n"}
NO MORE HOSTS LEFT *************************************************************************************************
booting with ipv6.disable=0 allows the task "tripleo-kernel : Set extra sysctl options" to complete.
(changed output with ipv6.disable=0, non ipv6 changes removed)
TASK [tripleo-kernel : Set extra sysctl options] *************************************************************************************************
Thursday 20 August 2020 16:38:00 +0100 (0:00:00.525) 0:01:00.508 *******
changed: [undercloud-controller] => (item={u'opt': {u'value': 0}, u'key': u'net.ipv6.conf.default.disable_ipv6'})
changed: [undercloud-controller] => (item={u'opt': {u'value': 0}, u'key': u'net.ipv6.conf.all.disable_ipv6'})
changed: [undercloud-controller] => (item={u'opt': {u'value': 1}, u'key': u'net.ipv6.ip_nonlocal_bind'})
changed: [undercloud-controller] => (item={u'opt': {u'value': 0}, u'key': u'net.ipv6.conf.lo.disable_ipv6'})
NO MORE HOSTS LEFT *************************************************************************************************
If ansible is trying to disable ipv6, it shouldn't fail if ipv6 wasn't active in the first place.
