* kubeadm: do not ignore preflight errors blindly

The "ignoring all errors" seems to date back to the inception of the
kubeadm support (it was --skip-preflight-check before).

This can mask real errors and prevent users from seeing them.

Do not ignore any errors by default and make the set of ignored errors
configurable.

* download/kubeadm: remove redundant task

The mode is already set by the previous `copy` task.

* Validate kubeadm configs

This should help to fail early when we have invalid kubeadm configs (from
a kubespray bug or a misconfiguration).

* kubeadm-upgrade: remove unnecessary bool cast

* Convert kubeadm join discovery timeout to v1beta4 config

* CI: Ignore kubeadm:Mem errors on some setup.

Currently there is not much difference between the files, if there are more changes in the future,
please use different files to distinguish them (you can use the kubeadm_config_api_version variable)

Signed-off-by: ChengHao Yang <17496418+tico88612@users.noreply.github.com>

Testing for group membership with group names makes Kubespray more
tolerant towards the structure of the inventory.
Where 'inventory_hostname in groups["some_group"] would fail if
"some_group" is not defined, '"some_group" in group_names' would not.

We explicitly check for equality so customizing kubeadm_version does not
work at the moment.

Use only one variable instead.

Consistent boolean values in ansible playbooks

Signed-off-by: Bas Meijer <bas.meijer@enexis.nl>

This reverts commit 4b0a134b.

The mentionned PR break scale.yml. This goes back to the status quo
until a proper fix can be provided, at which point we'll reapply the
PR.

This should avoid permissions problems when the user creating the
directory and the user creating the content are different (when
containers images are saved by root for instances, because the user
can't use the container runtime).

* Refactor of kubeadm images listing

Instead of setting multiples facts, we directly create the dict we need from
kubeadm output.

* Remove useless 'default' filters in roles/download

* Only download kubeadm images where needed

This reverts commit c6e5314f.

There is no user of the download mirrors support in kubespray, for a
long time.

* Fix download retry when get_url has no status_code.

* Fix until clause in download role.

* Decouple role kubespray-defaults from download

Avoids doing re-importing the download role on every invocation of
kubespray-defaults (and skipping everything).

This has a measurable effect on playbook performance.

* Update docs refering to moved download defaults

Signed-off-by: Kay Yan <kay.yan@daocloud.io>

Signed-off-by: Boris Barnier <bozzo@users.noreply.github.com>