Fix scaling (#5889)

* etcd: etcd-events doesn't depend on etcd_cluster_setup

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* etcd: remove condition already present on include_tasks

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* etcd: fix scaling up

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* etcd: use *access_addresses, do not delegate to etcd[0]

We want to wait for the full cluster to be healthy,
so use all the cluster addresses
Also we should be able to run the playbook when etcd[0] is down
(not tested), so do not delegate to etcd[0]

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* etcd: use failed_when for health check

unhealthy cluster is expected on first run, so use failed_when
instead of ignore_errors to remove scary red messages

Also use run_once

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* kubernetes/preinstall: ensure ansible_fqdn is up to date after changing /etc/hosts

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>

* kubernetes/master: regenerate apiserver cert if needed

Signed-off-by: Etienne Champetier <champetier.etienne@gmail.com>