* kubedns & kubedns-autoscaler: Stick to master nodes.

 - Tolerate only master nodes and not any NoSchedule taint
 - Pods are on different nodes
 - Pods are required to be on a master node.

* kubedns: use soft nodeAffinity.

Prefer to be on a master node, don't require.

* coredns: Stick to (different) master nodes.

     - Pods are on different nodes
     - Pods are preferred to be on a master node.

Update all configs to current upstream state.
Add more resources (unable to pass tests now)...

Use helm install or support in future

Upstream Changes:

-   weave 2.4.0 (https://github.com/weaveworks/weave/releases/tag/v2.4.0)
-   Support `externalTrafficPolicy: Local` (https://github.com/weaveworks/weave/issues/2924)
-   Make the ipset list size bigger (https://github.com/weaveworks/weave/pull/3305)
-   Break out of kube rm-peers loop if nothing changes (https://github.com/weaveworks/weave/pull/3317)

Our Changes:

-   Revamp weave-net.yml.j2 with upstream changes
-   Add more variables for customization
-   Replace WEAVE_PASSWORD with k8s secret
-   Remove hard-corded seed mode support, in favor of variables customization

Upstream Changes:

-   ingress-nginx 0.17.1 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.17.1)
-   Remove duplicated `securityContext` (https://github.com/kubernetes/ingress-nginx/pull/2705)
-   Remove --publish-service flag, in favor of DaemonSet + hostPort

Close #2998
Close #2999

Upstream Changes:

-   cert-manager 0.4.0 (https://github.com/jetstack/cert-manager/releases/tag/v0.4.0)

According to cluster/binary.yml vault binary will be placed to `{{ bin_dir }}` and according to `inventory/sample/group_vars/all.yml` that is 
`inventory/sample/group_vars/all.yml`

Even without this PR, the operation works well.
However, it is better to use a single slash rather than
a double slash in the path.

This fixes #3014

apiserver cert should be created only once

ingress-nginx 0.16.2 (https://github.com/kubernetes/ingress-nginx/releases/tag/nginx-0.16.2)

This patch simplify ingress-nginx deployment by default deploy on
master, with customizable options; on the other hand, remove the
additional Ansible group "kube-ingress" and its k8s node label
injection.

Reference to https://kubernetes.io/docs/concepts/services-networking/ingress/#prerequisites:

    GCE/Google Kubernetes Engine deploys an ingress controller on the master.

By changing `ingress_nginx_nodeselector` plus custom k8s node
label, user could customize the DaemonSet deployment target.

If `ingress_nginx_nodeselector` is empty, will deploy DaemonSet on
every k8s node.

Upstream Changes:

-   cert-manager 0.3.2 (https://github.com/jetstack/cert-manager/releases/tag/v0.3.2)

Our Changes:

-   Remove legacy addon dir, manifests and namespace before upgrade

Fix failure when the container attribute is not set for a download

The referenced issue (https://github.com/kubernetes/kubeadm/issues/441) has already been fixed.

Upstream Changes:

-   Update CEPH_VERSION to mimic (https://github.com/kubernetes-incubator/external-storage/pull/841)

Our Changes:

-   Using image from official repo which contain latest changes (https://quay.io/repository/external_storage/cephfs-provisioner)

* Add tags for cert serial tasks

This will help facilitate tag-based deployment of specific components.

* fixup kubernetes node

-   cephfs-provisioner 06fddbe2 (https://github.com/kubernetes-incubator/external-storage/tree/06fddbe2/ceph/cephfs)

Noteable changes from upstream:

-   Added storage class parameters to specify a root path within the backing cephfs and, optionally, use deterministic directory and user names (https://github.com/kubernetes-incubator/external-storage/pull/696)
-   Support capacity (https://github.com/kubernetes-incubator/external-storage/pull/770)
-   Enable metrics server (https://github.com/kubernetes-incubator/external-storage/pull/797)

Other noteable changes:

-   Clean up legacy manifests file naming
-   Remove legacy manifests, namespace and storageclass before upgrade
-   `cephfs_provisioner_monitors` simplified as string
-   Default to new deterministic naming
-   Add `reclaimPolicy` support in StorageClass

With legacy non-deterministic naming style (where $UUID are generated ramdonly):

-   cephfs_provisioner_claim_root: /volumes/kubernetes
-   cephfs_provisioner_deterministic_names: false
-   Generated CephFS volume: /volumes/kubernetes/kubernetes-dynamic-pvc-$UUID
-   Generated CephFS user: kubernetes-dynamic-user-$UUID

With new default deterministic naming style (where $NAMESPACE and $PVC are predictable):

-   cephfs_provisioner_claim_root: /volumes
-   cephfs_provisioner_deterministic_names: true
-   Generated CephFS volume: /volumes/$NAMESPACE/$PVC
-   Generated CephFS user: k8s.$NAMESPACE.$PVC

See: e40368ae

* Fixup vault etcd

* Update main.yml