Make dnsmasq daemon set optional

Change additional dnsmasq opts:
- Adjust caching size and TTL
- Disable resolve conf to not create loops
- Change dnsPolicy to default (similarly to kubedns's dnsmasq). The
  ClusterFirst should not be used to not create loops
- Disable negative NXDOMAIN replies to be cached
- Make its very installation as optional step (enabled by default).
  If you don't want more than 3 DNS servers, including 1 for K8s, disable
  it.
- Add docs and a drawing to clarify DNS setup.
- Fix stdout logs for dnsmasq/kubedns app configs
- Add missed notifies to resolvconf -u handler
- Fix idempotency of resolvconf head file changes

Signed-off-by: Bogdan Dobrelya <bdobrelia@mirantis.com>

roles/kubernetes/node/defaults/main.yml

@@ -8,13 +8,6 @@ kube_resolv_conf: "/etc/resolv.conf"
 
 kube_proxy_mode: iptables
 
-# IP address of the DNS server.
-# Kubernetes will create a pod with several containers, serving as the DNS
-# server and expose it under this IP address. The IP address must be from
-# the range specified as kube_service_addresses. This magic will actually
-# pick the 10th ip address in the kube_service_addresses range and use that.
-dns_server: "{{ kube_service_addresses|ipaddr('net')|ipaddr(253)|ipaddr('address') }}"
-
 # kube_api_runtime_config:
 #   - extensions/v1beta1/daemonsets=true
 #   - extensions/v1beta1/deployments=true

roles/kubernetes/node/templates/kubelet.j2

@@ -19,7 +19,9 @@ KUBELET_HOSTNAME="--hostname-override={{ inventory_hostname }}"
 KUBELET_REGISTER_NODE="--register-node=false"
 {% endif %}
 # location of the api-server
-{% if dns_setup %}
+{% if dns_setup|bool and skip_dnsmasq|bool %}
+KUBELET_ARGS="--cluster_dns={{ skydns_server }} --cluster_domain={{ dns_domain }} --kubeconfig={{ kube_config_dir}}/node-kubeconfig.yaml --config={{ kube_manifest_dir }} --resolv-conf={{ kube_resolv_conf }}"
+{% elif dns_setup|bool %}
 KUBELET_ARGS="--cluster_dns={{ dns_server }} --cluster_domain={{ dns_domain }} --kubeconfig={{ kube_config_dir}}/node-kubeconfig.yaml --config={{ kube_manifest_dir }} --resolv-conf={{ kube_resolv_conf }}"
 {% else %}
 KUBELET_ARGS="--kubeconfig={{ kube_config_dir}}/kubelet.kubeconfig --config={{ kube_manifest_dir }}"