Add advanced net check for DNS K8s app

* Add an option to deploy K8s app to test e2e network connectivity
  and cluster DNS resolve via Kubedns for nethost/simple pods
  (defaults to false).
* Parametrize existing k8s apps templates with kube_namespace and
  kube_config_dir instead of hardcode.
* For CoreOS, ensure nameservers from inventory to be put in the
  first place to allow hostnet pods connectivity via short names
  or FQDN and hostnet agents to pass as well, if netchecker
  deployed.

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

roles/kubernetes-apps/ansible/tasks/calico-policy-controller.yml

@@ -1,5 +1,5 @@
 - name: Write calico-policy-controller yaml
-  template: src=calico-policy-controller.yml.j2 dest=/etc/kubernetes/calico-policy-controller.yml
+  template: src=calico-policy-controller.yml.j2 dest={{kube_config_dir}}/calico-policy-controller.yml
   when: inventory_hostname == groups['kube-master'][0]
 
 
@@ -7,7 +7,7 @@
   kube:
     name: "calico-policy-controller"
     kubectl: "{{bin_dir}}/kubectl"
-    filename: "/etc/kubernetes/calico-policy-controller.yml"
-    namespace: "kube-system"
+    filename: "{{kube_config_dir}}/calico-policy-controller.yml"
+    namespace: "{{kube_namespace}}"
     resource: "rs"
   when: inventory_hostname == groups['kube-master'][0]

roles/kubernetes-apps/ansible/tasks/main.yaml

@@ -1,6 +1,6 @@
 ---
 - name: Kubernetes Apps | Lay Down KubeDNS Template
-  template: src={{item.file}} dest=/etc/kubernetes/{{item.file}}
+  template: src={{item.file}} dest={{kube_config_dir}}/{{item.file}}
   with_items:
     - {file: kubedns-rc.yml, type: rc}
     - {file: kubedns-svc.yml, type: svc}
@@ -10,10 +10,10 @@
 - name: Kubernetes Apps | Start Resources
   kube:
     name: kubedns
-    namespace: kube-system
+    namespace: "{{ kube_namespace }}"
     kubectl: "{{bin_dir}}/kubectl"
     resource: "{{item.item.type}}"
-    filename: /etc/kubernetes/{{item.item.file}}
+    filename: "{{kube_config_dir}}/{{item.item.file}}"
     state: "{{item.changed | ternary('latest','present') }}"
   with_items: "{{ manifests.results }}"
   when: inventory_hostname == groups['kube-master'][0]
@@ -21,3 +21,7 @@
 - include: tasks/calico-policy-controller.yml
   when: ( enable_network_policy is defined and enable_network_policy == True ) or
     ( kube_network_plugin == 'canal' )
+
+- name: Kubernetes Apps | Netchecker
+  include: tasks/netchecker.yml
+  when: deploy_netchecker

roles/kubernetes-apps/ansible/tasks/netchecker.yml

@@ -0,0 +1,20 @@
+- name: Kubernetes Apps | Lay Down Netchecker Template
+  template: src={{item.file}} dest={{kube_config_dir}}/{{item.file}}
+  with_items:
+    - {file: netchecker-agent-ds.yml, type: ds, name: netchecker-agent}
+    - {file: netchecker-agent-hostnet-ds.yml, type: ds, name: netchecker-agent-hostnet}
+    - {file: netchecker-server-pod.yml, type: po, name: netchecker-server}
+    - {file: netchecker-server-svc.yml, type: svc, name: netchecker-service}
+  register: manifests
+  when: inventory_hostname == groups['kube-master'][0]
+
+- name: Kubernetes Apps | Start Netchecker Resources
+  kube:
+    name: "{{item.item.name}}"
+    namespace: "{{netcheck_namespace}}"
+    kubectl: "{{bin_dir}}/kubectl"
+    resource: "{{item.item.type}}"
+    filename: "{{kube_config_dir}}/{{item.item.file}}"
+    state: "{{item.changed | ternary('latest','present') }}"
+  with_items: "{{ manifests.results }}"
+  when: inventory_hostname == groups['kube-master'][0]