Move CNI config and add MTU support for calico-cni

- Move CNI configuration creation for Calico to appropriate
network_plugin role from kubernetes/node.
- Add support for MTU configuration in Calico.

roles/network_plugin/calico/defaults/main.yml

@@ -11,3 +11,8 @@ overwrite_hyperkube_cni: true
 
 calico_cert_dir: /etc/calico/certs
 etcd_cert_dir: /etc/ssl/etcd/ssl
+
+# You can set MTU value here. If left undefined or empty, it will
+# not be specified in calico CNI config, so Calico will use built-in
+# defaults. The value should be a number, not a string.
+# calico_mtu: 1500

roles/network_plugin/calico/tasks/main.yml

@@ -1,4 +1,10 @@
 ---
+- name: Calico | Write Calico cni config
+  template:
+    src: "cni-calico.conf.j2"
+    dest: "/etc/cni/net.d/10-calico.conf"
+    owner: kube
+
 - name: Calico | Set docker daemon options
   template:
     src: docker

roles/network_plugin/calico/templates/cni-calico.conf.j2

@@ -0,0 +1,23 @@
+{
+  "name": "calico-k8s-network",
+  "type": "calico",
+  "etcd_endpoints": "{{ etcd_access_endpoint }}",
+  "etcd_cert_file": "{{ etcd_cert_dir }}/node.pem",
+  "etcd_key_file": "{{ etcd_cert_dir }}/node-key.pem",
+  "etcd_ca_cert_file": "{{ etcd_cert_dir }}/ca.pem",
+  "log_level": "info",
+  "ipam": {
+    "type": "calico-ipam"
+  },
+{% if enable_network_policy is defined and enable_network_policy == True %}
+  "policy": {
+    "type": "k8s"
+  },
+{% endif %}
+{% if calico_mtu is defined and calico_mtu is number %}
+  "mtu": {{ calico_mtu }},
+{% endif %}
+  "kubernetes": {
+    "kubeconfig": "{{ kube_config_dir }}/node-kubeconfig.yaml"
+  }
+}