net=host + resolv.conf workaround.

We're using service discovery with our net=host pods but resolv.conf
doesn't point at kube-dns when net=host. This provides a workaround.
You can do this by creating a configmap called resolv-conf with a
resolv.conf from a non net=host pod, and you set:

enable_resolve_conf_net_host_workaround="yes"

Change-Id: Ic2ac1725f42ba66b89cd5869f3ec3a751aa66df8

kolla_kubernetes/commands/cmd_resource.py

@@ -90,6 +90,14 @@ class ResourceTemplate(ResourceBase):
                   " The vars dict is created by merging configuration files "
                   " from several sources before applying the dict to itself.")
         ),
+        parser.add_argument(
+            "-o",
+            "--output",
+            metavar="output",
+            default="yaml",
+            help=("Format output into one of [%s]" % (
+                "|".join(['yaml', 'json'])))
+        ),
         parser.add_argument(
             '--print-jinja-keys-regex',
             metavar='<print-jinja-keys-regex>',
@@ -150,6 +158,9 @@ class ResourceTemplate(ResourceBase):
         if skip_and_return:
             return res
 
+        if args.output == 'json':
+            res = json.dumps(yaml.load(res), indent=4)
+
         print(res)
 
 

services/neutron/neutron-dhcp-agent-daemonset.yml.j2

@@ -94,6 +94,11 @@ spec:
               readOnly: true
             - mountPath: /var/log/kolla/
               name: kolla-logs
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+            - mountPath: /etc/resolv.conf
+              name: resolv-conf
+              subPath: resolv.conf
+{%- endif %}
           env:
             - name: KOLLA_CONFIG_STRATEGY
               value: {{ config_strategy }}
@@ -128,3 +133,8 @@ spec:
             path: /var/lib/neutron/kolla/metadata_proxy
         - name: kolla-logs
           emptyDir: {}
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+        - name: resolv-conf
+          configMap:
+            name: resolv-conf
+{%- endif %}

services/neutron/neutron-l3-agent-daemonset.yml.j2

@@ -110,6 +110,11 @@ spec:
               readOnly: true
             - mountPath: /var/log/kolla/
               name: kolla-logs
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+            - mountPath: /etc/resolv.conf
+              name: resolv-conf
+              subPath: resolv.conf
+{%- endif %}
           env:
             - name: KOLLA_CONFIG_STRATEGY
               value: {{ config_strategy }}
@@ -144,3 +149,8 @@ spec:
             path: /var/lib/neutron/kolla/metadata_proxy
         - name: kolla-logs
           emptyDir: {}
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+        - name: resolv-conf
+          configMap:
+            name: resolv-conf
+{%- endif %}

services/neutron/neutron-metadata-agent-daemonset.yml.j2

@@ -45,6 +45,11 @@ spec:
               readOnly: true
             - mountPath: /var/log/kolla/
               name: kolla-logs
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+            - mountPath: /etc/resolv.conf
+              name: resolv-conf
+              subPath: resolv.conf
+{%- endif %}
           env:
             - name: KOLLA_CONFIG_STRATEGY
               value: {{ config_strategy }}
@@ -75,3 +80,8 @@ spec:
             path: /var/lib/neutron/kolla/metadata_proxy
         - name: kolla-logs
           emptyDir: {}
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+        - name: resolv-conf
+          configMap:
+            name: resolv-conf
+{%- endif %}

services/neutron/neutron-openvswitch-agent-daemonset.yml.j2

@@ -99,6 +99,11 @@ spec:
               readOnly: true
             - mountPath: /var/log/kolla/
               name: kolla-logs
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+            - mountPath: /etc/resolv.conf
+              name: resolv-conf
+              subPath: resolv.conf
+{%- endif %}
 
 # NOTE: (sbezverk) Linux bridge will be moved to its own file at the time of development
 # keeping it here just for future reference.
@@ -164,3 +169,8 @@ spec:
             path: /lib/modules
         - name: kolla-logs
           emptyDir: {}
+{%- if enable_resolve_conf_net_host_workaround == "yes" %}
+        - name: resolv-conf
+          configMap:
+            name: resolv-conf
+{%- endif %}

tools/setup-resolv-conf.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+NAMESPACE=$(kolla-kubernetes resource-template create bootstrap neutron-create-db -o json | jq -r '.metadata.namespace')
+TOOLBOX=$(kolla-kubernetes resource-template create bootstrap neutron-create-db -o json | jq -r '.spec.template.spec.containers[0].image')
+kubectl run -i --rm fetchresolv --restart=Never --namespace=$NAMESPACE --image=$TOOLBOX -- /bin/bash -c 'cat /etc/resolv.conf' | egrep '^search|^nameserver|^options' > /tmp/$$
+kubectl create configmap resolv-conf --from-file=resolv.conf=/tmp/$$ --namespace $NAMESPACE
+rm -f /tmp/$$
+