Cannot ping ClusterIP from inside the pod and DNS is not working for external domains like google.com
<p>I have installed Kubernetes on Bare-metal/Ubuntu. I am on <code>6b649d7f9f2b09ca8b0dd8c0d3e14dcb255432d1</code> commit in git. I used <code>cd kubernetes/cluster; KUBERNETES_PROVIDER=ubuntu ./kube-up.sh</code> followed by <code>cd kubernetes/cluster/ubuntu; ./deployAddons.sh</code> to start the cluster. Everything went fine and the cluster got up.</p>

<p>My <code>/ubuntu/config-default.sh</code> is as follows:</p>

<pre><code># Define all your cluster nodes, MASTER node comes first"
# And separated with blank space like &lt;user_1@ip_1&gt; &lt;user_2@ip_2&gt; &lt;user_3@ip_3&gt; 
export nodes=${nodes:-"root@192.168.48.170 root@192.168.48.180"}

# Define all your nodes role: a(master) or i(minion) or ai(both master and minion), must be the order same 
role=${role:-"ai i"}
# If it practically impossible to set an array as an environment variable
# from a script, so assume variable is a string then convert it to an array
export roles=($role)

# Define minion numbers
export NUM_NODES=${NUM_NODES:-2}
# define the IP range used for service cluster IPs.
# according to rfc 1918 ref: https://tools.ietf.org/html/rfc1918 choose a private ip range here.
export SERVICE_CLUSTER_IP_RANGE=${SERVICE_CLUSTER_IP_RANGE:-192.168.3.0/24}  # formerly PORTAL_NET
# define the IP range used for flannel overlay network, should not conflict with above SERVICE_CLUSTER_IP_RANGE
export FLANNEL_NET=${FLANNEL_NET:-172.16.0.0/16}

# Optionally add other contents to the Flannel configuration JSON
# object normally stored in etcd as /coreos.com/network/config.  Use
# JSON syntax suitable for insertion into a JSON object constructor
# after other field name:value pairs.  For example:
# FLANNEL_OTHER_NET_CONFIG=', "SubnetMin": "172.16.10.0", "SubnetMax": "172.16.90.0"'

export FLANNEL_OTHER_NET_CONFIG
FLANNEL_OTHER_NET_CONFIG=''

# Admission Controllers to invoke prior to persisting objects in cluster
export ADMISSION_CONTROL=NamespaceLifecycle,LimitRanger,ServiceAccount,ResourceQuota,SecurityContextDeny

# Path to the config file or directory of files of kubelet
export KUBELET_CONFIG=${KUBELET_CONFIG:-""}

# A port range to reserve for services with NodePort visibility
SERVICE_NODE_PORT_RANGE=${SERVICE_NODE_PORT_RANGE:-"30000-32767"}

# Optional: Enable node logging.
ENABLE_NODE_LOGGING=false
LOGGING_DESTINATION=${LOGGING_DESTINATION:-elasticsearch}

# Optional: When set to true, Elasticsearch and Kibana will be setup as part of the cluster bring up.
ENABLE_CLUSTER_LOGGING=false
ELASTICSEARCH_LOGGING_REPLICAS=${ELASTICSEARCH_LOGGING_REPLICAS:-1}

# Optional: When set to true, heapster, Influxdb and Grafana will be setup as part of the cluster bring up.
ENABLE_CLUSTER_MONITORING="${KUBE_ENABLE_CLUSTER_MONITORING:-true}"

# Extra options to set on the Docker command line.  This is useful for setting
# --insecure-registry for local registries.
DOCKER_OPTS=${DOCKER_OPTS:-""}

# Extra options to set on the kube-proxy command line.  This is useful
# for selecting the iptables proxy-mode, for example.
KUBE_PROXY_EXTRA_OPTS=${KUBE_PROXY_EXTRA_OPTS:-""}

# Optional: Install cluster DNS.
ENABLE_CLUSTER_DNS="${KUBE_ENABLE_CLUSTER_DNS:-true}"
# DNS_SERVER_IP must be a IP in SERVICE_CLUSTER_IP_RANGE
DNS_SERVER_IP=${DNS_SERVER_IP:-"192.168.3.10"}
DNS_DOMAIN=${DNS_DOMAIN:-"cluster.local"}
DNS_REPLICAS=${DNS_REPLICAS:-1}

# Optional: Install Kubernetes UI
ENABLE_CLUSTER_UI="${KUBE_ENABLE_CLUSTER_UI:-true}"

# Optional: Enable setting flags for kube-apiserver to turn on behavior in active-dev
RUNTIME_CONFIG="--basic-auth-file=password.csv"

# Optional: Add http or https proxy when download easy-rsa.
# Add envitonment variable separated with blank space like "http_proxy=http://10.x.x.x:8080 https_proxy=https://10.x.x.x:8443"
PROXY_SETTING=${PROXY_SETTING:-""}

DEBUG=${DEBUG:-"false"}
</code></pre>

<p>Then, I created a pod using the following yml file:</p>

<pre><code>apiVersion: v1
kind: Pod
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  containers:
  - name: nginx
    image: nginx
    ports:
    - containerPort: 80
</code></pre>

<p>And a service using the following yml:</p>

<pre><code>apiVersion: v1
kind: Service
metadata:
  name: nginx-service
spec:
  ports:
  - port: 8000
    targetPort: 80
    protocol: TCP
  selector:
    app: nginx
  type: NodePort
</code></pre>

<p>Then, I got into the started container terminal using <code>docker exec -it [CONTAINER_ID] bash</code>. There are mainly two problems:</p>

<ol>
<li>I cannot ping external domains like google.com, but I can ping external IPs like 8.8.8.8. So the container has internet access.</li>
<li>Internal services resolve to correct Internal ClusterIPs, but I cannot ping that IP from inside the container.</li>
</ol>

<p>The host's <code>/etc/resolve.conf</code> file is as follows:</p>

<pre><code>nameserver 8.8.8.8
nameserver 127.0.1.1
</code></pre>

<p>The container's <code>/etc/resolve.conf</code> file is as follows:</p>

<pre><code>search default.svc.cluster.local svc.cluster.local cluster.local
nameserver 192.168.3.10
nameserver 8.8.8.8
nameserver 127.0.1.1
options ndots:5
</code></pre>

<p>Regarding the first problem, I think it could be related to either SkyDNS nameservers  misconfigurarion or a custom configuration that I have to do but I am not aware of.</p>

<p>However, I dont have any idea about why the containers cannot ping ClusterIPs.</p>

<p>Any workarounds?</p>