First pass at Kubernetes support.

examples/kubernetes/README.markdown

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+# Vitess on Kubernetes
+
+This directory contains an example configuration for running Vitess on
+[Kubernetes](https://github.com/GoogleCloudPlatform/kubernetes/). Refer to the
+appropriate [Getting Started Guide](https://github.com/GoogleCloudPlatform/kubernetes/#contents)
+to get Kubernetes up and running if you haven't already. We currently test
+against HEAD, so you may want to build Kubernetes from the latest source.
+
+## ZooKeeper
+
+Once you have a running Kubernetes deployment, make sure
+*kubernetes/cluster/kubecfg.sh* is in your path, and then run:
+
+```
+vitess$ examples/kubernetes/zk-up.sh
+```
+
+This will create a quorum of ZooKeeper servers. Clients can connect to port 2181
+of any [minion](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/DESIGN.md#cluster-architecture)
+(assuming the firewall is set to allow it), and the Kubernetes proxy will
+load-balance the connection to any of the servers.
+
+A simple way to test out your ZooKeeper deployment is by logging into one of
+your minions and running the *zk* client utility inside Docker. For example, if
+you are running [Kubernetes on Google Compute Engine](https://github.com/GoogleCloudPlatform/kubernetes/blob/master/docs/getting-started-guides/gce.md):
+
+```
+# log in to a minion
+$ gcloud compute ssh kubernetes-minion-1
+
+# show zk command usage
+kubernetes-minion-1:~$ sudo docker run -ti --rm vitess/root zk
+
+# create a test node in ZooKeeper
+kubernetes-minion-1:~$ sudo docker run -ti --rm vitess/root zk -zk.addrs $HOSTNAME:2181 touch -p /zk/test_cell/vt
+
+# check that the node is there
+kubernetes-minion-1:~$ sudo docker run -ti --rm vitess/root zk -zk.addrs $HOSTNAME:2181 ls /zk/test_cell
+```
+
+To tear down the ZooKeeper deployment (again, with *kubecfg.sh* in your path):
+
+```
+vitess$ examples/kubernetes/zk-down.sh
+```

examples/kubernetes/zk-client-service.yaml

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+apiVersion: v1beta1
+kind: Service
+id: zk-client
+port: 2181
+containerPort: 2181
+selector:
+  name: zk
+labels:
+  name: zk

examples/kubernetes/zk-down.sh

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+#!/bin/bash
+
+# This is an example script that tears down the ZooKeeper servers started by
+# zk-up.sh. It assumes that kubernetes/cluster/kubecfg.sh is in the path.
+
+# Delete pods.
+for zkid in 1 2 3; do
+  echo "Deleting zk$zkid pod..."
+  kubecfg.sh delete pods/zk$zkid
+done
+
+# Delete client service.
+echo "Deleting zk-client service..."
+kubecfg.sh delete services/zk-client
+
+# Delete leader and election services.
+for zkid in 1 2 3; do
+  echo "Deleting zk$zkid-leader service..."
+  kubecfg.sh delete services/zk$zkid-leader
+
+  echo "Deleting zk$zkid-election service..."
+  kubecfg.sh delete services/zk$zkid-election
+done

examples/kubernetes/zk-pod-template.yaml

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+apiVersion: v1beta1
+kind: Pod
+id: zk{{zkid}}
+desiredState:
+  manifest:
+    version: v1beta1
+    id: zk{{zkid}}
+    containers:
+      - name: zk{{zkid}}
+        image: vitess/root
+        volumeMounts:
+          - name: syslog
+            mountPath: /dev/log
+          - name: vtdataroot
+            mountPath: /vt/vtdataroot
+        command: [sh, "-c", "chown vitess /vt/vtdataroot && su -p -c \"/vt/bin/zkctl -follow -zk.myid {{zkid}} -zk.cfg {{zkcfg}} init\" vitess"] 
+    volumes:
+      - name: syslog
+        source: {hostDir: {path: /dev/log}}
+      - name: vtdataroot
+        source: {emptyDir: {}}
+labels:
+  name: zk
+  zkid: {{zkid}}

examples/kubernetes/zk-service-template.yaml

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+apiVersion: v1beta1
+kind: Service
+id: zk{{zkid}}-{{svc}}
+port: {{port}}{{zkid}}
+containerPort: {{port}}{{zkid}}
+selector:
+  name: zk
+  zkid: {{zkid}}
+labels:
+  name: zk
+  zkid: {{zkid}}

examples/kubernetes/zk-up.sh

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+#!/bin/bash
+
+# This is an example script that creates a quorum of ZooKeeper servers.
+# It assumes that kubernetes/cluster/kubecfg.sh is in the path.
+
+set -e
+
+# List of all servers in the quorum.
+zkcfg=(\
+    '1@$SERVICE_HOST:28881:38881:2181' \
+    '2@$SERVICE_HOST:28882:38882:2181' \
+    '3@$SERVICE_HOST:28883:38883:2181' \
+    )
+printf -v zkcfg ",%s" "${zkcfg[@]}"
+zkcfg=${zkcfg:1}
+
+# Create the pods.
+echo "Creating zk pods..."
+for zkid in 1 2 3; do
+  cat zk-pod-template.yaml | \
+    sed -e "s/{{zkid}}/$zkid/g" -e "s/{{zkcfg}}/$zkcfg/g" | \
+    kubecfg.sh -c - create pods
+done
+
+# Create the client service, which will load-balance across all replicas.
+echo "Creating zk services..."
+kubecfg.sh -c zk-client-service.yaml create services
+
+# Create a service for the leader and election ports of each replica.
+# This is necessary because ZooKeeper servers need to know how to specifically
+# contact replica N (not just "any replica") in order to create a quorum.
+# We also have to append the zkid of each server to the port number, because
+# every service in Kubernetes needs a unique port number (for now).
+
+ports=( 2888 3888 )
+svcs=( leader election )
+
+for zkid in 1 2 3; do
+  for i in 0 1; do
+    port=${ports[$i]}
+    svc=${svcs[$i]}
+
+    cat zk-service-template.yaml | \
+      sed -e "s/{{zkid}}/$zkid/g" -e "s/{{port}}/$port/g" -e "s/{{svc}}/$svc/g" | \
+      kubecfg.sh -c - create services
+  done
+done