Add PaddlePaddle QuickStart Demo on Kubernetes

doc_cn/build_and_install/paddle_on_kubernetes.md

+# Paddle On Kubernetes
+
+## 制作Docker镜像
+
+  本文使用QucikStart的例子来作为镜像，详细的Paddle镜像请参考[Docker installation guide](http://www.paddlepaddle.org/doc/build/docker_install.html),使用paddledev/paddle:cpu-demo-latest作为基础镜像。
+
+### 运行容器
+
+```
+$ docker run --name quick_start_data -it paddledev/paddle:cpu-demo-latest
+```
+进入容器`/root/paddle/demo/quick_start/data`目录，使用`get_data.sh`下载数据
+
+```
+$ root@fbd1f2bb71f4:~/paddle/demo/quick_start/data# ./get_data.sh
+
+Downloading Amazon Electronics reviews data...
+--2016-10-31 01:33:43--  http://snap.stanford.edu/data/amazon/productGraph/categoryFiles/reviews_Electronics_5.json.gz
+Resolving snap.stanford.edu (snap.stanford.edu)... 171.64.75.80
+Connecting to snap.stanford.edu (snap.stanford.edu)|171.64.75.80|:80... connected.
+HTTP request sent, awaiting response... 200 OK
+Length: 495854086 (473M) [application/x-gzip]
+Saving to: 'reviews_Electronics_5.json.gz'
+
+ 0% [                                                                ] 874,279     64.7KB/s  eta 2h 13m
+
+```
+
+下载完数据后，修改`/root/paddle/demo/quick_start/train.sh`文件，内容如下（增加了一条cd命令）
+```
+set -e
+cd /root/paddle/demo/quick_start
+cfg=trainer_config.lr.py
+#cfg=trainer_config.emb.py
+#cfg=trainer_config.cnn.py
+#cfg=trainer_config.lstm.py
+#cfg=trainer_config.bidi-lstm.py
+#cfg=trainer_config.db-lstm.py
+paddle train \
+  --config=$cfg \
+  --save_dir=./output \
+  --trainer_count=4 \
+  --log_period=20 \
+  --num_passes=15 \
+  --use_gpu=false \
+  --show_parameter_stats_period=100 \
+  --test_all_data_in_one_period=1 \
+  2>&1 | tee 'train.log'
+```
+
+### 提交镜像
+
+下载完数据后，退出容器，使用`docker commit`命令创建新镜像。
+
+```
+$ docker commit quick_start_data mypaddle/paddle:quickstart
+```
+
+## 使用 Kubernetes 进行训练
+
+### 编写yaml文件
+
+在训练时，输出结果可能会随着容器的消耗而被删除，需要在创建Job时，挂载卷。使用前面构造的镜像，可以创建一个Kubernetes Job，简单的yaml文件如下：
+
+```
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: quickstart
+spec:
+  parallelism: 1
+  completions: 1
+  template:
+    metadata:
+      name: quickstart
+    spec:
+      volumes:
+      - name: output
+        hostPath: 
+          path: /home/work/paddle_output     
+      containers:
+      - name: pi
+        image: mypaddle/paddle:quickstart
+        command: ["bin/bash",  "-c", "/root/paddle/demo/quick_start/train.sh"]
+        volumeMounts:
+        - name: output
+          mountPath: /root/paddle/demo/quick_start/output
+      restartPolicy: Never
+```
+
+### 创建Paddle Job
+
+使用上文创建的yaml文件创建kubernetes job，命令为：
+
+```
+$ kubectl  create -f paddle.yaml
+```
+
+查看job的详细情况：
+
+```
+$ kubectl  get job
+NAME         DESIRED   SUCCESSFUL   AGE
+quickstart   1         0            58s
+
+$ kubectl  describe job quickstart
+Name:		quickstart
+Namespace:	default
+Image(s):	registry.baidu.com/public/paddle:cpu-demo-latest
+Selector:	controller-uid=f120da72-9f18-11e6-b363-448a5b355b84
+Parallelism:	1
+Completions:	1
+Start Time:	Mon, 31 Oct 2016 11:20:16 +0800
+Labels:		controller-uid=f120da72-9f18-11e6-b363-448a5b355b84,job-name=quickstart
+Pods Statuses:	0 Running / 1 Succeeded / 0 Failed
+Volumes:
+  output:
+    Type:	HostPath (bare host directory volume)
+    Path:	/home/work/paddle_output
+Events:
+  FirstSeen	LastSeen	Count	From			SubobjectPath	Type		Reason			Message
+  ---------	--------	-----	----			-------------	--------	------			-------
+  1m		1m		1	{job-controller }			Normal		SuccessfulCreate	Created pod: quickstart-fa0wx
+```
+
+### 查看训练结果
+
+根据job对应的pod信息，可以查看此Pod运行的宿主机。
+
+```
+kubectl  describe pod quickstart-fa0wx
+Name:		quickstart-fa0wx
+Namespace:	default
+Node:		paddle-demo-let02/10.206.202.44
+Start Time:	Mon, 31 Oct 2016 11:20:17 +0800
+Labels:		controller-uid=f120da72-9f18-11e6-b363-448a5b355b84,job-name=quickstart
+Status:		Succeeded
+IP:		10.0.0.9
+Controllers:	Job/quickstart
+Containers:
+  quickstart:
+    Container ID:	docker://b8561f5c79193550d64fa47418a9e67ebdd71546186e840f88de5026b8097465
+    Image:		registry.baidu.com/public/paddle:cpu-demo-latest
+    Image ID:		docker://18e457ce3d362ff5f3febf8e7f85ffec852f70f3b629add10aed84f930a68750
+    Port:
+    Command:
+      bin/bash
+      -c
+      /root/paddle/demo/quick_start/train.sh
+    QoS Tier:
+      cpu:		BestEffort
+      memory:		BestEffort
+    State:		Terminated
+      Reason:		Completed
+      Exit Code:	0
+      Started:		Mon, 31 Oct 2016 11:20:20 +0800
+      Finished:		Mon, 31 Oct 2016 11:21:46 +0800
+    Ready:		False
+    Restart Count:	0
+    Environment Variables:
+Conditions:
+  Type		Status
+  Ready 	False
+Volumes:
+  output:
+    Type:	HostPath (bare host directory volume)
+    Path:	/home/work/paddle_output
+```
+
+登录宿主机，查看结果。
+
+```
+[root@paddle-demo-let02 paddle_output]# ll
+total 60
+drwxr-xr-x 2 root root 4096 Oct 31 11:20 pass-00000
+drwxr-xr-x 2 root root 4096 Oct 31 11:20 pass-00001
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00002
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00003
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00004
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00005
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00006
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00007
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00008
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00009
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00010
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00011
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00012
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00013
+drwxr-xr-x 2 root root 4096 Oct 31 11:21 pass-00014
+```
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