Improve docs in module4

Author: Mercurio

module4/1.simple-pod.MD

@@ -1,23 +1,32 @@
+## Simple pod demo
 
-## simple pod demo
-### run nginx as webserver
-```
+### Run nginx as webserver
+
+```shell
 $ kubectl run --image=nginx nginx
 $ kubectl run --image=nginx nginx --restart='Always'
 ```
-### show running pod
-```
+
+### Show running pod
+
+```shell
 $ kubectl get po --show-labels -owide -w
 ```
-### expose svc
-```
+
+### Expose svc
+
+```shell
 $ kubectl expose deploy nginx --selector run=nginx --port=80 --type=NodePort
 ```
-### check svc detail
-```
+
+### Check svc detail
+
+```shell
 $ kubectl get svc
 ```
-### access service
-```
+
+### Access service
+
+```shell
 $ curl 192.168.34.2:<nodeport>
 ```

module4/2.run-envoy-with-configmap.MD

@@ -1,18 +1,27 @@
-## run envoy
-```
+## Run envoy
+
+```shell
 $ kubectl create configmap envoy-config --from-file=envoy.yaml
 $ kubectl create -f envoy-deploy.yaml
 $ kubectl expose deploy envoy --selector run=envoy --port=10000 --type=NodePort
 ```
-## access service
-```
+
+## Access service
+
+```shell
 $ curl <NODE IP Address>:<NodePort>
+```
+
 Notices: Node IP Address base on your kubernetes cluster.
 
 Example:
+
+```shell
 $ curl 192.168.34.2:<nodeport>
 ```
-## scale up/down/failover
-```
+
+## Scale up/down/failover
+
+```shell
 $ kubectl scale deploy <deployment-name> --replicas=<n>
 ```

module4/3.understand-configmap.MD

@@ -1,17 +1,20 @@
-# configmap
-```
+# ConfigMap
+
+```sh
 cat game.properties
 
 #configmap from file
 kubectl create configmap game-config --from-file=game.properties
 kubectl create configmap game-env-config --from-env-file=game.properties
 kubectl get configmap -oyaml game-config
 ```
-## configmap from literal
-```
+
+## ConfigMap from literal
+
+```sh
 kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm
 #downward api pod
 kubectl create -f downward-api-pod.yaml
 kubectl get po downward-api-pod
 kubectl logs -f downward-api-pod
-```
+```

module4/4.configmap-volume.MD

@@ -1,6 +1,7 @@
-# volume
-```
+# Volume
+
+```sh
 kubectl create -f configmap-volume-pod.yaml
 kubectl get po
 kubectl logs -f configmap-volume-pod
-```
+```

module4/5.readiness-probe.MD

@@ -1,4 +1,5 @@
-# readiness probe
-```
+# Readiness probe
+
+```sh
 kubectl create -f centos-readiness.yaml
-```
+```

module4/6.get-obj-columns.MD

@@ -1,4 +1,5 @@
-## get object by columns
+## Get object by columns
+
+```sh
+kubectl get svc -o=custom-columns=NAME:.metadata.name,CREATED:'.metadata.annotations'
 ```
-kubectl get svc  -o=custom-columns=NAME:.metadata.name,CREATED:'.metadata.annotations'
-```

module4/readme.md

@@ -11,22 +11,23 @@
 
 #### Envoy
 
-- [中文介绍](https://cloudnative.to/blog/what-is-envoy/) 
+- [中文介绍](https://cloudnative.to/blog/what-is-envoy/)
 
-- [中文翻译文档](https://cloudnative.to/envoy/intro/intro.html) 
+- [中文翻译文档](https://cloudnative.to/envoy/intro/intro.html)
 
-官方资料
+#### 官方资料
 
 - [英文文档](https://www.envoyproxy.io/docs/envoy/latest/intro/what_is_envoy)
 
 - [sandboxes (新手入门必须试试)](https://www.envoyproxy.io/docs/envoy/latest/start/sandboxes/)
 
-博客
+#### 博客
+
 - FuckCloudNative
   - https://fuckcloudnative.io/tags/envoy/page/2/
   - https://fuckcloudnative.io/tags/envoy/page/1/
 
-### Kubernetes 
+### Kubernetes
 
 - [Architecting Kubernetes clusters — choosing a worker node size](https://learnk8s.io/kubernetes-node-size)