diff --git a/.vuepress/config.js b/.vuepress/config.js
index 1ac0558..13a3e26 100644
--- a/.vuepress/config.js
+++ b/.vuepress/config.js
@@ -19,6 +19,8 @@ module.exports = {
     ['link', {rel: "stylesheet", href: "/java-script-dist/swiper-4.5.0/css/swiper.min.css"}],    
     ['script', {src: '/java-script-dist/swiper-4.5.0/js/swiper.min.js'}],
     // ['script', {type: 'text/javascript', src: 'https://tajs.qq.com/stats?sId=66467492', charset: 'UTF-8'}]
+    ['script', { 'data-ad-client': "ca-pub-3313149841665250", async: true, src: "https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"}],
+    // <script data-ad-client="ca-pub-3313149841665250" async src="https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
   ],
   markdown: {
     toc: { includeLevel: [2, 3] },
diff --git a/.vuepress/public/images/search.svg b/.vuepress/public/images/search.svg
new file mode 100644
index 0000000..03d8391
--- /dev/null
+++ b/.vuepress/public/images/search.svg
@@ -0,0 +1 @@
+<?xml version="1.0" encoding="UTF-8"?><svg xmlns="http://www.w3.org/2000/svg" width="12" height="13"><g stroke-width="2" stroke="#aaa" fill="none"><path d="M11.29 11.71l-4-4"/><circle cx="5" cy="5" r="4"/></g></svg>
diff --git a/.vuepress/public/statics/learning/logs/counter-sidecar-pod.yaml b/.vuepress/public/statics/learning/logs/counter-sidecar-pod.yaml
new file mode 100644
index 0000000..87bd198
--- /dev/null
+++ b/.vuepress/public/statics/learning/logs/counter-sidecar-pod.yaml
@@ -0,0 +1,38 @@
+apiVersion: v1
+kind: Pod
+metadata:
+  name: counter
+spec:
+  containers:
+  - name: count
+    image: busybox
+    args:
+    - /bin/sh
+    - -c
+    - >
+      i=0;
+      while true;
+      do
+        echo "$i: $(date)" >> /var/log/1.log;
+        echo "$(date) INFO $i" >> /var/log/2.log;
+        i=$((i+1));
+        sleep 1;
+      done
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  - name: count-log-1
+    image: busybox
+    args: [/bin/sh, -c, 'tail -n+1 -f /var/log/1.log']
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  - name: count-log-2
+    image: busybox
+    args: [/bin/sh, -c, 'tail -n+1 -f /var/log/2.log']
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  volumes:
+  - name: varlog
+    emptyDir: {}
diff --git a/.vuepress/theme/components/BdSearchBox.vue b/.vuepress/theme/components/BdSearchBox.vue
new file mode 100644
index 0000000..e1d8342
--- /dev/null
+++ b/.vuepress/theme/components/BdSearchBox.vue
@@ -0,0 +1,283 @@
+<template>
+  <div class="search-box">
+    <input
+      id="bdcsMain"
+      @input="query = $event.target.value"
+      aria-label="Search"
+      :value="query"
+      :class="{ 'focused': focused }"
+      :placeholder="placeholder"
+      autocomplete="off"
+      spellcheck="false"
+      @focus="focused = true"
+      @blur="focused = false"
+      @keyup.enter="go(focusIndex)"
+      @keyup.up="onUp"
+      @keyup.down="onDown"
+      ref="input"
+    >
+    <ul
+      class="suggestions"
+      v-if="showSuggestions"
+      :class="{ 'align-right': alignRight }"
+      @mouseleave="unfocus"
+    >
+      <li
+        class="suggestion"
+        v-for="(s, i) in suggestions"
+        :class="{ focused: i === focusIndex }"
+        @mousedown="go(i)"
+        @mouseenter="focus(i)"
+      >
+        <a :href="s.path" @click.prevent>
+          <span class="page-title">{{ s.title || s.path }}</span>
+          <span v-if="s.header" class="header">&gt; {{ s.header.title }}</span>
+        </a>
+      </li>
+    </ul>
+  </div>
+</template>
+
+<script>
+/* global SEARCH_MAX_SUGGESTIONS, SEARCH_PATHS, SEARCH_HOTKEYS */
+export default {
+  data () {
+    return {
+      query: '',
+      focused: false,
+      focusIndex: 0,
+      placeholder: undefined
+    }
+  },
+
+  mounted () {
+    this.placeholder = this.$site.themeConfig.searchPlaceholder || ''
+    document.addEventListener('keydown', this.onHotkey)
+  },
+
+  beforeDestroy () {
+    document.removeEventListener('keydown', this.onHotkey)
+  },
+
+  computed: {
+    showSuggestions () {
+      return (
+        this.focused
+        && this.suggestions
+        && this.suggestions.length
+      )
+    },
+
+    suggestions () {
+      const query = this.query.trim().toLowerCase()
+      if (!query) {
+        return
+      }
+
+      const { pages } = this.$site
+      const max = this.$site.themeConfig.searchMaxSuggestions || SEARCH_MAX_SUGGESTIONS
+      const localePath = this.$localePath
+      const matches = item => (
+        item
+        && item.title
+        && item.title.toLowerCase().indexOf(query) > -1
+      )
+      const res = []
+      for (let i = 0; i < pages.length; i++) {
+        if (res.length >= max) break
+        const p = pages[i]
+        // filter out results that do not match current locale
+        if (this.getPageLocalePath(p) !== localePath) {
+          continue
+        }
+
+        // filter out results that do not match searchable paths
+        if (!this.isSearchable(p)) {
+          continue
+        }
+
+        if (matches(p)) {
+          res.push(p)
+        } else if (p.headers) {
+          for (let j = 0; j < p.headers.length; j++) {
+            if (res.length >= max) break
+            const h = p.headers[j]
+            if (matches(h)) {
+              res.push(Object.assign({}, p, {
+                path: p.path + '#' + h.slug,
+                header: h
+              }))
+            }
+          }
+        }
+      }
+      return res
+    },
+
+    // make suggestions align right when there are not enough items
+    alignRight () {
+      const navCount = (this.$site.themeConfig.nav || []).length
+      const repo = this.$site.repo ? 1 : 0
+      return navCount + repo <= 2
+    }
+  },
+
+  methods: {
+    getPageLocalePath (page) {
+      for (const localePath in this.$site.locales || {}) {
+        if (localePath !== '/' && page.path.indexOf(localePath) === 0) {
+          return localePath
+        }
+      }
+      return '/'
+    },
+
+    isSearchable (page) {
+      let searchPaths = SEARCH_PATHS
+
+      // all paths searchables
+      if (searchPaths === null) { return true }
+
+      searchPaths = Array.isArray(searchPaths) ? searchPaths : new Array(searchPaths)
+
+      return searchPaths.filter(path => {
+        return page.path.match(path)
+      }).length > 0
+    },
+
+    onHotkey (event) {
+      if (event.srcElement === document.body && SEARCH_HOTKEYS.includes(event.key)) {
+        this.$refs.input.focus()
+        event.preventDefault()
+      }
+    },
+
+    onUp () {
+      if (this.showSuggestions) {
+        if (this.focusIndex > 0) {
+          this.focusIndex--
+        } else {
+          this.focusIndex = this.suggestions.length - 1
+        }
+      }
+    },
+
+    onDown () {
+      if (this.showSuggestions) {
+        if (this.focusIndex < this.suggestions.length - 1) {
+          this.focusIndex++
+        } else {
+          this.focusIndex = 0
+        }
+      }
+    },
+
+    go (i) {
+      if (!this.showSuggestions) {
+        return
+      }
+      this.$router.push(this.suggestions[i].path)
+      this.query = ''
+      this.focusIndex = 0
+    },
+
+    focus (i) {
+      this.focusIndex = i
+    },
+
+    unfocus () {
+      this.focusIndex = -1
+    }
+  }
+}
+</script>
+
+<style lang="stylus">
+.search-box
+  display inline-block
+  position relative
+  margin-right 1rem
+  input
+    cursor text
+    width 10rem
+    height: 2rem
+    color lighten($textColor, 25%)
+    display inline-block
+    border 1px solid darken($borderColor, 10%)
+    border-radius 2rem
+    font-size 0.9rem
+    line-height 2rem
+    padding 0 0.5rem 0 2rem
+    outline none
+    transition all .2s ease
+    background #fff url(/images/search.svg) 0.6rem 0.5rem no-repeat
+    background-size 1rem
+    &:focus
+      cursor auto
+      border-color $accentColor
+  .suggestions
+    background #fff
+    width 20rem
+    position absolute
+    top 1.5rem
+    border 1px solid darken($borderColor, 10%)
+    border-radius 6px
+    padding 0.4rem
+    list-style-type none
+    &.align-right
+      right 0
+  .suggestion
+    line-height 1.4
+    padding 0.4rem 0.6rem
+    border-radius 4px
+    cursor pointer
+    a
+      white-space normal
+      color lighten($textColor, 35%)
+      .page-title
+        font-weight 600
+      .header
+        font-size 0.9em
+        margin-left 0.25em
+    &.focused
+      background-color #f3f4f5
+      a
+        color $accentColor
+
+@media (max-width: $MQNarrow)
+  .search-box
+    input
+      cursor pointer
+      width 0
+      border-color transparent
+      position relative
+      &:focus
+        cursor text
+        left 0
+        width 10rem
+
+// Match IE11
+@media all and (-ms-high-contrast: none)
+  .search-box input
+    height 2rem
+
+@media (max-width: $MQNarrow) and (min-width: $MQMobile)
+  .search-box
+    .suggestions
+      left 0
+
+@media (max-width: $MQMobile)
+  .search-box
+    margin-right 0
+    input
+      left 1rem
+    .suggestions
+      right 0
+
+@media (max-width: $MQMobileNarrow)
+  .search-box
+    .suggestions
+      width calc(100vw - 4rem)
+    input:focus
+      width 8rem
+</style>
diff --git a/.vuepress/theme/components/Navbar.vue b/.vuepress/theme/components/Navbar.vue
index 883d498..1f62eb3 100644
--- a/.vuepress/theme/components/Navbar.vue
+++ b/.vuepress/theme/components/Navbar.vue
@@ -50,6 +50,7 @@
 <script>
 import AlgoliaSearchBox from '@AlgoliaSearchBox'
 import SearchBox from '@SearchBox'
+// import SearchBox from './BdSearchBox'
 import SidebarButton from '@theme/components/SidebarButton.vue'
 import NavLinks from '@theme/components/NavLinks.vue'
 
diff --git a/.vuepress/theme/components/PageVssue.vue b/.vuepress/theme/components/PageVssue.vue
index 8504149..72e53c2 100644
--- a/.vuepress/theme/components/PageVssue.vue
+++ b/.vuepress/theme/components/PageVssue.vue
@@ -10,6 +10,20 @@
         <Vssue ref="vssue" :title="$page.path" :options="options"/>
       </div>
     </div>
+    <script type="text/javascript">
+    (function(){
+        var bp = document.createElement('script');
+        var curProtocol = window.location.protocol.split(':')[0];
+        if (curProtocol === 'https') {
+            bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
+        }
+        else {
+            bp.src = 'http://push.zhanzhang.baidu.com/push.js';
+        }
+        var s = document.getElementsByTagName('script')[0];
+        s.parentNode.insertBefore(bp, s);
+    })();
+    </script>
   </div>
 </template>
 
diff --git a/.vuepress/theme/layouts/Layout.vue b/.vuepress/theme/layouts/Layout.vue
index df85272..153531e 100644
--- a/.vuepress/theme/layouts/Layout.vue
+++ b/.vuepress/theme/layouts/Layout.vue
@@ -31,20 +31,6 @@
       <StarGazer/>
     </div>
     <div slot="page-bottom" class="bottom-description">Copyright © 2019-present 邵欢庆 <a href="http://www.eigpay.com" target="_blank">仁聚汇通</a> | 京ICP备19008693号-2
-    <script>
-    (function(){
-        var bp = document.createElement('script');
-        var curProtocol = window.location.protocol.split(':')[0];
-        if (curProtocol === 'https') {
-            bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
-        }
-        else {
-            bp.src = 'http://push.zhanzhang.baidu.com/push.js';
-        }
-        var s = document.getElementsByTagName('script')[0];
-        s.parentNode.insertBefore(bp, s);
-    })();
-    </script>
     </div>
   </ParentLayout>
 </template>
diff --git a/.vuepress/theme/layouts/LearningLayout.vue b/.vuepress/theme/layouts/LearningLayout.vue
index 5b84d97..9a4a86d 100644
--- a/.vuepress/theme/layouts/LearningLayout.vue
+++ b/.vuepress/theme/layouts/LearningLayout.vue
@@ -46,20 +46,6 @@
       </div>
     </div>
     <div slot="page-bottom" class="bottom-description">Copyright © 2019-present 邵欢庆 <a href="http://www.eigpay.com" target="_blank">仁聚汇通</a> | 京ICP备19008693号-2
-    <script>
-    (function(){
-        var bp = document.createElement('script');
-        var curProtocol = window.location.protocol.split(':')[0];
-        if (curProtocol === 'https') {
-            bp.src = 'https://zz.bdstatic.com/linksubmit/push.js';
-        }
-        else {
-            bp.src = 'http://push.zhanzhang.baidu.com/push.js';
-        }
-        var s = document.getElementsByTagName('script')[0];
-        s.parentNode.insertBefore(bp, s);
-    })();
-    </script>
     </div>
   </ParentLayout>
 </template>
diff --git a/.vuepress/theme/search.svg b/.vuepress/theme/search.svg
new file mode 100644
index 0000000..03d8391
--- /dev/null
+++ b/.vuepress/theme/search.svg
@@ -0,0 +1 @@
+<?xml version="1.0" encoding="UTF-8"?><svg xmlns="http://www.w3.org/2000/svg" width="12" height="13"><g stroke-width="2" stroke="#aaa" fill="none"><path d="M11.29 11.71l-4-4"/><circle cx="5" cy="5" r="4"/></g></svg>
diff --git a/README.md b/README.md
index 4805f84..13ae36e 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ features:
   link: /learning/k8s-practice/ocp
 ---
 
-## 简介
+# Kuboard简介
 
 Kuboard 是一款基于 Kubernetes 的微服务管理界面。
 
diff --git a/learning/k8s-advanced/logs/cluster.assets/logging-from-application.png b/learning/k8s-advanced/logs/cluster.assets/logging-from-application.png
new file mode 100644
index 0000000..67dfd9d
Binary files /dev/null and b/learning/k8s-advanced/logs/cluster.assets/logging-from-application.png differ
diff --git a/learning/k8s-advanced/logs/cluster.assets/logging-with-node-agent.png b/learning/k8s-advanced/logs/cluster.assets/logging-with-node-agent.png
new file mode 100644
index 0000000..52748c0
Binary files /dev/null and b/learning/k8s-advanced/logs/cluster.assets/logging-with-node-agent.png differ
diff --git a/learning/k8s-advanced/logs/cluster.assets/logging-with-sidecar-agent.png b/learning/k8s-advanced/logs/cluster.assets/logging-with-sidecar-agent.png
new file mode 100644
index 0000000..a9816da
Binary files /dev/null and b/learning/k8s-advanced/logs/cluster.assets/logging-with-sidecar-agent.png differ
diff --git a/learning/k8s-advanced/logs/cluster.assets/logging-with-streaming-sidecar.png b/learning/k8s-advanced/logs/cluster.assets/logging-with-streaming-sidecar.png
new file mode 100644
index 0000000..cc9fd0d
Binary files /dev/null and b/learning/k8s-advanced/logs/cluster.assets/logging-with-streaming-sidecar.png differ
diff --git a/learning/k8s-advanced/logs/cluster.md b/learning/k8s-advanced/logs/cluster.md
index d251a01..73b138d 100644
--- a/learning/k8s-advanced/logs/cluster.md
+++ b/learning/k8s-advanced/logs/cluster.md
@@ -9,4 +9,209 @@ meta:
 
 # 集群级别的日志
 
-正在撰写...
+Kubernetes 中并不默认提供集群级别的日志，不过，有许多种途径可以和集群级别的日志整合。例如：
+* 在每个节点上配置日志代理
+* 在应用程序的 Pod 中包含一个专门用于收集日志的 sidecar 容器
+* 从应用程序中直接推送日志到日志存储端
+
+
+
+## 在节点上配置日志代理
+
+![Kubernetes教程_在节点上配置日志代理](./cluster.assets/logging-with-node-agent.png)
+
+如上图所示，通过在每个节点上配置一个节点级别的 logging-agent，您就可以实现集群级别的日志（cluster-level logging）。该 logging-agent 专门用来将节点上的日志文件中的日志推送到日志的后端存储。在 [节点日志的存储](./node.html#日志存储) 中，我们已经了解到，所有应用程序的标准输出都被使用 docker 的 [logging driver](https://docs.docker.com/engine/admin/logging/overview) 存储到了节点的 `/var/log/containers` 目录下（K8S 的默认配置）。因此，节点级别的 logging-agent 应该能够将该目录下的日志文件发送到日志后端。[系统组件的日志](./node.html#系统组件的日志) 可以考虑一下是否要推送到日志后端。
+
+logging-agent 必须运行在每一个节点上，可以选择的实现方式有：
+* DaemonSet <Badge type="success">推荐</Badge>
+* Static Pod <Badge type="error">Deprecated</Badge>
+* 节点上的一个原生进程 <Badge type="error">Deprecated</Badge>。
+
+对于 Kubernetes 集群来说，使用节点级别的 logging-agent 实现集群级别的日志（cluster-level logging）是使用最广泛也最为推荐的一种做法，因为这种做法只为每个节点创建了一个 logging-agent，且无需对节点上的容器化应用程序做任何修改。当然，只有当应用程序使用 stdout 和 stderr 记录日志时，节点级别的 logging-agent 才能生效。Kubernetes 默认安装并不指定 logging-agent，但是Kubernetes默认打包了两种 logging-agent 以供选择：
+* [Stackdriver Logging](https://kubernetes.io/docs/user-guide/logging/stackdriver) 配合 Google Cloud Platform
+* [Elasticsearch](https://kubernetes.io/docs/user-guide/logging/elasticsearch) 
+
+<!-- FIXME 设置 Elasticsearch 以收集日志-->
+
+这两个选项都使用自定义配置了的 [fluentd](http://www.fluentd.org/) 作为节点上的 logging-agent。
+
+## 在 sidecar 容器中配置 logging-agent
+
+您可以按照如下方式使用 sidecar 容器，以收集日志：
+* sidecar 容器跟踪应用程序的日志文件，并输出到 sidecar 容器自己的 stdout
+* sidecar 容器运行一个 logging-agent，追踪应用程序的日志文件，并发送到日志后端
+
+### sidecar输出到stdout
+
+![Kubernetes教程_集群级别的日志_从sidecar输出到stdout](./cluster.assets/logging-with-streaming-sidecar.png)
+
+使用 sidecar 容器将应用程序的日志输出到 sidecar 容器自己的 `stdout` 和 `stderr` 之后，您可以直接利用已经在集群上运行的 kubelet 以及节点级别的 logging-agent 进一步将日志发送到日志后端。此时 sidecar 容器可以从日志文件读取、socket读取或者 journald 读取日志内容，其输出则是 sidecar 容器自己的 `stdout` 和 `stderr`。
+
+使用这种方法：
+* 您只需要对那些不能将日志输出到 `stdout` 和 `stderr` 的应用程序进行特殊配置即可，那些已经可以将日志输出到 `stdout` 和 `stderr` 的应用程序，则可以直接利用节点级别的 logging-agent。
+* 由于重定向日志的逻辑非常简单，这种做法所带来的系统开销也是非常小的。
+* 此外，`stdout` 和 `stderr` 由 kubelet 处理，您还可以直接使用支持 apiserver 的 kubernetes 管理工具来查看日志，例如 `kubectl logs`、Kubernetes Dashboard 或 Kuboard 的日志查看界面。
+
+以下面的例子为例，该 Pod 中的容器将日志记录到两个日志文件中，且两个日志文件的日志格式不一样。YAML 文件如下所示：
+
+``` yaml
+apiVersion: v1
+kind: Pod
+metadata:
+  name: counter
+spec:
+  containers:
+  - name: count
+    image: busybox
+    args:
+    - /bin/sh
+    - -c
+    - >
+      i=0;
+      while true;
+      do
+        echo "$i: $(date)" >> /var/log/1.log;
+        echo "$(date) INFO $i" >> /var/log/2.log;
+        i=$((i+1));
+        sleep 1;
+      done
+    volumeMounts:
+    - name: varlog
+      mountPath: /var/log
+  volumes:
+  - name: varlog
+    emptyDir: {}
+```
+
+如果将两个日志文件中完全不同的日志格式都通过一个 sidecar 容器重定向到其 `stdout` 中，最终的结果将非常混乱，你很难正确地对日志内容进行合适的处理。此时，可以考虑用两个 sidecar 容器，每个 sidecar 容器都追踪其中一个日志文件，并将日志重定向到各自的 `stdout` 中。
+
+<<< @/.vuepress/public/statics/learning/logs/counter-sidecar-pod.yaml
+
+* 执行如下命令以运行该 Pod
+
+  ``` sh
+  kubectl apply -f https://kuboard.cn/statics/learning/logs/counter-sidecar-pod.yaml
+  ```
+
+* 此时，您可以通过不同的两个容器的 `stdout` 查看到想要追踪的日志文件：
+  
+  查看第一个日志内容
+  ``` sh
+  #执行命令
+  kubectl logs conter count-log-1
+  # 输出结果如下
+  0: Mon Jan  1 00:00:00 UTC 2001
+  1: Mon Jan  1 00:00:01 UTC 2001
+  2: Mon Jan  1 00:00:02 UTC 2001
+  ...
+  ```
+  查看第二个日志内容
+  ``` sh
+  # 执行命令
+  kubectl logs counter count-log-2
+  # 输出结果如下
+  Mon Jan  1 00:00:00 UTC 2001 INFO 0
+  Mon Jan  1 00:00:01 UTC 2001 INFO 1
+  Mon Jan  1 00:00:02 UTC 2001 INFO 2
+  ...
+  ```
+
+此时，在无需额外配置的情况下，节点级别的 logging-agent 将自动把这些容器标准输出中的内容发送到您的日志后端。如果有必要，您也可以按照容器的不同使用不同的日志解析方法配置节点级别的 logging-agent。
+
+::: tip 注意
+尽管 `logging-agent` sidecar 容器只消耗很少的 CPU 和内存（大概千分之几个 CPU 内核和几兆内存的样子），将日志写入文件，然后重定向到 `stdout`，此时再被容器引擎写入到 `/var/log/containers` 目录，这种做法仍然会消耗双倍的磁盘空间。如果您的应用程序将日志写入一个单一的文件中，更好的做法是使用 `/dev/stdout` 作为写入日志的目标，而不是使用 sidecar 容器重定向日志的方法
+:::
+
+如果应用程序不能自行轮转日志文件，Sidecar 容器也可以用来轮转日志文件。例如，在一个 sidecar 容器中周期性的运行 logrotate 程序。不过，更好的办法是，直接将日志输出到 `stdout` 和 `stderr`，把日志轮转和日志保存的策略配置，交给 kubelet。
+
+### sidecar容器中执行 logging-agent
+
+![Kubernetes教程_集群级别的日志_从sidecar使用logging-agent](./cluster.assets/logging-with-sidecar-agent.png)
+
+如果节点级别的 logging-agent 不满足您的需要，您还可以考虑创建一个 sidecar 容器，并直接在该容器中运行一个为您的应用程序特别定制的 logging-agent。
+
+::: tip 注意
+在 sidecar 容器中使用 logging-agent 可能消耗比较多的资源。此外，您也不能够使用 `kubectl logs `命令或者 Kuboard 的命令行终端查看这些日志，因为这个已经不受 kubelet 控制了。
+:::
+
+下面的例子中，使用了 [Stackdriver](https://kubernetes.io/docs/tasks/debug-application-cluster/logging-stackdriver/)，并配合 fluentd 作为 logging-agent。本例子提供了两个配置文件：
+* 第一个文件中包含了用于配置 fluentd 的内容
+  ``` yaml
+  apiVersion: v1
+  kind: ConfigMap
+  metadata:
+    name: fluentd-config
+  data:
+    fluentd.conf: |
+      <source>
+        type tail
+        format none
+        path /var/log/1.log
+        pos_file /var/log/1.log.pos
+        tag count.format1
+      </source>
+
+      <source>
+        type tail
+        format none
+        path /var/log/2.log
+        pos_file /var/log/2.log.pos
+        tag count.format2
+      </source>
+
+      <match **>
+        type google_cloud
+      </match>
+  ```
+* 第二个文件是一个使用 fluentd 作为 sidecar 容器的 Pod。该 Pod 挂载了上面的 ConfigMap 作为一个数据卷，fluentd 从该数据卷读取配置：
+  ``` yaml
+  apiVersion: v1
+  kind: Pod
+  metadata:
+    name: counter
+  spec:
+    containers:
+    - name: count
+      image: busybox
+      args:
+      - /bin/sh
+      - -c
+      - >
+        i=0;
+        while true;
+        do
+          echo "$i: $(date)" >> /var/log/1.log;
+          echo "$(date) INFO $i" >> /var/log/2.log;
+          i=$((i+1));
+          sleep 1;
+        done
+      volumeMounts:
+      - name: varlog
+        mountPath: /var/log
+    - name: count-agent
+      image: k8s.gcr.io/fluentd-gcp:1.30
+      env:
+      - name: FLUENTD_ARGS
+        value: -c /etc/fluentd-config/fluentd.conf
+      volumeMounts:
+      - name: varlog
+        mountPath: /var/log
+      - name: config-volume
+        mountPath: /etc/fluentd-config
+    volumes:
+    - name: varlog
+      emptyDir: {}
+    - name: config-volume
+      configMap:
+        name: fluentd-config
+  ```
+
+::: tip
+这个例子中使用了 Stackdriver 和 fluentd-gcp 容器，都依赖于 Google Computing Platform。实际在您的使用过程中，应该替换成您所需要的 logging-agent。
+:::
+
+## 直接从应用程序容器发送日志到后端
+
+![Kubernetes教程_集群级别的日志_从sidecar发送日志到后端](./cluster.assets/logging-from-application.png)
+
+要实现集群级别的日志，您也可以直接在每一个应用程序中将日志发送到日志后端，这种做法是 kubernetes 范围之外的，按照您通常的日志处理办法去做就可以了。
diff --git a/overview/README.md b/overview/README.md
index 5cca57c..fcd3b09 100644
--- a/overview/README.md
+++ b/overview/README.md
@@ -6,7 +6,7 @@ meta:
     content: Kubernetes管理界面,K8S管理界面,Kubernetes Dashboard
 ---
 
-## Kuboard简介
+# Kuboard简介
 
 <div style="background-color: #0063dc;">
 <div style="max-width: 363px; margin: auto;">
diff --git a/overview/k8s-core-concepts.md b/overview/k8s-core-concepts.md
index 79f34f9..b8c0ddc 100644
--- a/overview/k8s-core-concepts.md
+++ b/overview/k8s-core-concepts.md
@@ -1,5 +1,5 @@
 ---
-description: Kubernetes教程_以gif动图的形式形象的描述Kubernetes核心概念_本文将会简单介绍Kubernetes的核心概念_因为这些定义可以在Kubernetes的文档中找到_所以文章也会避免用大段的枯燥的文字介绍。相反，我们会使用一些图表（其中一些是动画）和示例来解释这些概念。我们发现一些概念（比如Service）如果没有图表的辅助就很难全面地理解。在合适的地方我们也会提供Kubernetes文档的链接以便读者深入学习。
+description: Kubernetes教程_以gif动图的形式形象的描述Kubernetes核心概念_本文将会简单介绍Kubernetes的核心概念_因为这些定义可以在Kubernetes的文档中找到_所以文章也会避免用大段的枯燥的文字介绍。相反，我们会使用一些图表（其中一些是动画）和示例来解释这些概念。
 ---
 
 # 十分钟带你理解Kubernetes核心概念
diff --git a/overview/why-kuboard.md b/overview/why-kuboard.md
index 0912c7e..41432fb 100644
--- a/overview/why-kuboard.md
+++ b/overview/why-kuboard.md
@@ -6,7 +6,7 @@ meta:
     content: Kubernetes管理界面,K8S教程,Kubernetes教程,K8S管理界面
 ---
 
-## 为什么选择Kuboard
+# 为什么选择Kuboard
 
 Kubernetes 已然是当下容器编排领域事实上的标准，各大云服务商都急于推出 Kubernetes 服务，互联网公司也纷纷跟进，将自己的应用容器化，并使用 Kubernetes 编排。