From 932fb96179592ede5d90b5bbc22f067ef6677135 Mon Sep 17 00:00:00 2001
From: roc <roc@imroc.cc>
Date: Fri, 19 Apr 2024 15:45:54 +0800
Subject: [PATCH] update at 2024-04-19 15:45:54

---
 codeblock/graceful/update-strategy.yaml       | 36 +++++++++++++++++++
 .../graceful-shutdown/update-strategy.md      | 12 +++++++
 content/best-practices/sidebars.ts            |  1 +
 3 files changed, 49 insertions(+)
 create mode 100644 codeblock/graceful/update-strategy.yaml
 create mode 100644 content/best-practices/graceful-shutdown/update-strategy.md

diff --git a/codeblock/graceful/update-strategy.yaml b/codeblock/graceful/update-strategy.yaml
new file mode 100644
index 0000000..cf7fa54
--- /dev/null
+++ b/codeblock/graceful/update-strategy.yaml
@@ -0,0 +1,36 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: nginx
+spec:
+  replicas: 1
+  selector:
+    matchLabels:
+      app: nginx
+  strategy:
+    # highlight-start
+    type: RollingUpdate
+    rollingUpdate: # 单个串行升级，等新副本 ready 后才开始销毁旧副本
+      maxUnavailable: 0
+      maxSurge: 1
+    # highlight-end
+  template:
+    metadata:
+      labels:
+        app: nginx
+    spec:
+      containers:
+        - name: nginx
+          image: nginx:latest
+          startupProbe:
+            httpGet:
+              path: /
+              port: 80
+            # highlight-next-line
+            successThreshold: 5 # 新副本启动时，连续探测成功多次后才交给 readinessProbe 探测
+          readinessProbe:
+            httpGet:
+              path: /
+              port: 80
+            # highlight-next-line
+            successThreshold: 1 # 运行过程中探测 1 次成功就认为 ready，可在抖动导致异常后快速恢复服务
diff --git a/content/best-practices/graceful-shutdown/update-strategy.md b/content/best-practices/graceful-shutdown/update-strategy.md
new file mode 100644
index 0000000..9799d57
--- /dev/null
+++ b/content/best-practices/graceful-shutdown/update-strategy.md
@@ -0,0 +1,12 @@
+# 配置保守的更新策略
+
+## 保守更新策略
+
+如果对稳定性要求较高，可以设置比较保守的滚动更新策略：
+1. 避免在滚动时可以正常处理请求的 Pod 数量减少导致部分请求因后端 Pod 处理不过来而异常。
+2. 减缓发版速度，避免新版应用引入难以发现的问题快速扩散，方便发现后及时回滚恢复。
+3. 新副本启动时，多给应用一些时间进行准备，避免某些应用虽然探测接口返回就绪，但实际处理能力还没跟上，过早转发请求过来可能导致异常。
+
+## 配置示例
+
+<FileBlock file="graceful/update-strategy.yaml" showLineNumbers />
diff --git a/content/best-practices/sidebars.ts b/content/best-practices/sidebars.ts
index 95eb6bb..db823c0 100644
--- a/content/best-practices/sidebars.ts
+++ b/content/best-practices/sidebars.ts
@@ -18,6 +18,7 @@ const sidebars: SidebarsConfig = {
         'graceful-shutdown/why-cannot-receive-sigterm',
         'graceful-shutdown/propagating-signals-in-shell',
         'graceful-shutdown/use-prestop',
+        'graceful-shutdown/update-strategy',
         'graceful-shutdown/persistent-connection',
         'graceful-shutdown/lb-to-pod-directly',
       ],