## 模块 3: 在负载运行时升级 TiDB 集群
### 步骤 1. 设置 TiUP 镜像位置
+ 返回 [终端 1](ssh://monitor1-ssh#1)，运行 tiup 命令更改 TiUP 本地镜像至 v8.1.1。
```bash
tiup mirror set tidb-community-server-8.1.1-linux-amd64
```
```output
Successfully set mirror to /home/ec2-user/tidb-community-server-8.1.1-linux-amd64
```
### 步骤 2. 升级你的 TiDB 集群
+ 运行 `tiup` 命令将 TiDB 集群从 v7.5.4 升级至 v8.1.1。在升级进行时，切换到 [终端 2](ssh://monitor1-ssh#2) 和 [终端 3](ssh://monitor1-ssh#3)。
```bash
tiup cluster upgrade tidb-demo 8.1.1 --yes
```
```output
Before the upgrade, it is recommended to read the upgrade guide at https://docs.tidb.io/tidb/stable/upgrade-tidb-using-tiup and finish the preparation steps.
This operation will upgrade tidb v7.5.4 cluster tidb-demo to v8.1.1:
will upgrade and restart component " pd" to "v8.1.1",
will upgrade and restart component " tikv" to "v8.1.1",
will upgrade and restart component " tidb" to "v8.1.1",
...
+ [ Serial ] - Download: component=grafana, version=v8.1.1, os=linux, arch=amd64
+ [ Serial ] - Download: component=tikv, version=v8.1.1, os=linux, arch=amd64
+ [ Serial ] - Download: component=tidb, version=v8.1.1, os=linux, arch=amd64
+ [ Serial ] - Download: component=prometheus, version=v8.1.1, os=linux, arch=amd64
+ [ Serial ] - Download: component=pd, version=v8.1.1, os=linux, arch=amd64
...
Upgrading component pd
Restarting instance 10.90.1.135:2379
Restart instance 10.90.1.135:2379 success
Restarting instance 10.90.2.182:2379
Restart instance 10.90.2.182:2379 success
Restarting instance 10.90.3.231:2379
Restart instance 10.90.3.231:2379 success
Upgrading component tikv
Evicting 11 leaders from store 10.90.1.55:20160...
Still waiting for 11 store leaders to transfer...
Still waiting for 11 store leaders to transfer...
...
Upgrading component tidb
Restarting instance 10.90.1.124:4000
Restart instance 10.90.1.124:4000 success
Restarting instance 10.90.2.122:4000
Restart instance 10.90.2.122:4000 success
...
```
### 步骤 3. 验证插入与查询负载未中断
+ 观察 [终端 2](ssh://monitor1-ssh#2) 和 [终端 3](ssh://monitor1-ssh#3)，确保示例应用程序连接和事务在升级期间从未中断。
+ 等待 [终端 1](ssh://monitor1-ssh#1) 中的升级命令完成，再进行下一步。
```output
...
Upgraded cluster `tidb-demo` successfully
```
### 步骤 4. 验证升级结果
+ 运行命令获取集群状态并确认集群版本是 8.1.1。
```bash
tiup cluster display tidb-demo
```
```output
Cluster type: tidb
Cluster name: tidb-demo
Cluster version: v8.1.1
Deploy user: ec2-user
SSH type: builtin
Dashboard URL: http://18.138.239.33:2379/dashboard
Grafana URL: http://10.90.4.8:3000
ID Role Host Ports OS/Arch Status Data Dir Deploy Dir
-- ---- ---- ----- ------- ------ -------- ----------
10.90.4.8:9093 alertmanager 10.90.4.8 9093/9094 linux/x86_64 Up /tidb-data/alertmanager-9093 /tidb-deploy/alertmanager-9093
10.90.4.8:3000 grafana 10.90.4.8 3000 linux/x86_64 Up - /tidb-deploy/grafana-3000
10.90.1.152:2379 pd 10.90.1.152 2379/2380 linux/x86_64 Up|L /tidb-data/pd-2379 /tidb-deploy/pd-2379
10.90.2.73:2379 pd 10.90.2.73 2379/2380 linux/x86_64 Up /tidb-data/pd-2379 /tidb-deploy/pd-2379
10.90.3.163:2379 pd 10.90.3.163 2379/2380 linux/x86_64 Up /tidb-data/pd-2379 /tidb-deploy/pd-2379
10.90.4.8:9090 prometheus 10.90.4.8 9090/12020 linux/x86_64 Up /tidb-data/prometheus-9090 /tidb-deploy/prometheus-9090
10.90.2.180:4000 tidb 10.90.2.180 4000/10080 linux/x86_64 Up - /tidb-deploy/tidb-4000
10.90.3.89:4000 tidb 10.90.3.89 4000/10080 linux/x86_64 Up - /tidb-deploy/tidb-4000
10.90.1.88:20160 tikv 10.90.1.88 20160/20180 linux/x86_64 Up /tidb-data/tikv-20160 /tidb-deploy/tikv-20160
10.90.2.20:20160 tikv 10.90.2.20 20160/20180 linux/x86_64 Up /tidb-data/tikv-20160 /tidb-deploy/tikv-20160
10.90.3.69:20160 tikv 10.90.3.69 20160/20180 linux/x86_64 Up /tidb-data/tikv-20160 /tidb-deploy/tikv-20160
10.90.1.60:6000 tiproxy 10.90.1.60 6000/3080 linux/x86_64 Up - /tidb-deploy/tiproxy-6000
Total nodes: 12
```
+ 按 Ctrl+C 停止 [终端 2](ssh://monitor1-ssh#2) 和 [终端 3](ssh://monitor1-ssh#3) 中的工作负载。