Mysql-proxy
參考：https://segmentfault.com/q/1010000000394160
情景分析：首先您需要正在使用UCloud雲主機（uhoust）以及雲數據庫（udb）。
鑒於udb無外網ip不能直接訪問，可利用mysql-proxy將udb跳轉到雲主機的某一端口上進行訪問，方便客戶操作。
1. 安裝mysql-proxy
[root@localhost ~]# yum install mysql-proxy
查看版本：
[root@localhost ~]# mysql-proxy -V
mysql-proxy 0.8.5
chassis: 0.8.5
glib2: 2.28.8
libevent: 1.4.13-stable
LUA: Lua 5.1.4
package.path: /usr/lib64/mysql-proxy/lua/?.lua
package.cpath: /usr/lib64/mysql-proxy/lua/?.so
-- modules
proxy: 0.8.5
2. 配置mysql-proxy
配置mysql-proxy
大家也可以mysql-proxy -help-all查看它的幫助選項
此服務默認缺省端口為4040，也就是通過訪問4040就能訪問目標3306
但是新版mysql-proxy已經將4040改為了3307，默認3307。
可以直接命令開啟服務，不過推薦使用配置文件，步驟如下：
[root@localhost ~]# vim /etc/mysql-proxy.cnf [mysql-proxy] daemon = true pid-file = /var/run/mysql-proxy.pid log-file = /var/log/mysql-proxy.log log-level = debug max-open-files = 1024 plugins = admin,proxy user = mysql-proxy # #Proxy Configuration proxy-address = 0.0.0.0:3307 # 這里我們注釋這一行，代理端口就默認改為了4040，也可以不改，后面連接端口就改為3307就可以了。 proxy-backend-addresses = 10.41.1.2 # 內網的數據庫地址，默認3306端口 #proxy-read-only-backend-addresses = #proxy-lua-script = #proxy-skip-profiling = true # # Admin Configuration # admin-address = 0.0.0.0:4041 # 監聽端口是4041 admin-lua-script = /usr/lib64/mysql-proxy/lua/admin.lua admin-username = root # 數據庫用戶名 admin-password = rootdbpassword # 數據庫密碼
寫好配置文件保存后需要改變權限，以上配置是由mysql-proxy自動生成的，所以權限已經是660了，可以查看一下：
[root@localhost ~]# ll /etc/mysql-proxy.cnf -rw-rw---- 1 root root 519 Aug 10 2016 /etc/mysql-proxy.cnf
如果不是，用以下命令修改。
[root@localhost ~]# chmod 0660 /etc/mysql-proxy.cnf
3. 啟動進程
[root@localhost ~]# mysql-proxy --defaults-file=/etc/mysql-proxy.cnf
查看是否啟動成功：
[root@localhost ~]# netstat -anplut|grep mysql-proxy tcp 0 0 0.0.0.0:4041 0.0.0.0:* LISTEN 28110/mysql-proxy tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 28110/mysql-proxy
若關閉kill命令把程序終止
4. 打開防火牆端口
需要在UCloud管理控制台中 打開雲主機3307端口。
5. 測試
在外網環境，另一台主機：
[root@localhost ~]# mysql -u root -p -P3307 -h host
host為uhoust外網ip
6、錯誤分析
錯誤1、
[root@localhost ~]# mysql-proxy --defaults-file=/etc/mysql-proxy.cnf 2018-12-28 20:49:35: (critical) Key file contains key 'daemon' which has value that cannot be interpreted. 2018-12-28 20:49:35: (message) Initiating shutdown, requested from mysql-proxy-cli.c:367 2018-12-28 20:49:35: (message) shutting down normally, exit code is: 1
配置不對，可能用了網上的配置比如：
[mysql-proxy] admin-username=root #admin用戶名 admin-password=123fsck #admin密碼 admin-lua-script=/usr/lib64/mysql-proxy/lua/admin.lua #lua位置，參見上面的版本信息 daemon=true # mysql-proxy以守護進程方式運行 keepalive=true #保持連接啟動進程會有2個, 一號進程用來監視二號進程 proxy-backend-addresses=10.6.X.XX #目標地址，udb內網地址，默認端口3306 log-file=/var/log/mysql-proxy.log log-level=debug
用這段配置就會報上述錯誤，版本不一樣。新版mysql-proxy會自動生成/etc/mysql-proxy.cnf配置，我們修改相應字段就好了。如上述步驟2。
錯誤2、
[root@localhost ~]# mysql -hxx.xx.xx.xx -P4041 -uroot -p
Enter password: Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 11690111 Server version: 5.6.20-ucloudrel1-log Source distribution Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show databases; ERROR 1105 (07000): use 'SELECT * FROM help' to see the supported commands mysql> use mysql; ERROR 1105 (07000): [admin] we only handle text-based queries (COM_QUERY) mysql> select * from mysql.user; ERROR 1105 (07000): use 'SELECT * FROM help' to see the supported commands
mysql> select * from help
-> ;
+------------------------+------------------------------------+
| command | description |
+------------------------+------------------------------------+
| SELECT * FROM help | shows this help |
| SELECT * FROM backends | lists the backends and their state |
+------------------------+------------------------------------+
2 rows in set (0.14 sec)
mysql> select * from backends
-> ;
+-------------+-------------------+---------+------+------+-------------------+
| backend_ndx | address | state | type | uuid | connected_clients |
+-------------+-------------------+---------+------+------+-------------------+
| 1 | 10.41.1.2:3306 | unknown | rw | NULL | 0 |
+-------------+-------------------+---------+------+------+-------------------+
1 row in set (0.18 sec)
這是因為一開始我們用了這樣的配置：
[root@localhost ~]# vim /etc/mysql-proxy.cnf [mysql-proxy] daemon = true pid-file = /var/run/mysql-proxy.pid log-file = /var/log/mysql-proxy.log log-level = debug max-open-files = 1024 plugins = admin,proxy user = mysql-proxy # #Proxy Configuration proxy-address = 0.0.0.0:3307 proxy-backend-addresses = 10.41.1.2 #proxy-read-only-backend-addresses = #proxy-lua-script = #proxy-skip-profiling = true # # Admin Configuration # admin-address = 0.0.0.0:4041 admin-lua-script = /usr/lib64/mysql-proxy/lua/admin.lua admin-username = root admin-password = rootdbpassword
以上兩點不一樣，此時我們查看mysql-proxy進程，會發現
[root@localhost ~]# netstat -anplut|grep mysql-proxy tcp 0 0 0.0.0.0:4041 0.0.0.0:* LISTEN 28110/mysql-proxy tcp 0 0 0.0.0.0:3307 0.0.0.0:* LISTEN 28110/mysql-proxy
這里，這個配置是新版的mysql-proxy配置，如上述所示，此時mysql-proxy的代理端口是3307，監聽端口是4041，但是你的進程連接的卻是這個監聽端口，所以會報上述錯誤。此時，我們只需要將連接端口改為3307就可以了。（老版mysql-proxy的端口是4040.）
[root@localhost ~]# mysql -hxx.xx.xx.xx -P4041 -uroot -p
改為===》
[root@localhost ~]# mysql -hxx.xx.xx.xx -P3307 -uroot -p
錯誤就解決了。