添加自动判断主从

MySQL自动切换主从/switch_master_slave.sh

@@ -10,12 +10,21 @@ MYSQL_PORT=3306               # MySQL端口
 MYSQL_REPL_USER="repl"
 MYSQL_REPL_PASSWD="Unary@2023"
 
-# TODO(MH:)获取当前主从关系
-get_current_roles() {
-    if [ -f "$IDENTIFIER_FILE" ]; then
-        CURRENT_ROLE=$(cat "$IDENTIFIER_FILE")
+# 获取当前主从关系
+pre_check() {
+    MASTER_STATUS=$(mysql -h$MASTER_HOST -u$MYSQL_USER -p$MYSQL_PASSWORD -P$MYSQL_PORT -e "show slave status\\G;"|grep -E "Slave_IO_Running: Yes|Slave_SQL_Running: Yes|Seconds_Behind_Master: 0"|wc -l)
+    SLAVE_STATUS=$(mysql -h$SLAVE_HOST -u$MYSQL_USER -p$MYSQL_PASSWORD -P$MYSQL_PORT -e "show slave status\\G;"|grep -E "Slave_IO_Running: Yes|Slave_SQL_Running: Yes|Seconds_Behind_Master: 0"|wc -l)
+    if [ "$MASTER_STATUS" -eq 0 ] && [ "$SLAVE_STATUS" -eq 3 ]; then
+        echo "$MASTER_HOST 是主节点，即将切换为 $SLAVE_HOST"
+    elif [ "$MASTER_STATUS" -eq 3 ] && [ "$SLAVE_STATUS" -eq 0 ]; then
+        echo "$SLAVE_HOST 是主节点，即将切换为 $MASTER_HOST"
+        # 交换主从
+        new_master=$MASTER_HOST
+        MASTER_HOST=$SLAVE_HOST
+        SLAVE_HOST=$new_master
     else
-        CURRENT_ROLE="unknown"
+        echo "当前不是主从集群，请确认后主从状态是否正常"
+        exit 1
     fi
 }
 
@@ -69,17 +78,19 @@ check_replication_status() {
     REPLICATION_STATUS=$(mysql -h$MASTER_HOST -u$MYSQL_USER -p$MYSQL_PASSWORD -P$MYSQL_PORT -e "show slave status\\G;"|grep -E "Slave_IO_Running: Yes|Slave_SQL_Running: Yes|Seconds_Behind_Master: 0"|wc -l)
     
     # 判断是否修改成功了
-    if [ "$off_number" != "3" ]; then
+    if [ "$REPLICATION_STATUS" != "3" ]; then
         echo "主从切换异常，请人工确认！！"
         exit 1
     fi
-    echo "主从切换成功！"
+    echo "主从切换成功！当前 $SLAVE_HOST 是主节点"
 }
 
 # 主函数
 main() {
-    #get_current_roles
+    # 预检测
+    pre_check
     # 将主节点设置为只读
+    echo  $MASTER_HOST
     set_master_redonly
     # 停止从节点，并关闭只读
     set_slaver_status