应用客户端初始化mysql router后，服务无法启动

郑全

问题现象：
   systemctl start mysqlrouter
   一直到超时，不成功


问题分析：
    systemctl status mysqlrouter
    状态为activing
   mysql router 无法使用


   检查配置文件，找到router的日志文件
     [root@npzp7jab ~]# rpm -qa|grep routermysql-router-community-8.4.8-1.el7.x86_64     [root@npzp7jab ~]# rpm -qc mysql-router-community-8.4.8-1.el7.x86_64
     /etc/logrotate.d/mysqlrouter
     /etc/mysqlrouter/mysqlrouter.conf


[root@npzp7jab ~]# grep -i log /etc/mysqlrouter/mysqlrouter.conf
logging_folder=/etc/mysqlrouter/log

[root@npzp7jab ~]# ls -ltr /etc/mysqlrouter/log/mysqlrouter.log
-rw-r--r-- 1 mysqlrouter mysqlrouter 180286 Apr  8 08:41 /etc/mysqlrouter/log/mysqlrouter.log


检查日志文件：


tail -1000 /etc/mysqlrouter/log/mysqlrouter.log


2026-04-08 16:28:43 main SYSTEM [7f14038df880] Starting 'MySQL Router', version: 8.4.8 (MySQL Community - GPL)
2026-04-08 16:28:43 io INFO [7f14038df880] starting 2 io-threads, using backend 'linux_epoll'
2026-04-08 16:28:43 http_server INFO [7f14038df880] listening on 0.0.0.0:8443
2026-04-08 16:28:43 metadata_cache_plugin INFO [7f13e7fff700] Starting Metadata Cache
2026-04-08 16:28:43 metadata_cache INFO [7f13e7fff700] Connections using ssl_mode 'PREFERRED'2026-04-08 16:28:43 metadata_cache INFO [7f13fc482700] Starting metadata cache refresh thread2026-04-08 16:28:43 routing_plugin INFO [7f13e57fa700] [routing:bootstrap_ro] 'router_require_enforce=1', but neither 'client_ssl_ca' nor 'client_ssl_cadir' are set. MySQL account with ATTRIBUTE '{ "router_require": { "x509": true } }' will fail to auth.2026-04-08 16:28:43 routing INFO [7f13e57fa700] [routing:bootstrap_ro] started: routing strategy = round-robin-with-fallback2026-04-08 16:28:43 routing INFO [7f13e57fa700] Start accepting connections for routing routing:bootstrap_ro listening on '0.0.0.0:6447'2026-04-08 16:28:43 routing_plugin INFO [7f13c3fff700] [routing:bootstrap_rw_split] 'router_require_enforce=1', but neither 'client_ssl_ca' nor 'client_ssl_cadir' are set. MySQL account with ATTRIBUTE '{ "router_require": { "x509": true } }' will fail to auth.2026-04-08 16:28:43 routing INFO [7f13c3fff700] [routing:bootstrap_rw_split] started: routing strategy = round-robin2026-04-08 16:28:43 routing INFO [7f13c3fff700] Start accepting connections for routing routing:bootstrap_rw_split listening on '0.0.0.0:6450'2026-04-08 16:28:43 routing INFO [7f13c37fe700] [routing:bootstrap_x_ro] started: routing strategy = round-robin-with-fallback2026-04-08 16:28:43 routing INFO [7f13c37fe700] Start accepting connections for routing routing:bootstrap_x_ro listening on '0.0.0.0:6449'2026-04-08 16:28:43 routing_plugin INFO [7f13e4ff9700] [routing:bootstrap_rw] 'router_require_enforce=1', but neither 'client_ssl_ca' nor 'client_ssl_cadir' are set. MySQL account with ATTRIBUTE '{ "router_require": { "x509": true } }' will fail to auth.2026-04-08 16:28:43 routing INFO [7f13e4ff9700] [routing:bootstrap_rw] started: routing strategy = first-available2026-04-08 16:28:43 routing INFO [7f13e4ff9700] Start accepting connections for routing routing:bootstrap_rw listening on '0.0.0.0:6446'2026-04-08 16:28:43 routing INFO [7f13c2ffd700] [routing:bootstrap_x_rw] started: routing strategy = first-available2026-04-08 16:28:43 routing INFO [7f13c2ffd700] Start accepting connections for routing routing:bootstrap_x_rw listening on '0.0.0.0:6448'2026-04-08 16:28:43 metadata_cache WARNING [7f13fc482700] Failed connecting with Metadata Server mysql-node3:3306: Unknown MySQL server host 'mysql-node3' (-2) (2005)2026-04-08 16:28:43 metadata_cache WARNING [7f13fc482700] Failed connecting with Metadata Server mysql-node2:3306: Unknown MySQL server host 'mysql-node2' (-2) (2005)2026-04-08 16:28:44 metadata_cache WARNING [7f13fc482700] Failed connecting with Metadata Server mysql-node1:3306: Unknown MySQL server host 'mysql-node1' (-2) (2005)2026-04-08 16:28:44 metadata_cache ERROR [7f13fc482700] Failed fetching metadata from any of the 3 metadata servers.2026-04-08 16:30:14 main SYSTEM [7f13ffd95700] Stopping 'MySQL Router', version: 8.4.8 (MySQL Community - GPL), reason: REQUESTED (Signal Terminated sent by UID: 0 and PID: 1)2026-04-08 16:30:14 routing INFO [7f13e57fa700] Stop accepting connections for routing routing:bootstrap_ro listening on 0.0.0.0:64472026-04-08 16:30:14 routing INFO [7f13c3fff700] Stop accepting connections for routing routing:bootstrap_rw_split listening on 0.0.0.0:64502026-04-08 16:30:14 routing INFO [7f13c37fe700] Stop accepting connections for routing routing:bootstrap_x_ro listening on 0.0.0.0:64492026-04-08 16:30:14 routing INFO [7f13c2ffd700] Stop accepting connections for routing routing:bootstrap_x_rw listening on 0.0.0.0:64482026-04-08 16:30:14 routing INFO [7f13e4ff9700] Stop accepting connections for routing routing:bootstrap_rw listening on 0.0.0.0:64462026-04-08 16:30:14 routing INFO [7f13c2ffd700] [routing:bootstrap_x_rw] stopped2026-04-08 16:30:14 routing INFO [7f13e4ff9700] [routing:bootstrap_rw] stopped2026-04-08 16:30:14 routing INFO [7f13c37fe700] [routing:bootstrap_x_ro] stopped2026-04-08 16:30:14 routing INFO [7f13c3fff700] [routing:bootstrap_rw_split] stopped2026-04-08 16:30:14 routing INFO [7f13e57fa700] [routing:bootstrap_ro] stopped2026-04-08 16:30:14 main SYSTEM [7f7aa1789880] Starting 'MySQL Router', version: 8.4.8 (MySQL Community - GPL)2026-04-08 16:30:14 io INFO [7f7aa1789880] starting 2 io-threads, using backend 'linux_epoll'2026-04-08 16:30:14 http_server INFO [7f7aa1789880] listening on 0.0.0.0:84432026-04-08 16:30:14 metadata_cache_plugin INFO [7f7a95ffb700] Starting Metadata Cache2026-04-08 16:30:14 metadata_cache INFO [7f7a95ffb700] Connections using ssl_mode 'PREFERRED'2026-04-08 16:30:14 metadata_cache INFO [7f7a9c330700] Starting metadata cache refresh thread2026-04-08 16:30:14 routing_plugin INFO [7f7a76ffd700] [routing:bootstrap_ro] 'router_require_enforce=1', but neither 'client_ssl_ca' nor 'client_ssl_cadir' are set. MySQL account with ATTRIBUTE '{ "router_require": { "x509": true } }' will fail to auth.2026-04-08 16:30:14 routing_plugin INFO [7f7a767fc700] [routing:bootstrap_rw] 'router_require_enforce=1', but neither 'client_ssl_ca' nor 'client_ssl_cadir' are set. MySQL account with ATTRIBUTE '{ "router_require": { "x509": true } }' will fail to auth.2026-04-08 16:30:14 routing INFO [7f7a76ffd700] [routing:bootstrap_ro] started: routing strategy = round-robin-with-fallback
2026-04-08 16:30:14 routing INFO [7f7a76ffd700] Start accepting connections for routing routing:bootstrap_ro listening on '0.0.0.0:6447'
2026-04-08 16:30:14 routing INFO [7f7a767fc700] [routing:bootstrap_rw] started: routing strategy = first-available
2026-04-08 16:30:14 routing INFO [7f7a767fc700] Start accepting connections for routing routing:bootstrap_rw listening on '0.0.0.0:6446'
2026-04-08 16:30:14 routing_plugin INFO [7f7a75ffb700] [routing:bootstrap_rw_split] 'router_require_enforce=1', but neither 'client_ssl_ca' nor 'client_ssl_cadir' are set. MySQL account with ATTRIBUTE '{ "router_require": { "x509": true } }' will fail to auth.
2026-04-08 16:30:14 routing INFO [7f7a75ffb700] [routing:bootstrap_rw_split] started: routing strategy = round-robin
2026-04-08 16:30:14 routing INFO [7f7a75ffb700] Start accepting connections for routing routing:bootstrap_rw_split listening on '0.0.0.0:6450'
2026-04-08 16:30:14 routing INFO [7f7a757fa700] [routing:bootstrap_x_ro] started: routing strategy = round-robin-with-fallback
2026-04-08 16:30:14 routing INFO [7f7a757fa700] Start accepting connections for routing routing:bootstrap_x_ro listening on '0.0.0.0:6449'
2026-04-08 16:30:14 routing INFO [7f7a74ff9700] [routing:bootstrap_x_rw] started: routing strategy = first-available
2026-04-08 16:30:14 routing INFO [7f7a74ff9700] Start accepting connections for routing routing:bootstrap_x_rw listening on '0.0.0.0:6448'
2026-04-08 16:30:14 metadata_cache WARNING [7f7a9c330700] Failed connecting with Metadata Server mysql-node3:3306: Unknown MySQL server host 'mysql-node3' (-2) (2005)
2026-04-08 16:30:14 metadata_cache WARNING [7f7a9c330700] Failed connecting with Metadata Server mysql-node2:3306: Unknown MySQL server host 'mysql-node2' (-2) (2005)


发现是数据库的主机名无法解析


增加对数据库节点的解析后，再看，已经正常
cat  /etc/hosts
xxxx mysql-node1
xxx  mysql-node2
xxxx mysql-node3


tail -10 /etc/mysqlrouter/log/mysqlrouter.log


2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700] Using unreachable_quorum_allowed_traffic='none'
2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700] Using read_only_targets='secondaries'
2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700] Potential changes detected in cluster after metadata refresh (view_id=0)
2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700] Metadata for cluster 'testcluster' has 3 member(s), single-primary:
2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700]     mysql-node3:3306 / 33060 - mode=RO
2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700]     mysql-node2:3306 / 33060 - mode=RO
2026-04-08 08:41:35 metadata_cache INFO [7f28501e1700]     mysql-node1:3306 / 33060 - mode=RW
2026-04-08 08:41:36 metadata_cache INFO [7f28501e1700] Connected with metadata server running on mysql-node1:3306

问题消除。

[root@npzp7jab ~]# systemctl status mysqlrouter
● mysqlrouter.service
- MySQL Router   Loaded: loaded (/usr/lib/systemd/system/mysqlrouter.service; enabled; vendor preset: disabled)   
Active: active (running) since Wed 2026-04-08 08:41:35 UTC; 3h 53min ago
Main PID: 30327 (mysqlrouter)   
Status: "running"   
CGroup: /system.slice/mysqlrouter.service           
└─30327 /usr/bin/mysqlrouter
Apr 08 08:40:30 npzp7jab.vm systemd[1]: Starting MySQL Router...
Apr 08 08:41:35 npzp7jab.vm systemd[1]: Started MySQL Router.