api gateway 有时会报以下错误， 页面是404。 系统组件都处于正常运行状态。在强制刷新页面后重新访问又正常。

2019-06-20 19:45:37.209 ERROR 62049 --- [or-http-epoll-1] a.w.r.e.AbstractErrorWebExceptionHandler : [851db638] 500 Server Error for HTTP GET "/blade-desk/xxxx"

io.netty.channel.AbstractChannel$AnnotatedConnectException: syscall:getsockopt(..) failed: Connection refused: /172.28.17.65:8105
        at io.netty.channel.unix.Socket.finishConnect(..)(Unknown Source) ~[netty-transport-native-unix-common-4.1.34.Final.jar!/:4.1.34.Final]
Caused by: io.netty.channel.unix.Errors$NativeConnectException: syscall:getsockopt(..) failed: Connection refused
        ... 1 common frames omitted

2019-06-20 19:54:08.806 ERROR 62049 --- [or-http-epoll-3] a.w.r.e.AbstractErrorWebExceptionHandler : [322d09cc] 500 Server Error for HTTP GET "/blade-desk/xxxx"

io.netty.channel.AbstractChannel$AnnotatedConnectException: syscall:getsockopt(..) failed: Connection refused: /172.28.17.65:8105
        at io.netty.channel.unix.Socket.finishConnect(..)(Unknown Source) ~[netty-transport-native-unix-common-4.1.34.Final.jar!/:4.1.34.Final]
Caused by: io.netty.channel.unix.Errors$NativeConnectException: syscall:getsockopt(..) failed: Connection refused
        ... 1 common frames omitted

2019-06-21 13:28:24.879 ERROR 62049 --- [or-http-epoll-2] a.w.r.e.AbstractErrorWebExceptionHandler : [3faca1cc] 500 Server Error for HTTP GET "/blade-desk/xxx"

io.netty.channel.AbstractChannel$AnnotatedConnectException: syscall:getsockopt(..) failed: Connection refused: /172.28.17.65:8105
        at io.netty.channel.unix.Socket.finishConnect(..)(Unknown Source) ~[netty-transport-native-unix-common-4.1.34.Final.jar!/:4.1.34.Final]
Caused by: io.netty.channel.unix.Errors$NativeConnectException: syscall:getsockopt(..) failed: Connection refused
        ... 1 common frames omitted

2019-06-21 13:28:42.538 ERROR 62049 --- [or-http-epoll-4] a.w.r.e.AbstractErrorWebExceptionHandler : [825622a1] 500 Server Error for HTTP GET "/blade-desk/xxx

io.netty.channel.AbstractChannel$AnnotatedConnectException: syscall:getsockopt(..) failed: Connection refused: /172.28.17.65:8105
        at io.netty.channel.unix.Socket.finishConnect(..)(Unknown Source) ~[netty-transport-native-unix-common-4.1.34.Final.jar!/:4.1.34.Final]
Caused by: io.netty.channel.unix.Errors$NativeConnectException: syscall:getsockopt(..) failed: Connection refused
        ... 1 common frames omitted

2019-06-21 13:28:42.541 ERROR 62049 --- [or-http-epoll-1] a.w.r.e.AbstractErrorWebExceptionHandler : [d7190ee7] 500 Server Error for HTTP GET "/blade-desk/xxx"

io.netty.channel.AbstractChannel$AnnotatedConnectException: syscall:getsockopt(..) failed: Connection refused: /172.28.17.65:8105
        at io.netty.channel.unix.Socket.finishConnect(..)(Unknown Source) ~[netty-transport-native-unix-common-4.1.34.Final.jar!/:4.1.34.Final]
Caused by: io.netty.channel.unix.Errors$NativeConnectException: syscall:getsockopt(..) failed: Connection refused