Oracle/DB2/Postgresql/Mysql/Hadoop/Greenplum/Postgres-xl/Mongodb
分类: LINUX
2012-03-20 18:45:33
使用Apache和Resin进行组合时,如果Resin关闭或中断的时会出现如下的HTTP 503错误:
Service Temporarily Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
造成这个错误的原因是因为Resin无法启动,可以单独访问resin(如8080端口)查看具体的错误。
我这里要说的是,在Resin和Apache都非常非常正常的情况下,间歇性的出现上述错误,也就是说不是一直有,而是偶尔出现这个错误,刷新下页面就好了。这个问题非常郁闷,后来在resin的bug报告中(见参考资料)竟然发现了解决的办法:
The important configuration are load-balance-socket-timeout, socket-timeout, load-balance-idle-time and keepalive-timeout. The two load-balance-* configure mod_caucho. socket-timeout and keepalive-timeout configure the Resin side.
load-balance-socket-timeout needs to be large enough to handle any server-side processing delays before the first data.
socket-timeout and keepalive-timeout need to be larger than load-balance-idle-time because they need to keep the connection open for a keepalive request.
For a diagram, see
也就是说,Resin在同Apache进行组合通讯的时候主要依靠四个参数:load-balance-socket-timeout, socket-timeout, load-balance-idle-time 和 keepalive-timeout,其中两个load-balance-*参数用来设置mod_caucho(就是与Apache组合的so文件),socket-timeout和keepalive-timeout用来设置Resin。至于参数数值的大小顺序依此是:load-balance-socket-timeout > socket-timeout 和 keepalive-timeout > load-balance-idle-time。上述四个参数的官方说明地址为:
那为什么会间歇性出现503错误呢?这个是因为resin默认的socket-timeout为65s,时间太短了,有些比较大的请求在这个时间之内还没有进行完。综合上面所说,参考的配置如下:
从此,这个世界清净了。
参考资料:
resin apache问题