Apache httpd 错误“代理：ap_get_scoreboard_lb”与 ProxyPass

Question

我设置了 apache 来代理 tomcat，但是当我定位页面时出现以下错误。我有时会得到一个空白页或 503：

[错误]

[Mon Dec 03 04:58:16 2012] [error] proxy: ap_get_scoreboard_lb(2) failed in child 29611 for worker proxy:reverse
[Mon Dec 03 04:58:16 2012] [error] proxy: ap_get_scoreboard_lb(1) failed in child 29611 for worker https://localhost:8443/
[Mon Dec 03 04:58:16 2012] [error] proxy: ap_get_scoreboard_lb(0) failed in child 29611 for worker http://localhost:8080/

我在 vm 上配置了两个 vhost，如下所示：

[http 主机]

<VirtualHost *:80>
  ServerName www.mysite.net
  ServerAlias mysite.net

  ProxyRequests Off
  ProxyPreserveHost On

  <Proxy *>
    Order deny,allow
    Allow from all
  </Proxy>

  ProxyPass / http://localhost:8080/ retry=0
  ProxyPassReverse / http://localhost:8080/ retry=0
</VirtualHost>

[ssl 虚拟主机]

<VirtualHost *:443>
        ServerName www.mysite.net
        ServerAlias mysite.net

        ErrorLog /var/log/apache2/error.log

        LogLevel warn

        CustomLog /var/log/apache2/access.log combined
        ServerSignature On

        SSLEngine on
        SSLProxyEngine on
        SSLCertificateFile /etc/apache2/ssl/server.crt
        SSLCertificateKeyFile /etc/apache2/ssl/server.key

        ProxyRequests Off
        ProxyPreserveHost On
        ProxyPass / https://localhost:8443/ retry=0
        ProxyPassReverse / https://localhost:8443/ retry=0

</VirtualHost>

我的系统详细信息是：Apache/2.2.22 (Ubuntu) mod_jk/1.2.32 mod_ssl/2.2.22 OpenSSL/1.0.1 mod proxy_http 也已启用。

Answer 1

似乎在此站点上找到的停止然后启动 apache 和apachectl graceful重新启动（即实际上停止和启动而不是apachectl restart）之间存在差异：

This is a bit of a guess, and probably wrong, but does stopping and 
starting the server rather than restarting (they're different, 
restarting (including gracefully) doesn't kill the master process) 
help? As I understand it, there are issues in mod_proxy regarding the 
scoreboard size when changes to the config are made between restarts.