Article ID: 117511, created on Sep 26, 2013, last review on Aug 12, 2014

  • Applies to:
  • Operations Automation 5.5

Symptoms

Clicking the 'Validate Configuration' button on the 'General' tab in the Web Cluster properties in the POA Provider Control Panel produces the warning like this:

Web Server #ID configuration is not in sync with Director: file(s) /etc/httpd/conf/httpd.conf have different content

See the screenshot below:

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Cause

POA compares MD5 sum of the /etc/httpd/conf/httpd.conf file on all web servers in the cluster and shows warning if checksum is not the same across all the servers.

The web servers have different httpd.conf files because they include the 'HEADER' directive with the ID of the particular web server (whihc is unique for every single webserver, of course). See the example below:

[root@ngweb1 ~]# grep X-SERVER /etc/httpd/conf/httpd.conf
HEADER always set X-SERVER "74"

[root@ngweb2 ~]# grep X-SERVER /etc/httpd/conf/httpd.conf
HEADER always set X-SERVER "75"

As it can be seen above the httpd.conf file on the ngweb1 web server contains the HEADER directive with the 'HEADER always set X-SERVER "74"' value, while the httpd.conf file on the ngweb2 web server contains the HEADER directive with the 'HEADER always set X-SERVER "75"' value. Thus, MD5 sums of the httpd.conf files on two servers are different.

Resolution

The problem is going to be resolved in the POA 5.5.2 in scope of the request POA-80981.

In the mean time use the following resolution: remove the HEADER directive from the httpd.conf file on all web servers in the NG cluster and add in into an included file instead, e.g. into the /etc/httpd/conf.d/ng_custom.conf (this file is included from the /etc/httpd/conf/httpd.conf file).

So, on the 'ngweb1' server the /etc/httpd/conf.d/ng_custom.conf file should contain the following value:

HEADER always set X-SERVER "74"

And on the 'ngweb2' server the /etc/httpd/conf.d/ng_custom.conf file should contain the following value:

HEADER always set X-SERVER "75"

The /etc/httpd/conf/httpd.conf file on all web servers in cluster should not contain the HEADER directive at all.

After the modifications above were done calculate MD5 sum of the /etc/httpd/conf/httpd.conf file on all web servers, it must be the same.

Restart the Apache server on web servers to apply the changes:

# /etc/init.d/httpd restart

After the steps above were applied the warning should disappear in the POA Provider Control Panel after clicking the 'Validate Configuration' button.

Search Words

NG cluster

Web Server configuration is not in sync with Director

Validate Configuration

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