Frequently-asked
Questions
This
FAQ serves as a supplement to the WhizzBee
Technical Overview and Administrator's
Guide. Please refer to these documents for general
information on WhizzBee and suggested solutions to common problems.
1.
Which WhizzBee product is most suitable for my site?
2.
Which RPM package(s) should I download? There are many listed
on the download page...
3. Can WhizzBee be also used for load-balancing
services other than HTTP?
4. I am using third-party modules for Apache,
can I use them with WhizzBee?
5. What do "dispatcher" and "management
console" mean?
6. I have installed the Cluster Server Package
in a new server node, but WhizzBee failed to detect it, why?
7. WhizzBee seemed to start successfully, but
it had no response when tested with a browser, why?
8. The management tool reported errors like "WITCH
failure", "Fail send load info", or "Web
server failure".
9. Does WhizzBee keep user session information?
It seems that some of the Web pages are generated incorrectly
in my site.
10.
I have encountered the "Web Server Failure" error,
why?
If
you cannot find a solution to your problem in this FAQ, you
may:
1.
Which WhizzBee product is most suitable for my site?
Please
refer to the WhizzBee
products page and deployment
scenarios.
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2.
Which RPM package(s) should I download? There are many listed
on the download page...
To
install WhizzBee, you will need two packages - Cluster
Server Package and Administration
Package. The Cluster Server Package is to be installed
in all cluster nodes (i.e. the dispatcher, backup dispatcher,
and all server nodes), while the Administration Package is
to be installed in the management console.
There
are four versions for each RPM package, namely RH72-UP, RH72-SMP,
RH71-UP, and RH71-SMP.
RH72-UP
- RedHat Linux 7.2 w/ uniprocessor kernel
RH72-SMP - RedHat Linux 7.2 w/ SMP kernel
RH71-UP - RedHat Linux 7.1 w/ uniprocessor kernel
RH71-SMP - RedHat Linux 7.1 w/ SMP kernel
If
you have a heterogeneous cluster that consists of RedHat 7.1
and 7.2 (UP or SMP) machines, you will need to download the
appropriate RPM package(s) for each of them. You may also
refer to the Case
Studies for typical deployment scenarios.
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3.
Can WhizzBee be also used for load-balancing services other
than HTTP?
Yes.
The dispatcher routes all IP traffic to the server nodes according
to their real-time CPU loads and the number of requests being
handled by individual servers. It does not differentiate among
the types of service being requested. However, it should be
noted that the required server software has to be enabled
and configured properly. Another note is that firewall rules
(ipchains/iptables) might be enforced at the dispatcher so
as to protect the server cluster from unauthorized access.
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4.
I am using third-party modules for Apache, can I use them with
WhizzBee?
WhizzBee
Family 2.0 is developed on top of the Apache
Web server v1.3.17 and inherently offers the dynamic shared
object (DSO) support. Users may edit the Apache configuration
file (/usr/local/whizzbee/conf/httpd.conf) in each of the
server nodes to specify configuration options for specific
modules.
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5.
What do "dispatcher" and "management console"
mean?
Please
refer to the cluster
architecture page for details.
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6.
I have installed the Cluster Server Package in a new server
node, but WhizzBee failed to detect it, why?
There
are several possibilities:
- WhizzBee
assumes all cluster nodes (not including the Management
Console) are inter-connected by using the eth0 network interface.
Any node not using the eth0 network interface for cluster
communication will not be detected.
- wbinit
should be run right after the installation of the cluster
server package. You may refer to the Administrator's
Guide for details on wbinit.
- Some
users reported that WhizzBee might not be able to detect
cluster nodes when the Management Console and cluster nodes
do not share the same IP subnet mask and default gateway.
Therefore, you are highly recommended to make sure all your
cluster nodes and the management console share the same
IP subnet mask and default gateway for first-time installation.
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7.
WhizzBee seemed to start successfully, but it had no response
when tested with a browser, why?
Please
make sure the Web requests sent to WhizzBee are not blocked
by firewall rules enforced in the dispatcher and/or server
nodes.
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8.
The management tool reported errors like "WITCH failure",
"Fail send load info", or "Web server failure".
Please
make sure you have downloaded and installed the correct version
of the cluster server package and the administration package.
For details, please refer to Q.2 above and the case
studies. Please also read Q.10 below for the "Web
server failure" error.
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9.
Does WhizzBee keep user session information? It seems that some
of the Web pages are generated incorrectly in my site.
WhizzBee
does keep user session information. However, it should be
stressed that the session information stored in a server node
might not be re-used by others. As a matter of fact, this
is a problem common to all cluster-based Web servers.
You
may enable the "Sticky session support" in order
to ensure the requests sent from a client are handled by the
same server node. If you would like to obtain a single view
on all user sessions being handled, you may develop your server-side
applications by using those cluster-aware packages (e.g. EJB,
etc.), or store all user session information in a backend
database system.
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10.
I have encountered the "Web Server Failure" error,
why?
- Each
server node must have a fully-qualified domain name (FQDN).
For example, if the hostname of a server node is "host1"
and it is within the domain "foo.com", its FQDN
would be "host1.foo.com".
- Make
sure the host file (/etc/hosts)
has a entry that specifies the IP address and the hostname
of the node itself. For instance:
192.168.1.1
host1 host1.foo.com
-
Note that a web server node cannot start the
bundled Apache server if there is a running web
server holding the configured listening port number.
Make sure that all other web server are stopped
before WhizzBee Web Server is configured and
run.
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