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Ultra Monkey L7 [offsite]
Linux Virtual Server |
All topologies include sample configuration files for both a single virtual
service, and a contiguous network of virtual services. Given an
understanding of how to correctly configure interfaces and routes on the
nodes, these topologies should help map out a topology for your network.
- High Availability
- Load Balancing
- High Availability and Load Balancing
- High Capacity Highly Availability and Load Balancing
- Streamline Highly Availability and Load Balancing
Using Firewall Marks
Firewall marks provide a powerful mechanism to group services together.
They make use of the powerful
netfilter patcker filtering
framework to match traffic bound for a virtual service and
mark these packets internally with a firewall mark.
This firewall mark is used by LVS to identify packets that
should be load balanced and forwarded to real servers..
This mechanism can be used with any of the Load Balanced
topologies described. An example of using
firewall marks with high availability
and load balancing is provided.
Load Balancing Statistics
LVS provides statistics that are useful
for examining the performance and troubleshooting problems.
Ultra Monkey provides Load Balancing
and High Availability. Often this goes in hand in
hand with sharing or replicating data between machines.
A list of cluster Filesystem technologies and lan mirroring
techniques is maintained on
Rsync is also a useful
tool for replicating data between real servers.
Using Private Addresses
RFC 1918 private addresses
may be used for the real servers to minimise publicly routable IP address
allocation requirements. If using NAT as the
forwarding mechanism this is trivial as the hosts will be masqueraded by
the Linux Virtual Server host. If direct routing is used then
RFC 1918 addresses may still be used for the real servers as the
source address will be set to that of the virtual service. This does
however result in the real servers being unable to initiate connections
outside networks on which the RFC 1918 addresses are routed.
When debugging these topologies it may be useful to examine the flow of
traffic on the ethernet networks. A useful tools for doing this
The following example uses tcpdump to show all ARP, ICMP and port 80
traffic on the interface eth0.
tcpdump -n -i eth0 port 80 or ICMP or ARP
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