extensions/libxt_cluster.man

Allows you to deploy gateway and back-end load-sharing clusters without the
need of load-balancers.
.PP
This match requires that all the nodes see the same packets. Thus, the cluster
match decides if this node has to handle a packet given the following options:
.TP
\fB\-\-cluster\-total\-nodes\fP \fInum\fP
Set number of total nodes in cluster.
.TP
[\fB!\fP] \fB\-\-cluster\-local\-node\fP \fInum\fP
Set the local node number ID.
.TP
[\fB!\fP] \fB\-\-cluster\-local\-nodemask\fP \fImask\fP
Set the local node number ID mask. You can use this option instead
of \fB\-\-cluster\-local\-node\fP.
.TP
\fB\-\-cluster\-hash\-seed\fP \fIvalue\fP
Set seed value of the Jenkins hash.
.PP
Example:
.IP
iptables \-A PREROUTING \-t mangle \-i eth1 \-m cluster
\-\-cluster\-total\-nodes 2 \-\-cluster\-local\-node 1
\-\-cluster\-hash\-seed 0xdeadbeef
\-j MARK \-\-set-mark 0xffff
.IP
iptables \-A PREROUTING \-t mangle \-i eth2 \-m cluster
\-\-cluster\-total\-nodes 2 \-\-cluster\-local\-node 1
\-\-cluster\-hash\-seed 0xdeadbeef
\-j MARK -\-set\-mark 0xffff
.IP
iptables \-A PREROUTING \-t mangle \-i eth1
\-m mark ! \-\-mark 0xffff \-j DROP
.IP
iptables \-A PREROUTING \-t mangle \-i eth2
\-m mark ! \-\-mark 0xffff \-j DROP
.PP
And the following commands to make all nodes see the same packets:
.IP
ip maddr add 01:00:5e:00:01:01 dev eth1
.IP
ip maddr add 01:00:5e:00:01:02 dev eth2
.IP
arptables \-A OUTPUT \-o eth1 \-\-h\-length 6
\-j mangle \-\-mangle-mac-s 01:00:5e:00:01:01
.IP
arptables \-A INPUT \-i eth1 \-\-h-length 6
\-\-destination-mac 01:00:5e:00:01:01
\-j mangle \-\-mangle\-mac\-d 00:zz:yy:xx:5a:27
.IP
arptables \-A OUTPUT \-o eth2 \-\-h\-length 6
\-j mangle \-\-mangle\-mac\-s 01:00:5e:00:01:02
.IP
arptables \-A INPUT \-i eth2 \-\-h\-length 6
\-\-destination\-mac 01:00:5e:00:01:02
\-j mangle \-\-mangle\-mac\-d 00:zz:yy:xx:5a:27
.PP
In the case of TCP connections, pickup facility has to be disabled
to avoid marking TCP ACK packets coming in the reply direction as
valid.
.IP
echo 0 > /proc/sys/net/netfilter/nf_conntrack_tcp_loose