GDNSD-PLUGIN-SIMPLEFO(8) gdnsd GDNSD-PLUGIN-SIMPLEFO(8)NAMEgdnsd-plugin-simplefo - gdnsd plugin for simple primary->secondary
address failover
SYNOPSIS
Example gdnsd config fragment using this plugin:
plugins => {
simplefo => {
service_types => [ www ],
pubwww => {
primary => 192.0.2.1
secondary => 192.0.2.100
}
www6 => {
primary => 2001:DB8::1
secondary => 2001:DB8::100
}
mixed => {
service_types => [ www, xmpp ]
addrs_v4 => {
primary => 192.0.2.1
secondary => 192.0.2.100
}
addrs_v6 => {
service_types => up
primary => 2001:DB8::1
secondary => 2001:DB8::100
}
}
}
}
Example zonefile RRs:
www 180 DYNA simplefo!pubwww
www6 180 DYNA simplefo!www6
mix 180 DYNA simplefo!mixed
DESCRIPTIONgdnsd-plugin-simplefo is designed to do simple active/passive failover
between one primary address and one secondary address. The status of
the addresses are checked with standard gdnsd "service_types"
monitoring. If you need more than a simple two-address failover list,
the "metafo" plugin is more appropriate.
TOP-LEVEL PLUGIN CONFIG
At the top level of the plugin's configuration stanza, the special
parameter "service_types" is supported. These sets the default per-
resource "service_types" for all resources. The default default
"service_types" is "[ default ]", which does basic HTTP/1.0 polling for
200 OK status from "http://IPADDR:80/".
The rest of the hash entries at the top level are the names of the
resources you define. Each resource gets a configuration hash of its
own for containing resource-specific address info.
RESOURCE CONFIG
Within a resource, "service_types" is again supported, to set the
monitored service type(s) for this specific resource.
If "addrs_v4" is defined, it must be a hash containing two keys:
"primary" and "secondary", each of which has an IPv4 string address
value.
Similarly, if "addrs_v6" is defined, it must be a hash containing two
keys: "primary" and "secondary", each of which has an IPv6 string
address value.
If neither of those two sub-stanzas is defined, you must define a
single pair of "primary" and "secondary" addresses for the whole
resource. These can be of either address family, so long as they are
both the same family.
When "addrs_v4" and/or "addrs_v6" are used, "service_types" can also be
overridden within each, for different behavior per-address-family (e.g.
force one protocol always up/down).
OPERATIONAL MECHANICS
For each address family for which you have supplied data, the following
logic is applied independently:
· First, the worst monitored state of all "service_types" checks for
the primary address is obtained. If this state is "UP" or
"DANGER", the primary address is used.
· If the primary address was "DOWN", the secondary address is
checked: If the secondary is "UP" or "DANGER", it will be used. If
the secondary is also "DOWN", then the primary is used.
· In any case other than the primary being exactly "UP", the response
RR-set TTL from the zonefile will be cut in half for both address
families.
If both "primary" and "secondary" were "DOWN" for either address
family, this plugin will signal total resource failure to any upstream
module (geoip or metafo). The cutting of the TTL only happens once for
all address RRs, even if both families had a non-"UP" primary.
SEE ALSOgdnsd.config(5), gdnsd.zonefile(5), gdnsd(8), gdnsd-plugin-multifo(8)
The gdnsd manual.
COPYRIGHT AND LICENSE
Copyright (c) 2012 Brandon L Black <blblack@gmail.com>
This file is part of gdnsd.
gdnsd is free software: you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your
option) any later version.
gdnsd is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License along
with gdnsd. If not, see <http://www.gnu.org/licenses/>.
gdnsd 1.11.0 2013-12-06 GDNSD-PLUGIN-SIMPLEFO(8)
