The point of this is to integrate with ExaBGP and etcd. Basically this script will monitor keys in etcd, and announce/withdraw things via the ExaBGP api. Right now it's a proof of concept, but I plan on finishing it.
Usage of ./bgpcommander:
-c=http://127.0.0.1:4001: Comma separated list of etcd cluster members
-n="killallhumans.local": Override node's name
-p="/tmp": Path to store healthcheck scripts
When running in conjuction with ExaBGP, a process configuration like this is inserted:
process bgpcommander {
encoder json;
neighbor-changes;
run /path/to/bgpcommander;
}
Any of the flags available can be passed to override various defaults. You probably want to point to a real etcd cluster for example. Once you have this configured and the process is running, there are a few keys in etcd that you'll want to modify.
Creating a new route
All routes exist in the /bgp/routes directory and can be created with a couple curl commands.
# This key is what is used to announce or withdraw routes with ExaBGP
$ curl localhost:4001/v2/keys/bgp/routes/CUSTOM_ROUTE/config -XPUT \
--data-urlencode value="route 172.16.1.5/32 next-hop self med 100"
# This key is what is downloaded and ran as a healthcheck for the route.
# As long as the script returns 0, the healthcheck is considered passing. If anything
# else is returned, a withdraw command is used to remove the route.
$ cat << EOF > mytest.sh
#!/bin/sh
dig @172.16.1.5 google.com
EOF
$ curl localhost:4001/v2/keys/bgp/routes/CUSTOM_ROUTE/healthcheck -XPUT \
--data-urlencode [email protected]
Assigning a route to a node
Unless you specify that a node should advertise a route, it will not. To do that you simply add to the subscribedRoutes key in etcd for that node.
# This key should be a space separate list of route names that you would like to
# have this node monitor and announce
$ curl localhost:4001/v2/keys/bgp/node/killallhumans.local/subscribedRoutes -XPUT -d value="CUSTOM_ROUTE"
Checking for neighbor state
In addition to controlling routes, it's easy to grab state information about neighbors. This data is available like so:
$ curl localhost:4001/v2/keys/bgp/node/killallhumans.local/neighbors?recursive=true
# TODO: add sample output here, basically you have state and ip address information per neighbor