BGP Configuration
This document describes the commands available in calicoctl for managing BGP. It covers configuration of:
- Global default node AS Number
- The full node-to-node mesh
- Global BGP Peers
- Node-specific BGP Peers
The global default node AS Number is the AS Number used by the BGP agent on a Calico node when it has not been explicitly specified. Setting this value simplifies configuration when your network topology allows all of your Calico nodes to use the same AS Number.
The full node-to-node mesh option provides a mechanism to automatically configure peering between all Calico nodes. When enabled, each Calico node automatically sets up a BGP peering with every other Calico node in the network. By default this is enabled. However, the full node-to-node mesh is only useful for small scale deployments and where all Calico nodes are on the same L2 network. We generally expect the full node-to-node mesh to be disabled and explicit BGP peering configured.
Explicit BGP peers may be configured globally or for a particular node.
A global BGP peer is a BGP agent that peers with every Calico node in the network. A typical use case for a global peer might be a mid-scale deployment where all of the Calico nodes are on the same L2 network and are each peering with the same Route Reflector (or set of Route Reflectors).
At scale, different network topologies come in to play. For example, in the AS per Rack model discussed in the reference material, each Calico node peers with a Route Reflector in the Top of Rack (ToR) switch. In this case the BGP peerings are configured on a per-node basis (i.e. these are node-specific peers). In the AS Per Rack model, each Calico node in a rack will be configured with a node-specific peering to the ToR Route Reflector.
Configuring the default node AS number
When creating a Calico node, you can optionally specify an AS number to use for the node. If no AS number if specified, the node will use the global default value.
Use the calicoctl bgp default-node-as command to set the global default AS
number. If no value is configured, the default AS number is 64511.
If all of your Calico nodes are within the same AS, but you require a different AS number to be used (e.g because you are peering with a border router), changing the default AS number to the value you require eliminates the need to explicitly set it on a per Calico node basis. For more complicated topologies where you are explicitly setting the AS number on each node, the default value will not be used and therefore using this command is not necessary.
Example
To set the default AS number to 64512, run the following calicoctl command on any node:
$ calicoctl bgp default-node-as 64512
To view the current default value, run the command without specifying an AS number, the command will output the current value.
$ calicoctl bgp default-node-as
64512
Disabling the full node-to-node BGP mesh
If you are explicitly configuring the BGP topology for your Calico network,
you may wish to disable the full node-to-node mesh. Use the
calicoctl bgp node-mesh command to disable or re-enable the mesh.
If you are building your network from scratch and do not need the full node-to-node mesh we recommend turning off the mesh before configuring your nodes. If you are updating your network from a full-mesh topology to a different topology (e.g. to start using a cluster of route reflectors to increase scaling), configure the appropriate peers before disabling the mesh to ensure continuity of service.
Example
To turn off the full BGP node-to-node mesh run the following command on any node:
$ calicoctl bgp node-mesh off
If you need to turn the full BGP node-to-node mesh back on run the following command on any node:
$ calicoctl bgp node-mesh on
To view whether the BGP node-to-node mesh is on or off, enter the command without specifying the parameter, the command will output the current state.
$ calicoctl bgp node-mesh
on
Configuring a global BGP peer
If your network topology includes BGP speakers that will be peered with every
Calico node in your deployment, you can use the calicoctl bgp peer commands
to set up the peering on your Calico nodes. We refer to these as global peers
because they peer with every Calico node.
Two situations where global BGP peer configuration is useful are when adding a border router that is peering into a full node-to-node mesh, or configuring a Calico network that uses one or two route reflectors to provide moderate scale-out capabilities. In the latter case, each Calico node would peer to each of the Route Reflectors and the full node-to-node mesh would be disabled.
Example
To add a global BGP peer at IP address 192.20.30.40 with AS number 64567 run the following command on any node:
$ calicoctl bgp peer add 192.20.30.40 as 64567
To remove a global BGP peer that was configured with IP address 192.20.30.40 (the AS number is not required when deleting) run the following command on any node:
$ calicoctl bgp peer remove 192.20.30.40
To view the current list of global peers run the following command on any node:
$ calicoctl bgp peer show
+----------------------+--------+
| Global IPv4 BGP Peer | AS Num |
+----------------------+--------+
| 192.20.30.40 | 64567 |
+----------------------+--------+
+----------------------+--------+
| Global IPv6 BGP Peer | AS Num |
+----------------------+--------+
| aa:bb::ff | 64514 |
+----------------------+--------+
Configuring a node specific BGP peer
If your network topology requires specific peerings for each Calico node, you
can use the calicoctl node bgp peer commands to set up the peers specific to
a Calico nodes. We refer to these as node specific peers.
Configuring node specific peers is necessary when the BGP topology is more complicated and requires different peerings on different nodes. For example, the AS per Rack model or AS per Compute Server model described in the reference material.
Example
To add a BGP peer at IP address aa:bb::ff with AS number 64514, peering with Calico node “Node1”, run the following command from the “Node1” command line:
Node1$ calicoctl node bgp peer add aa:bb::ff as 64514
To remove a BGP peer that was configured with IP address aa:bb::ff (the AS number is not required), peering with Calico node “Node1”, run the following command from the “Node1” command line:
Node1$ calicoctl bgp peer remove aa:bb::ff
To view the current list of node specific peers that are configured to peer with Calico node “Node1”, run the following command from the “Node1” command line:
Node1$ calicoctl node bgp peer show
No IPv4 BGP Peers defined for this node.
+-----------------------------+--------+
| Node specific IPv6 BGP Peer | AS Num |
+-----------------------------+--------+
| aa:bb::ff | 64514 |
+-----------------------------+--------+
Checking the status of the BGP peers
To display the status of all BGP peerings for a specific node, use the
calicoctl status command. This displays the status of all BGP peers for
that node - this includes the peers that are automatically configured as part
of the full node-to-node mesh and the explicitly configured global peers and
node specific peers.
Understanding the status of the BGP peerings is a useful first step in diagnosing why routes may not be advertised across your network resulting in incorrect connectivity between your workloads.
Example
To check the status of the peerings on Calico node “Node1”, run the following command from the “Node1” command line:
Node1$ calicoctl status
calico-node container is running. Status: Up 13 minutes
IPv4 BGP status
+--------------+-------------------+-------+----------+-------------+
| Peer address | Peer type | State | Since | Info |
+--------------+-------------------+-------+----------+-------------+
| 172.17.42.21 | node-to-node mesh | up | 16:17:25 | Established |
| 10.20.30.40 | global | start | 16:28:38 | Connect |
| 192.10.0.0 | node specific | start | 16:28:57 | Connect |
+--------------+-------------------+-------+----------+-------------+
IPv6 BGP status
+--------------+-------------------+-------+----------+-------------+
| Peer address | Peer type | State | Since | Info |
+--------------+-------------------+-------+----------+-------------+
| aa:bb::ff | node-to-node mesh | up | 16:17:26 | Established |
+--------------+-------------------+-------+----------+-------------+