Bootnodes
Configuring bootnodoes
You can use bootnodes to initially discover peers. Bootnodes are regular nodes used to discover other nodes.
In private networks for development or testing purposes, specify at least one bootnode.
In production networks, configure two or more nodes as bootnodes.
!!! note "Mainnet and public testnets"
Specify a bootnode
To start a node, specify a bootnode enode for P2P discovery, using the --bootnodes
option.
!!! example
The default host and port advertised to other peers for P2P discovery is 127.0.0.1:30303
. To specify a different host or port, use the --p2p-host
and --p2p-port
options.
By default, peer discovery listens on all available network interfaces. If the device Besu is running on must bind to a specific network interface, specify the interface using the --p2p-interface
option.
Configure bootnodes in a production network
A network must have at least one operating bootnode. To allow for continuity in the event of failure, configure two or more bootnodes in a production network.
We don't recommend putting bootnodes behind a load balancer because the enode relates to the node public key, IP address, and discovery ports. Any changes to a bootnode enode prevents other nodes from being able to establish a connection with the bootnode. This is why we recommend putting more bootnodes on the network itself.
To ensure a bootnode enode doesn't change when recovering from a complete bootnode failure:
Create the node key pair (that is, the private and public key) before starting the bootnode.
When creating bootnodes in the cloud (for example, AWS and Azure), attempt to assign a static IP address to them. If your network is:
Publicly accessible, assign an elastic IP.
Internal only, specify a private IP address when you create the instance and record this IP address.
We recommend storing the bootnode configuration under source control.
To allow for failure, specify all bootnodes on the command line (even to the bootnodes themselves).
Add and remove bootnodes
Adding new bootnodes is a similar process to creating bootnodes. After creating the bootnodes and adding them to the network, update the --bootnodes
command line option for each node to include the new bootnodes.
When adding bootnodes, you don't need to restart running nodes. By updating the --bootnodes
option, the next time you restart the nodes, the nodes connect to the new bootnodes.
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