local-network-setup.md

Local Network Setup For Testing Validator Set pallet

If you are using the Substrate node template and want to set up a local network to test/use the validator set pallet, follow the steps below. Make sure you have completed all the steps in the readme.md before doing this.

Local Network

Once your node template compiles after adding the validator set pallet, the first thing we need to do is run at least 3 nodes as a local network. The node template comes with two predefined chain configurations - dev and local. We will be using the local config that already has two values in the initial_authorities genesis config. These are accounts generated using the dev seed for Alice and Bob.

Step 1

Run the Alice validator:

./target/release/node-template --chain=local --alice --base-path ~/tmp/a --port=30334 --ws-port 9944 --ws-external --rpc-cors=all --rpc-methods=Unsafe --rpc-external

Note that we have provided --chain=local, and custom values for base-path, port, ws-port. These custom value are used to avoid conflicts when running all nodes on local machine. If you are running nodes on separate servers, you can leave these as defaults.

The remaining parameters --ws-external --rpc-cors=all --rpc-methods=Unsafe --rpc-external are used to connect ws and rpc from a remote machine, and to allow rpc calls. For production setup, this should be double-checked, and only allowed if required. Do not use these as-is for production nodes.

Step 2

Next, once the Alice node starts, copy it's node address from the console logs:

Local node identity is: 12D3KooWQXBxhGvmbcb8siLZWf7bNzv3KrzEXhi9t2VbDGP57zR9

In this case, 12D3KooWQXBxhGvmbcb8siLZWf7bNzv3KrzEXhi9t2VbDGP57zR9 is the node identity. We will need this as the bootnode address for other nodes.

Step 3

Next, run the Bob and Charlie nodes:

./target/release/node-template --chain=local --bob --base-path ~/tmp/b --port=30335 --ws-port 9945 --ws-external --rpc-cors=all --rpc-methods=Unsafe --rpc-external --bootnodes /ip4/127.0.0.1/tcp/30334/p2p/12D3KooWQXBxhGvmbcb8siLZWf7bNzv3KrzEXhi9t2VbDGP57zR9

and,

./target/release/node-template --chain=local --charlie --base-path ~/tmp/c --port=30336 --ws-port 9946 --ws-external --rpc-cors=all --rpc-methods=Unsafe --rpc-external --bootnodes /ip4/127.0.0.1/tcp/30334/p2p/12D3KooWQXBxhGvmbcb8siLZWf7bNzv3KrzEXhi9t2VbDGP57zR9

As you can see, we have added an additional parameter when running Bob and Charlie nodes to provide a bootnode. The bootnodes parameter has the Alice node's identity. You should replace it with what you get in Step 2 above.

Step 4

Open Polkadot JS Apps in your browser and connect it to the Charlie node using its ws endpoint. In this case, it would be: ws://127.0.0.1:9946. Remember we used a custom ws-port. In the Network Explorer you should see that Alice and Bob are producing blocks, while Charlie is not. This is because Charlie is not part of initial authorities from genesis config.

Step 5

From Charlie node connected Polkadot JS Apps instance, make an RPC call author - rotate_keys. This will print public session keys for Charlie node.

Step 6

Now make an extrinsic call from Charlie account - Session - set_keys. We need to use the substrings of the string obtained in Step 5, in the keys: NodeTemplateRuntimeOpaqueSessionKeys input fields. First remove the 0x from the beginning. Then divide that string into equal parts of 32 bytes each. Prefix 0x to each of these smaller strings, and then enter them in the input fields for each of the keys (aura, grandpa, imonline). Put 0x in the proof input.

Step 7

Finally, add Charlie as a validator by calling the add_validator extrinsic of the Validator Set pallet using sudo. Alice should be caller of this extrinsic, because Alice is set as the sudo key in node template.

Step 8

Go to the Network Explorer page in Polkadot JS Apps and note the session number. After two sessions from this, the Charlie node should start authoring blocks and you should be able to see under the recent blocks list on the same page.

Following these steps, you can add more validators.