# **Guide to use horcrux with Namada Blockchain for High Availability and Security** # **Design:** 3 horcrux servers as remote Signers cluster 3 Namada Nodes. ( Best to host with different Hosting Providers Ex: AWS , Google , Contabo ) **Software Requirements:** OS : Ubuntu 22.04.3 App : horcrux v3.2.3 **Hardware Requirements for Signers:** 3x VPS w/ 2 CPU, 2 GB RAM, 20 GB SSD * FW open ports : 19901 for Nodes and 2222 for Signers - you can chose any port you want * DNS records : 3 cname ( node1 , node2,node3 ) for nodes and 3 cname ( signer1,signer2,signer3 ) for signers This guide will assume you already using single Namada node and it is working as validator and need to use horcrux as remote signing cluster with 3 Namada nodes to provide High Availability and Security by eliminating the single point of Failure and to remove the validator signing key from the node for more security . **run These steps on your all signers servers** * Create directory to organize your horcrux files ``` mkdir horcruxNamada ``` ``` cd horcruxNamada ``` * Download horcrux binary v3.2.3 to all your signers ``` wget https://github.com/strangelove-ventures/horcrux/releases/download/v3.2.3/horcrux_linux-amd64 ``` * rename horcrux_linux-amd64 to horcrux and copy it to /usr/bin/ and /usr/local/sbin/ ``` mv horcrux_linux-amd64 horcrux sudo cp horcrux /usr/bin/ sudo cp horcrux /usr/local/sbin/horcrux ``` * Create a horcrux service ``` sudo nano /etc/systemd/system/hornamada.service ``` * paste below content inside ``` [Unit] Description= horcrux Signer For Namada After=network.target [Service] Type=simple User=YOUR_USER_NAME WorkingDirectory=PATH_To_horcruxNamada ExecStart=/usr/bin/horcrux start --home PATH_To_horcruxNamada Restart=on-failure RestartSec=3 LimitNOFILE=4096 [Install] WantedBy=multi-user.target ``` * Enable the service using ``` sudo systemctl enable hornamada.service ``` **These steps are only for your first Signer ( Signer 1 )** * copy your Namada priv_validator_key.json from namada directory cometbft/config to horcruxNamada folder located in your first horcrux signing server Signer 1 ** * we will use FQDN instead of IP for easy preferred way please note that we will use port 19901 for Nodes and port 2222 for signers please be sure these ports are open in your FW accordingly also , Please be sure about your dns cnames for nodes and signers * `horcrux config init --node "tcp://node1.YOURDOMAIN:19901" --node "tcp://node2.YOURDOMAIN:19901" --node "tcp://node3.YOURDOMAIN:19901" --cosigner "tcp://signer1.YOURDOMAIN.net:2222" --cosigner "tcp://signer2.YOURDOMAIN:2222" --cosigner "tcp://signer3.YOURDOMAIN:2222" --threshold 2 --grpc-timeout 1500ms --raft-timeout 1500ms --home PATH_To_horcruxNamada` * `horcrux create-ecies-shards --shards 3 --home PATH_To_horcruxNamada` * `horcrux create-ed25519-shards --chain-id NAMADA_CHAIN_ID --key-file PATH_To_horcruxNamada/priv_validator_key.json --threshold 2 --shards 3 --home PATH_To_horcruxNamada ` * the above steps will generate cosigner communication encryption keys and you should find new files and new folders inside your horcruxNamada that similar to below ``` priv_validator_key.json config.yaml cosigner_1/ecies_keys.json cosigner_2/ecies_keys.json cosigner_3/ecies_keys.json state ``` * Now move your priv_validator_key.json to secure location as we don’t need it anymore * create a new file inside state folder named NAMADA-CHAIN-ID_priv_validator_state.json , This file will hold the signing state for the cluster , please change the NAMADA-CHAIN-ID with the Namada Chain ID * paste the blew content to it ``` { "height": "0", "round": "0", "step": 3 } ``` * copy horcruxNamada folder to your both other signers using scp * After copying your horcruxNamada folder to the second signer you will need to delete both folders named ( cosigner_1 , cosigner_3 ) and their content from horcruxNamada folder inside ( signer 2 ) , This will lead to having Only two Folders cosigner_2 folder and state folder * Copy cosigner_2 content ( ecies_keys.json ) to horcruxNamada Folder So in the end in singer 2 horcruxNamada folder should be link this ``` config.yaml ecies_keys.json cosigner_2 state\NAMADA-CHAIN-ID_priv_validator_state.json ``` * repeat same steps with signer 3 . horcruxNamada folder in signer 3 server should be link this ``` config.yaml ecies_keys.json cosigner_3 state\NAMADA-CHAIN-ID_priv_validator_state.json ``` **These steps will be applied for First Namada Node** * configure namada to start using the horcrux cluster for signing blocks by editing config.toml located in Namada config folder * Search for ``` priv_validator_laddr = "" ``` then change it to ``` priv_validator_laddr = "" ``` * now remove the priv_validator_key.json from the node and store it in secure location as we don’t need it anymore * stop NAMADA node and ONLY after it stopped open the file priv_validator_state.json inside the cometbft/data and check the "height" number * go to each signer and edit the NAMADA-CHAIN-ID_priv_validator_state.json inside the horcruxNamada/state with the "height" number you just got from your Namada Validator state should be like this ``` { "height": "YOUR_NAMADA_height", "round": "0", "step": 3 } ``` * Start your first horcrux signer process inside signer one and check the logs ``` sudo systemctl restart hornamada.service && sudo journalctl -u hornamada.service -f --output cat ``` * start signer 2 and signer 3 horcrux signer process and watch the logs * Now start your Namada process on your First Node and check the logs * If everything is working your node should start signing blocks * please install 2 Namada Nodes in different servers and edit their config file as we did with node 1 **WARNING :** **FOR ALL RUNNING NODES IN THE CLUSTER BE SURE YOU ARE USING priv_validator_laddr = "" AND REMOVE THE ORIGNAL priv_validator_key.json FROM ALL NODES PLEASE NOTE THAT USING REMOTE SIGNING COULD LEAD TO DOUBLE SIGNING AND SLASHING IF YOUR NODE SIGNED SAME BLOCK TWICE, SO BE SURE THAT NEVER USE LOCAL AND REMOTE SIGNING SAME TIME .** **TROUBLESHOUTING :** * check FW ports * check dns for signers and node cnames * check files and folder paths for horcrux * check same horcrux version on all signers * PING RTT time between nodes and signers ( more delay more issues )