TMKMS

The Tendermint Key Management System (or TMKMS) should be used by any validator currently or intending to be in the active validator set. This application mitigates the risk of double-signing and provides high-availability to validator keys while keeping these keys on a separate physical host. While TMKMS can be used on the same machine as the validator, it is recommended to be on a separate host.

Prepare TMKMS Dependencies

Start by opening the node you intend to run TMKMS (not the node you validate on) and install the following dependencies:

Rust

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
source $HOME/.cargo/env

GCC

sudo apt update
sudo apt install git build-essential ufw curl jq snapd --yes

Libusb

apt install libusb-1.0-0-dev

If on x86_64 architecture:

export RUSTFLAGS=-Ctarget-feature=+aes,+ssse3

Setup TMKMS

In this example, we will be compiling from the github source code using the --features=softsign flag, however you may use --features=yubihsm if you want to use a yubikey (ledger support is not working properly at the moment, and this guide will not go into using yubihsm).

Now we will transfer your validator private key from your validator to your VM running TMKMS. You can do this manually or though scp. I will use scp in this example (the validator has the IP of 123.456.32.123):

Then, import the private validator key into tmkms:

Please note at this point, you could delete the priv_validator_key.json from both your validator node and tmkms node and store it safely offline in case of an emergency. This newly created priv_validator_key will be what TMKMS will use to sign for your validator.

Now, modify the tmkms.toml file

In this example, my validator has the IP address of 123.456.32.123 and we will be using port 26659 to feed the validator key to the validator. We will also be using chain_id sge-internal-tesnet-1.3:

Now, modify your validators config.toml to use the port you selected in the tmkms.toml file:

It is also recommended to comment out the priv_validator_key_file line and the priv_validator_state_file line:

Next, stop the validator. Move back to your VM running TMKMS and start it:

You will see error logs like the following:

Now, start your osmosis validator on the validator node:

Your TMKMS node will now show logs like the following:

You should now be signing blocks! If you cancel the TMKMS process, you will no longer sign blocks and will stop syncing. If you restart the TMKMS process, your validator node will continue to sync from where it left off.

Final Notes

Please note that this is a bare minimum setup. More robust settings such as setting up a firewall to only allow your TMKMS node to get through the priv_validator_laddr port would make your validator even more secure.

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