Simple example using etcdv3 as DB for tf states + locks (paxos comes in play ;))

tf_remote_state_etcd.sh

#!/bin/bash
set -ex

# brew install etcd
etcd &

# check etcd
ETCDCTL_API=3 etcdctl put foo bar
ETCDCTL_API=3 etcdctl get foo

# prepare tf main

cat <<EOF > main.tf
terraform {
  backend "etcdv3" {
    endpoints = ["0.0.0.0:2379"]
    lock      = true
    prefix    = "terraform-state/"
  }
}

data "terraform_remote_state" "tf_remote_etcd" {
  backend = "etcdv3"
  config = {
    endpoints = ["0.0.0.0:2379"]
    lock      = true
    prefix    = "terraform-state/"
  }
}

resource "local_file" "my_file" {
  filename = "test-file.txt"
  content  = "Hey, its a test file"
}
EOF

# brew install terraform
terraform init
terraform fmt
terraform validate
terraform plan
terraform apply

# check remote state
ETCDCTL_API=3 etcdctl get --prefix "terraform-state/"

# do not forget to shut down etcd, ps aux | grep etcd ->> kill -9 PID