Как повысить отказоустойчивость dnscrypt за счёт избыточности?

CentOS 7

Создать каталог

mkdir /etc/dnscrypt

Файл /etc/systemd/system/dnscrypt.service

[Unit]
Description = DNSCrypt
Documentation = man:dnscrypt-proxy(8)
After = network.target iptables.target

[Service]
Type = forking
ExecStart = /etc/dnscrypt/dnscrypt.py start
Restart = always
ExecStopPost = /etc/dnscrypt/dnscrypt.py stop

Перечитываем конфигурацию systemd

systemctl daemon-reload

Файл /etc/dnscrypt/dnscrypt.py

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-

__author__ = 'RemiZOffAlex'
__copyright__ = '(c) RemiZOffAlex'
__license__ = 'MIT'
__email__ = 'remizoffalex@mail.ru'
__url__ = 'http://remizoffalex.ru'

# Т.к. на основном интерфейсе 127.0.0.1 висит bind,
# то нумерация начинается с 2

import os
import sys
import json
from subprocess import Popen, PIPE

CONFFILE = '/etc/dnscrypt/dnscrypt.conf'
LOGFILE = '/var/log/dnscrypt.log'

#Run shell command
def run_cmd(cmd):
   p = Popen(cmd, shell=True, stdout=PIPE)
   output = p.communicate()[0]
   return output

def start():
   with open(CONFFILE, 'r') as f:
       confdata = json.load(f)
    
   for idx,item in enumerate(confdata):
       if  os.path.exists(item['pid'])==True:
           print('Service <{}> already running'.format(item['description']))
       else:
           print('Starting service…')
           run_cmd('/usr/sbin/ip addr add {}/32 dev lo label lo:{}'.format(item['ip'], idx))
           run_cmd('/bin/touch ' + item['pid'])
           run_cmd('/bin/chmod 666 ' + item['pid'])
           run_cmd('/usr/sbin/dnscrypt-proxy --daemonize --logfile=' + item['log'] + ' ' +
               '--pidfile=' + item['pid'] + ' --local-address=' + item['ip'] + ':53' + ' ' +
               '--provider-key=' + item['key'] + ' ' +
               '--provider-name=' + item['name'] + ' --resolver-address=' + item['address'])
           print('Service started')

def stop():
   with open(CONFFILE, 'r') as f:
       confdata = json.load(f)
    
   for idx,item in enumerate(confdata):
       if  os.path.exists(item['pid'])==False:
           print('Service <{}> not running'.format(item['description']))
       else:
           print('Stopping service…')
           run_cmd('kill -s 15 $(cat "{}")'.format(item['pid']))
           run_cmd('rm -f "{}"'.format(item['pid']))
           print('Service stopped')
       run_cmd('/usr/sbin/ip addr del {}/32 dev lo label lo:{}'.format(item['ip'], idx))

def restart():
   stop()
   start()


if __name__ == "__main__":
   if len(sys.argv) == 2:
       if 'start' == sys.argv[1]:
           start()
       elif 'stop' == sys.argv[1]:
           stop()
       elif 'restart' == sys.argv[1]:
           restart()
       else:
           print("Unknown command")
           sys.exit(2)
       sys.exit(0)
   else:
       print("Usage: %s start|stop|restart" % sys.argv[0])
       sys.exit(2)

Делаем исполнимым

chmod +x /etc/dnscrypt/dnscrypt.py

Файл /etc/dnscrypt/dnscrypt.conf

[
   {
       "log": "/var/log/dnscrypt/dnscrypt2.log",
       "ip": "127.0.0.2",
       "description": "DNSCrypt.eu Holland",
       "pid": "/var/run/dnscrypt2.pid",
       "address": "176.56.237.171:443",
       "key": "67C0:0F2C:21C5:5481:45DD:7CB4:6A27:1AF2:EB96:9931:40A3:09B6:2B8D:1653:1185:9C66",
       "name": "2.dnscrypt-cert.resolver1.dnscrypt.eu"
   },
   {
       "log": "/var/log/dnscrypt/dnscrypt3.log",
       "ip": "127.0.0.3",
       "description": "Cypherpunks.ru",
       "pid": "/var/run/dnscrypt3.pid",
       "address": "77.51.181.209:5353",
       "key": "1838:CCA3:D953:0A66:3433:5D50:05BD:3758:44E3:977E:E868:2B6C:5528:12BD:A78D:2E99",
       "name": "2.dnscrypt-cert.cypherpunks.ru"
   },
   {
       "log": "/var/log/dnscrypt/dnscrypt4.log",
       "ip": "127.0.0.4",
       "description": "Babylon Network Netherlands 0",
       "pid": "/var/run/dnscrypt4.pid",
       "address": "87.253.152.190:5353",
       "key": "8794:070A:143D:35CA:1CA6:32E7:B189:3028:4EAE:5DAF:EBB4:01E3:DF52:E9F0:37AB:D182",
       "name": "2.dnscrypt-cert.babylon.network"
   },
   {
       "log": "/var/log/dnscrypt/dnscrypt5.log",
       "ip": "127.0.0.5",
       "description": "CS England DNSCrypt server",
       "pid": "/var/run/dnscrypt5.pid",
       "address": "5.101.137.251:443",
       "key": "3133:72AD:5956:32C2:416B:872F:098F:851B:DDB9:6528:4C6C:BE9A:4F19:0964:30DB:A95A",
       "name": "2.dnscrypt-cert.cryptostorm.is"
   }
]

Запускаем

systemctl start dnscrypt