I added a monthly crontab now: @monthly bash cronMonthly.sh &

cronMonthly.sh
Code:
cd KILLTUBE
node update_ssl.js
update_ssl.js
Code:
const { execSync } = require('child_process');
const { readFileSync, writeFileSync } = require('fs');
const file_get_contents = filename => readFileSync(filename, 'utf8');
const email = 'lama12345@gmail.com';
const domains = [
	'killtube.org',
	'www.killtube.org',
	//'tracker.killtube.org',
].map(domain => '-d ' + domain).join(' ');
function system(cmd) {
  const stdout = execSync(cmd).toString().trim();
	console.log(`<system cmd='${cmd}'>`);
	console.log(stdout);
	console.log('<system>');
  return stdout;
}
function certbot() {	
	const cmd = `certbot certonly --renew-by-default --webroot --webroot-path=/var/www/forum ${domains} --email=${email}`;
	const stdout = system(cmd);
	return stdout.split('\n').map(x=>x.trim()).filter(x=>x.startsWith('/etc/letsencrypt'));
}
[fullchain, privkey] = certbot();
//const dir = '/etc/letsencrypt/live/killtube.org-0005';
//[fullchain, privkey] = [dir + '/fullchain.pem', dir + '/privkey.pem'];
const cert    = privkey.replace('privkey', 'cert');
const chain   = privkey.replace('privkey', 'chain');
const lighttpd_chain   = privkey.replace('privkey', 'lighttpd_chain');
console.log(`const fullchain = '${fullchain}';`);
console.log(`const privkey   = '${privkey  }';`);
console.log(`const cert      = '${cert     }';`);
// Lighttpd requires privkey_plus_cert.pem and chain.pem (not as a link, so read/save it)
const privkey_plus_cert = [privkey, cert].map(file_get_contents).join('');
console.log('privkey_plus_cert', privkey_plus_cert);
const privkey_plus_cert_filename = privkey.replace('privkey', 'privkey_plus_cert');
writeFileSync(privkey_plus_cert_filename, privkey_plus_cert);
writeFileSync(lighttpd_chain, file_get_contents(chain));
// screen -r lighttpd
// ctrl+c
// arrow up + enter
system('pkill lighttpd');
system('screen -S lighttpd -X quit');
system('screen -AmdS lighttpd');
system('screen -S lighttpd -p 0 -X stuff "cd ~/KILLTUBE/^M"');
system('screen -S lighttpd -p 0 -X stuff "./lighttpd.sh^M"');
It all works so far, lets see in a month :^)