def run_domain_checks(rounded_time, env, output, pool):
	# Get the list of domains we handle mail for.
	mail_domains = get_mail_domains(env)

	# Get the list of domains we serve DNS zones for (i.e. does not include subdomains).
	dns_zonefiles = dict(get_dns_zones(env))
	dns_domains = set(dns_zonefiles)

	# Get the list of domains we serve HTTPS for.
	web_domains = set(get_web_domains(env))

	domains_to_check = mail_domains | dns_domains | web_domains

	# Get the list of domains that we don't serve web for because of a custom CNAME/A record.
	domains_with_a_records = get_domains_with_a_records(env)

	ssl_certificates = get_ssl_certificates(env)

	# Serial version:
	#for domain in sort_domains(domains_to_check, env):
	#	run_domain_checks_on_domain(domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains)

	# Parallelize the checks across a worker pool.
	args = ((domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains, domains_with_a_records, ssl_certificates)
		for domain in domains_to_check)
	ret = pool.starmap(run_domain_checks_on_domain, args, chunksize=1)
	ret = dict(ret) # (domain, output) => { domain: output }
	for domain in sort_domains(ret, env):
		ret[domain].playback(output)

def run_domain_checks(rounded_time, env, output, pool):
    # Get the list of domains we handle mail for.
    mail_domains = get_mail_domains(env)

    # Get the list of domains we serve DNS zones for (i.e. does not include subdomains).
    dns_zonefiles = dict(get_dns_zones(env))
    dns_domains = set(dns_zonefiles)

    # Get the list of domains we serve HTTPS for.
    web_domains = set(get_web_domains(env) + get_default_www_redirects(env))

    domains_to_check = mail_domains | dns_domains | web_domains

    # Serial version:
    # for domain in sort_domains(domains_to_check, env):
    # 	run_domain_checks_on_domain(domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains)

    # Parallelize the checks across a worker pool.
    args = (
        (domain, rounded_time, env, dns_domains, dns_zonefiles, mail_domains, web_domains)
        for domain in domains_to_check
    )
    ret = pool.starmap(run_domain_checks_on_domain, args, chunksize=1)
    ret = dict(ret)  # (domain, output) => { domain: output }
    for domain in sort_domains(ret, env):
        ret[domain].playback(output)

def starmap_parallel(function, values, number_of_processes=None, chunksize=1):
    assert callable(function)

    logger.debug('Creating multiprocessing pool with {} processes and chunksize {}.'.format(number_of_processes, chunksize))

    with multiprocessing.pool.Pool(processes=number_of_processes) as pool:
        results = pool.starmap(function, values, chunksize=chunksize)
        results = tuple(results)

    logger.debug('Parallel calculation with {} results completed.'.format(len(results)))

    return results

def run_services_checks(env, output, pool):
    # Check that system services are running.
    all_running = True
    fatal = False
    ret = pool.starmap(check_service, ((i, service, env) for i, service in enumerate(get_services())), chunksize=1)
    for i, running, fatal2, output2 in sorted(ret):
        if output2 is None: continue  # skip check (e.g. no port was set, e.g. no sshd)
        all_running = all_running and running
        fatal = fatal or fatal2
        output2.playback(output)

    if all_running:
        output.print_ok("All system services are running.")

    return not fatal

def run_services_checks(env, output, pool):
	# Check that system services are running.

	services = [
		{ "name": "Local DNS (bind9)", "port": 53, "public": False, },
		#{ "name": "NSD Control", "port": 8952, "public": False, },
		{ "name": "Local DNS Control (bind9/rndc)", "port": 953, "public": False, },
		{ "name": "Dovecot LMTP LDA", "port": 10026, "public": False, },
		{ "name": "Postgrey", "port": 10023, "public": False, },
		{ "name": "Spamassassin", "port": 10025, "public": False, },
		{ "name": "OpenDKIM", "port": 8891, "public": False, },
		{ "name": "OpenDMARC", "port": 8893, "public": False, },
		{ "name": "Memcached", "port": 11211, "public": False, },
		{ "name": "Mail-in-a-Box Management Daemon", "port": 10222, "public": False, },

		{ "name": "SSH Login (ssh)", "port": get_ssh_port(), "public": True, },
		{ "name": "Public DNS (nsd4)", "port": 53, "public": True, },
		{ "name": "Incoming Mail (SMTP/postfix)", "port": 25, "public": True, },
		{ "name": "Outgoing Mail (SMTP 587/postfix)", "port": 587, "public": True, },
		#{ "name": "Postfix/master", "port": 10587, "public": True, },
		{ "name": "IMAPS (dovecot)", "port": 993, "public": True, },
		{ "name": "Mail Filters (Sieve/dovecot)", "port": 4190, "public": True, },
		{ "name": "HTTP Web (nginx)", "port": 80, "public": True, },
		{ "name": "HTTPS Web (nginx)", "port": 443, "public": True, },
	]

	all_running = True
	fatal = False
	ret = pool.starmap(check_service, ((i, service, env) for i, service in enumerate(services)), chunksize=1)
	for i, running, fatal2, output2 in sorted(ret):
		if output2 is None: continue # skip check (e.g. no port was set, e.g. no sshd)
		all_running = all_running and running
		fatal = fatal or fatal2
		output2.playback(output)

	if all_running:
		output.print_ok("All system services are running.")

	return not fatal