[SR-Users] Kazoo like load balancing

Daniel Tryba d.tryba at pocos.nl
Tue Jul 21 12:12:18 CEST 2015


On Tuesday 21 July 2015 12:45:02 Jurijs Ivolga wrote:
> Maybe you can share with me full config of your load-balancer? It will be
> really nice if I can take a look on it. I'm very new in kamailio and for me
> is very difficult to complile working config from short code snippets. :)

See attachment. It is essentially the default config with some shortcuts for 
nat detection based on subnet and path support added.

> You mentioned that you have 2 load-balancer. Does this 2 load-balancers
> share one domain-name?

Yes. The idea is that:
-smart user agents can use SRV DNS records to do failover
-not so smart user agents use the A DNS record (short ttl, maybe round robin)
-stupid user agents use the ip adress of a loadbalancer by default and the 
other as backup

The actual domain is rewritten before sending to backends.

> I was thinking to use dispatcher module for load balancing. Do you use
> dispatcher module in your config?

Yes, you need to loadbalance with dispatcher that the same callid is always 
routed to the same backend server.

-------------- next part --------------
#!KAMAILIO
#
# Kamailio (OpenSER) SIP Server v4.2 - default configuration script
#     - web: http://www.kamailio.org
#     - git: http://sip-router.org
#
# Direct your questions about this file to: <sr-users at lists.sip-router.org>
#
# Refer to the Core CookBook at http://www.kamailio.org/wiki/
# for an explanation of possible statements, functions and parameters.
#
# Several features can be enabled using '#!define WITH_FEATURE' directives:
#
# *** To run in debug mode: 
#     - define WITH_DEBUG
#
# *** To enable mysql: 
#     - define WITH_MYSQL
#
# *** To enable authentication execute:
#     - enable mysql
#     - define WITH_AUTH
#     - add users using 'kamctl'
#
# *** To enable IP authentication execute:
#     - enable mysql
#     - enable authentication
#     - define WITH_IPAUTH
#     - add IP addresses with group id '1' to 'address' table
#
# *** To enable persistent user location execute:
#     - enable mysql
#     - define WITH_USRLOCDB
#
# *** To enable presence server execute:
#     - enable mysql
#     - define WITH_PRESENCE
#
# *** To enable nat traversal execute:
#     - define WITH_NAT
#     - install RTPProxy: http://www.rtpproxy.org
#     - start RTPProxy:
#        rtpproxy -l _your_public_ip_ -s udp:localhost:7722
#     - option for NAT SIP OPTIONS keepalives: WITH_NATSIPPING
#
# *** To enable PSTN gateway routing execute:
#     - define WITH_PSTN
#     - set the value of pstn.gw_ip
#     - check route[PSTN] for regexp routing condition
#
# *** To enable database aliases lookup execute:
#     - enable mysql
#     - define WITH_ALIASDB
#
# *** To enable speed dial lookup execute:
#     - enable mysql
#     - define WITH_SPEEDDIAL
#
# *** To enable multi-domain support execute:
#     - enable mysql
#     - define WITH_MULTIDOMAIN
#
# *** To enable TLS support execute:
#     - adjust CFGDIR/tls.cfg as needed
#     - define WITH_TLS
#
# *** To enable XMLRPC support execute:
#     - define WITH_XMLRPC
#     - adjust route[XMLRPC] for access policy
#
# *** To enable anti-flood detection execute:
#     - adjust pike and htable=>ipban settings as needed (default is
#       block if more than 16 requests in 2 seconds and ban for 300 seconds)
#     - define WITH_ANTIFLOOD
#
# *** To block 3XX redirect replies execute:
#     - define WITH_BLOCK3XX
#
# *** To enable VoiceMail routing execute:
#     - define WITH_VOICEMAIL
#     - set the value of voicemail.srv_ip
#     - adjust the value of voicemail.srv_port
#
# *** To enhance accounting execute:
#     - enable mysql
#     - define WITH_ACCDB
#     - add following columns to database
#!ifdef ACCDB_COMMENT
  ALTER TABLE acc ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT '';
  ALTER TABLE acc ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT '';
  ALTER TABLE acc ADD COLUMN src_ip varchar(64) NOT NULL default '';
  ALTER TABLE acc ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT '';
  ALTER TABLE acc ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT '';
  ALTER TABLE acc ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT '';
  ALTER TABLE missed_calls ADD COLUMN src_user VARCHAR(64) NOT NULL DEFAULT '';
  ALTER TABLE missed_calls ADD COLUMN src_domain VARCHAR(128) NOT NULL DEFAULT '';
  ALTER TABLE missed_calls ADD COLUMN src_ip varchar(64) NOT NULL default '';
  ALTER TABLE missed_calls ADD COLUMN dst_ouser VARCHAR(64) NOT NULL DEFAULT '';
  ALTER TABLE missed_calls ADD COLUMN dst_user VARCHAR(64) NOT NULL DEFAULT '';
  ALTER TABLE missed_calls ADD COLUMN dst_domain VARCHAR(128) NOT NULL DEFAULT '';
#!endif

####### Include Local Config If Exists #########
import_file "kamailio-local.cfg"

####### Defined Values #########

# *** Value defines - IDs used later in config
#!ifdef WITH_MYSQL
# - database URL - used to connect to database server by modules such
#       as: auth_db, acc, usrloc, a.s.o.
#!ifndef DBURL
#!define DBURL "mysql://kamailio:kamailiorw@localhost/kamailio"
#!endif
#!endif
#!ifdef WITH_MULTIDOMAIN
# - the value for 'use_domain' parameters
#!define MULTIDOMAIN 1
#!else
#!define MULTIDOMAIN 0
#!endif

# - flags
#   FLT_ - per transaction (message) flags
#	FLB_ - per branch flags
#!define FLT_ACC 1
#!define FLT_ACCMISSED 2
#!define FLT_ACCFAILED 3
#!define FLT_NATS 5

#!define FLB_NATB 6
#!define FLB_NATSIPPING 7

####### Global Parameters #########

### LOG Levels: 3=DBG, 2=INFO, 1=NOTICE, 0=WARN, -1=ERR
#!ifdef WITH_DEBUG
debug=4
log_stderror=yes
#!else
debug=2
log_stderror=no
#!endif

memdbg=5
memlog=5

log_facility=LOG_LOCAL0

fork=yes
children=4

/* uncomment the next line to disable TCP (default on) */
#disable_tcp=yes

/* uncomment the next line to disable the auto discovery of local aliases
   based on reverse DNS on IPs (default on) */
#auto_aliases=no

/* add local domain aliases */
alias="sip.pocos-voip.nl"
alias="109.235.32.240"

/* uncomment and configure the following line if you want Kamailio to 
   bind on a specific interface/port/proto (default bind on all available) */
#listen=udp:10.0.0.10:5060

/* port to listen to
 * - can be specified more than once if needed to listen on many ports */
port=5060

#!ifdef WITH_TLS
enable_tls=yes
#!endif

# life time of TCP connection when there is no traffic
# - a bit higher than registration expires to cope with UA behind NAT
tcp_connection_lifetime=3605

####### Custom Parameters #########

# These parameters can be modified runtime via RPC interface
# - see the documentation of 'cfg_rpc' module.
#
# Format: group.id = value 'desc' description
# Access: $sel(cfg_get.group.id) or @cfg_get.group.id
#

####### Modules Section ########

# set paths to location of modules (to sources or installation folders)
#!ifdef WITH_SRCPATH
mpath="modules/"
#!else
mpath="/usr/lib/x86_64-linux-gnu/kamailio/modules/"
#!endif

#!ifdef WITH_MYSQL
loadmodule "db_mysql.so"
#!endif

loadmodule "mi_fifo.so"
loadmodule "kex.so"
loadmodule "corex.so"
loadmodule "tm.so"
loadmodule "tmx.so"
loadmodule "sl.so"
loadmodule "rr.so"
loadmodule "pv.so"
loadmodule "maxfwd.so"
loadmodule "usrloc.so"
loadmodule "registrar.so"
loadmodule "textops.so"
loadmodule "siputils.so"
loadmodule "xlog.so"
loadmodule "sanity.so"
loadmodule "ctl.so"
loadmodule "cfg_rpc.so"
loadmodule "mi_rpc.so"
loadmodule "ipops.so"

#!ifdef WITH_MULTIDOMAIN
loadmodule "domain.so"
#!endif

loadmodule "nathelper.so"

#!ifdef WITH_TLS
loadmodule "tls.so"
#!endif

loadmodule "htable.so"
#!ifdef WITH_ANTIFLOOD
loadmodule "pike.so"
#!endif

#!ifdef WITH_DEBUG
loadmodule "debugger.so"
#!endif

loadmodule "path.so"
loadmodule "dispatcher.so"

# ----------------- setting module-specific parameters ---------------

modparam("path", "use_received", 1)


# ----- dispatcher -----
modparam("dispatcher", "list_file", "/etc/kamailio/dispatcher.list")
modparam("dispatcher", "flags", 2)
modparam("dispatcher", "dst_avp", "$avp(AVP_DST)")
modparam("dispatcher", "grp_avp", "$avp(AVP_GRP)")
modparam("dispatcher", "cnt_avp", "$avp(AVP_CNT)")
modparam("dispatcher", "ds_ping_method", "OPTIONS");
modparam("dispatcher", "ds_ping_interval", 15);
modparam("dispatcher", "ds_probing_mode", 1);
modparam("dispatcher", "ds_ping_from", "sip:loadbalancer at 109.235.32.240");


# ----- mi_fifo params -----
modparam("mi_fifo", "fifo_name", "/tmp/kamailio_fifo")


# ----- tm params -----
# auto-discard branches from previous serial forking leg
modparam("tm", "failure_reply_mode", 3)
# default retransmission timeout: 30sec
modparam("tm", "fr_timer", 30000)
# default invite retransmission timeout after 1xx: 120sec
modparam("tm", "fr_inv_timer", 120000)


# ----- rr params -----
# set next param to 1 to add value to ;lr param (helps with some UAs)
modparam("rr", "enable_full_lr", 0)
# do not append from tag to the RR (no need for this script)
modparam("rr", "append_fromtag", 0)


# ----- registrar params -----
modparam("registrar", "method_filtering", 1)
/* uncomment the next line to disable parallel forking via location */
# modparam("registrar", "append_branches", 0)
/* uncomment the next line not to allow more than 10 contacts per AOR */
#modparam("registrar", "max_contacts", 10)
# max value for expires of registrations
modparam("registrar", "max_expires", 3600)
# set it to 1 to enable GRUU
modparam("registrar", "gruu_enabled", 0)


# ----- usrloc params -----
/* enable DB persistency for location entries */
#!ifdef WITH_USRLOCDB
modparam("usrloc", "db_url", DBURL)
modparam("usrloc", "db_mode", 2)
modparam("usrloc", "use_domain", MULTIDOMAIN)
#!endif

# ----- domain params -----
#!ifdef WITH_MULTIDOMAIN
modparam("domain", "db_url", DBURL)
# register callback to match myself condition with domains list
modparam("domain", "register_myself", 1)
#!endif

# ----- nathelper params -----
modparam("nathelper", "natping_interval", 30)
modparam("nathelper", "ping_nated_only", 1)
modparam("nathelper", "sipping_bflag", FLB_NATSIPPING)
modparam("nathelper", "sipping_from", "sip:pinger at kamailio.org")

# params needed for NAT traversal in other modules
modparam("nathelper|registrar", "received_avp", "$avp(RECEIVED)")
modparam("usrloc", "nat_bflag", FLB_NATB)


#!ifdef WITH_TLS
# ----- tls params -----
modparam("tls", "config", "/etc/kamailio/tls.cfg")
#!endif

#!ifdef WITH_ANTIFLOOD
# ----- pike params -----
modparam("pike", "sampling_time_unit", 2)
modparam("pike", "reqs_density_per_unit", 16)
modparam("pike", "remove_latency", 4)

# ----- htable params -----
# ip ban htable with autoexpire after 5 minutes
modparam("htable", "htable", "ipban=>size=8;autoexpire=300;")
#!endif


#!ifdef WITH_DEBUG
# ----- debugger params -----
modparam("debugger", "cfgtrace", 1)
modparam("debugger", "log_level_name", "exec")
#!endif

####### Routing Logic ########


# Main SIP request routing logic
# - processing of any incoming SIP request starts with this route
# - note: this is the same as route { ... }
request_route {
	route(NATDETECT);
	route(WITHINDLG);

	if (is_method("INVITE|SUBSCRIBE"))
	{
		record_route();
	}

	if(!is_in_subnet($si, "109.235.32.240/28"))
	{
		add_path_received("loadbalancer");
		$rd="sip.pocos-voip.nl";

		ds_select_dst(1, 0);
	        t_on_failure("RTF_DISPATCH");
	}
	else
	{
		add_path("cluster");

		remove_hf("Route");

		loose_route();
	}
	
	route(RELAY);
}

# Wrapper for relaying requests
route[RELAY] {

	# enable additional event routes for forwarded requests
	# - serial forking, RTP relaying handling, a.s.o.
	if (is_method("INVITE|BYE|SUBSCRIBE|UPDATE")) {
		if(!t_is_set("branch_route")) t_on_branch("MANAGE_BRANCH");
	}
	if (is_method("INVITE|SUBSCRIBE|UPDATE")) {
		if(!t_is_set("onreply_route")) t_on_reply("MANAGE_REPLY");
	}
	if (is_method("INVITE")) {
		if(!t_is_set("failure_route")) t_on_failure("MANAGE_FAILURE");
	}

	if (!t_relay()) {
		sl_reply_error();
	}
	exit;
}

# Per SIP request initial checks
route[REQINIT] {
#!ifdef WITH_ANTIFLOOD
	# flood dection from same IP and traffic ban for a while
	# be sure you exclude checking trusted peers, such as pstn gateways
	# - local host excluded (e.g., loop to self)
	if(src_ip!=myself) {
		if($sht(ipban=>$si)!=$null) {
			# ip is already blocked
			xdbg("request from blocked IP - $rm from $fu (IP:$si:$sp)\n");
			exit;
		}
		if (!pike_check_req()) {
			xlog("L_ALERT","ALERT: pike blocking $rm from $fu (IP:$si:$sp)\n");
			$sht(ipban=>$si) = 1;
			exit;
		}
	}
	if($ua =~ "friendly-scanner") {
		sl_send_reply("200", "OK");
		exit;
	}
#!endif

	if (!mf_process_maxfwd_header("10")) {
		sl_send_reply("483","Too Many Hops");
		exit;
	}

	if(is_method("OPTIONS") && uri==myself && $rU==$null) {
		sl_send_reply("200","Keepalive");
		exit;
	}

	if(!sanity_check("1511", "7")) {
		xlog("Malformed SIP message from $si:$sp\n");
		exit;
	}
}

# Handle requests within SIP dialogs
route[WITHINDLG] {
	if (!has_totag()) return;

	# sequential request withing a dialog should
	# take the path determined by record-routing
	if (loose_route()) {
		route(DLGURI);
		if (is_method("BYE")) {
			setflag(FLT_ACC); # do accounting ...
			setflag(FLT_ACCFAILED); # ... even if the transaction fails
		}
		else if ( is_method("ACK") ) {
			# ACK is forwarded statelessy
			route(NATMANAGE);
		}
		else if ( is_method("NOTIFY") ) {
			# Add Record-Route for in-dialog NOTIFY as per RFC 6665.
			record_route();
		}
		route(RELAY);
		exit;
	}

	if (is_method("SUBSCRIBE") && uri == myself) {
		# in-dialog subscribe requests
		exit;
	}
	if ( is_method("ACK") ) {
		if ( t_check_trans() ) {
			# no loose-route, but stateful ACK;
			# must be an ACK after a 487
			# or e.g. 404 from upstream server
			route(RELAY);
			exit;
		} else {
			# ACK without matching transaction ... ignore and discard
			exit;
		}
	}
	sl_send_reply("404","Not here");
	exit;
}

# Caller NAT detection
route[NATDETECT] {
	if(!is_in_subnet($si, "109.235.32.240/28"))
	{
		force_rport();

		if (is_method("REGISTER")) {
			fix_nated_register();
		} else {
			add_contact_alias();
		}
	}

	return;
}

# RTPProxy control and singaling updates for NAT traversal
route[NATMANAGE] {
	if(!is_in_subnet($si, "109.235.32.240/28"))
	{
		if (is_request()) {
			if(has_totag()) {
				if(check_route_param("nat=yes")) {
					setbflag(FLB_NATB);
				}
			}
		}

		if (is_request()) {
			if (!has_totag()) {
				add_rr_param(";nat=yes");
			}
		}
		if (is_reply()) {
			add_contact_alias();
		}
	}
	return;
}

# URI update for dialog requests
route[DLGURI] {
	if(!is_in_subnet($si, "109.235.32.240/28"))
	{
		add_path_received("loadbalancer");
	}
	else
	{
		add_path("cluster");
	}

	if(!isdsturiset()) {
		handle_ruri_alias();
	}
	return;
}

# Manage outgoing branches
branch_route[MANAGE_BRANCH] {
	xlog("L_ALERT","MANAGE_BRANCH: $rm from $fu (IP:$si:$sp) to $ru via $du\n");
	route(NATMANAGE);
}

# Manage incoming replies
onreply_route[MANAGE_REPLY] {
	xlog("L_ALERT","MANAGE_REPLY: $rm from $fu (IP:$si:$sp) to $ru via $du\n");
#	if(status=~"[12][0-9][0-9]")
		route(NATMANAGE);
}

# Manage failure routing cases
failure_route[MANAGE_FAILURE] {
	xlog("L_ALERT","MANAGE_FAILURE: $rm from $fu (IP:$si:$sp) to $ru via $du\n");
	route(NATMANAGE);

	if (t_is_canceled()) {
		exit;
	}

#!ifdef WITH_BLOCK3XX
	# block call redirect based on 3xx replies.
	if (t_check_status("3[0-9][0-9]")) {
		t_reply("404","Not found");
		exit;
	}
#!endif
}

failure_route[RTF_DISPATCH]
{
	xlog("L_ALERT","RTF_DISPATCH: $rm from $fu (IP:$si:$sp) to $ru\n");
	if (t_is_canceled()) {
		exit;
	}
# next DST - only for 500 or local timeout
	if (t_check_status("500") or (t_branch_timeout() and !t_branch_replied()))
	{
		if(ds_next_dst())
		{
			t_on_failure("RTF_DISPATCH");
			route(RELAY);
			exit;
		}
	}
}


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