LVSKB - User contributions [en]

Net-SNMP-LVS-Module

2010-01-20T21:13:09Z

Gam3: extra comma

== GENERAL ==
net-snmpd-lvs-module is a dynamicaly loadable shared object for SNMP to get the configuration and some statistical information from the Linux kernel with [[IPVS|IP virtual server]] support.

== INSTALLATION ==
Get the source for this module ([[media:Net-snmp-lvs-module-0.0.4.tar.gz|local copy]] or [http://www.loadbalancer.org/download/SNMP/net-snmp-lvs-module-0.0.4.tar.gz Alternate source location]). From http://www.linuxvirtualserver.org/software/ipvs.html download the the correct version of ipvsadm, for kernel 2.6 use ipvsadm-1.24 or later, for kernel 2.4 use ipvsadm-1.21. Extract '''ipvsadm-''version''.tar.gz''', build the library and copy the subtree '''libipvs''' into the module's working directory.

Check that the Linux kernel is available under '''/usr/src/linux'''. Install net-snmp and its development headers and libraries. Invoke '''make''', this should build '''lvs.so'''. Copy LVS-MIB.txt and OC-MIB.txt to '''/usr/share/snmp/mibs/'''.

Check that the new MIB is visible by invoking
shell> snmptranslate -m LVS-MIB -On -IR lvsServiceEntry
this should return '''.1.3.6.1.4.1.8225.4711.18.1'''
Copy '''lvs.so''' to '''/usr/lib/libnetsnmplvs.so''' and add the following line to
'''/etc/snmp/snmpd.conf''':
dlmod lvs /usr/lib/libnetsnmplvs.so
Restart your snmpd.

Try if everything works invoking:
shell> snmpwalk -c public -v 2c -m LVS-MIB localhost 1.3.6.1.4.1.8225.4711
LVS-MIB::lvsVersion.0 = STRING: "1.2.0"
LVS-MIB::lvsNumServices.0 = INTEGER: 2
LVS-MIB::lvsHashTableSize.0 = INTEGER: 4096
LVS-MIB::lvsTcpTimeOut.0 = INTEGER: 900
LVS-MIB::lvsTcpFinTimeOut.0 = INTEGER: 120
LVS-MIB::lvsUdpTimeOut.0 = INTEGER: 300
LVS-MIB::lvsDaemonState.0 = INTEGER: none(0)
...

In case you want to add additional snmp-values to your MIB:
Set export MIBS=ALL and create skeleton with
shell> mib2c -c mib2c.interate.conf lvsRealTable
or
shell> mib2c -c mib2c.interate.conf lvsServiceTable
this should create a file '''lvsRealTable.c''' and/or '''lvsServiceTable.c'''.
Use the generated code as a template for '''lvs.c''' and populate the missing parts.

== Troubleshooting ==
If you find an output for <tt></tt> like this:
[root@machine ~]# snmpwalk -c public -v 2c -m LVS-MIB localhost 1.3.6.1.4.1.8225.4711
LVS-MIB::lvs = No more variables left in this MIB View (It is past the end of the MIB tree)

I found the solution to be [quite] less conservative with <tt>snmpd.conf</tt> [http://www.esn.ae.krakow.pl/~mike/Other/lvs-snmp/ here]:

«''You can add following lines to snmpd.conf ('+' marks which line was added). This is an example and you should be very careful in granting access to your snmp coz potentially it can be a security issue:''»

+view all included .1
view systemview included .1.3.6.1.2.1.1

+access notConfigGroup "" any noauth exact all none none
access notConfigGroup "" any noauth exact systemview none none

This was verified in CentOS 5.2.

== CREDITS ==
The code for this module currently is maintained by Jacob Rief. This code is based on ucd-snmpd-lvs written by Romeo Benzoni in 2002 and never modified since. As that code did not compile with the newer net-snmp headers, I decided to rewrite the complete code. The only unchanged parts from the ucd-snmpd-lvs project are LVS-MIB.txt and OC-MIB.txt.

== Extrenal Links ==
The official site does not exist any more, since I left that company.
If somebody gives me access to the repository, I will maintain the module there, otherwise I will have to create one at Google-code.

[[Category:LVS Software]]

User:Gam3

2008-05-12T16:19:49Z

Gam3:

G. Allen Morris III

[http://heavener.gam3.net/ heavener]

Troubleshooting

2006-02-28T23:13:56Z

Gam3:

== Introduction ==

In order to make troubleshooting easier, we need to understand the IP load balancing technology that we are using now in the cluster, and know the whole packet flow, such as how packets are received and sent out at the [[load balancer]], and how packets are handled at real servers and sent out back to the clients.

To know more information about IP load balacing technologies implemented in the IPVS, check
* [[LVS/NAT | Virtual Server via Network Address Transaltion]]
* [[LVS/TUN | Virtual Server via IP Tunneling]]
* [[LVS/DR | Virtual Server via Direct Routing]]

Then, we can use some packet capture tools, such as [[ethereal]] and [[tcpdump]], to do troubleshooting at our cluster system. First, we can capture the load balanced traffic at both [[load balancer]] and real servers, in order to make sure that basic load balancing system works; Second, we can also capture packets of service monitoring among load balancers and real servers, to verify that cluster monitoring and high availability works as expected.

== Load Balancer ==

== Real Server ==

== Troubleshooting Examples ==

While LVS provides basic means for load-balancing, [[lvs-kiss]] provides some more sophisticated possibilities.

Basically [[lvs-kiss]] is just a peace of pearl that sits on top of LVS.

[[lvs-kiss]] features configurable means of measuring node "load". This can be anything - from using the average load to an snmp-get (any thing you can imagine doing at the command-line of an lvs-server which gives a numerical response).

Trouble-shooting load-balancing can be tricky, when you encounter web-caches etc. I tend to use the good old "telnet VIP PORT" to check the result of load-balancing. For tests, you may even use dummy results with [[lvs-kiss]] (just do "echo NUMBER" as method for getting the load...).

== Traps ==

If you compile linux without the CONFIG_IP_VS_PROTO_TCP configure option, ipvsadm does not give any error messages, but does not grab incoming connections.

User:Gam3

2006-02-28T00:22:26Z

Gam3: G. Allen Morris III

G. Allen Morris III

IPVS Wish List

2006-02-28T00:21:13Z

Gam3: /* Feature List */

This page is to write all the wishes for [[IPVS]] development.

'''Remember''': you can ask for features as long as you want, but that won't make such features appear magically. :) Basically, you have these options:
* get your hands dirty, program and submit code to LVS
* convince other programmers that your wanted feature is valuable to them so that the programmers do it for you (and the rest of the community)
* put some bounty on a feature development and wait until someone wants to earn some money

== Feature List ==

* [[SCTP load balancing]] support
* connection synchronization improvement
* ip_gre tunnel

[[Category:IPVS]]