STONITH module for WTI MPC
--------------------------


****Introduction.

wti_mpc module uses snmp for controlling the MPC power distribution unit. It has
been tested with MPC-8H and MPC-18H and should be compatible with the whole
MPC series:
    * MPC-20*
    * MPC-16*
    * MPC-18*
    * MPC-8*
    
****Unit configuration.
    
wti_mpc STONITH modules uses SNMP v1, therefore it should be configured on the 
device side. To do so, you should login to device, go to "Network 
configuration" (/N), select "SNMP access" (25) and turn it on (enable/1). At the
SNMP access screen set "Version" (2) to "V1/V2 Only", set "Read only" (3) to
"No and set any "Community" (10) you want. You may also set other options as
you need. You may check your setup by issuing the following command:

    snmpwalk -v1 -c <community> <host> .1.3.6.1.2.1.1.1.0

and result should be something like this:

    SNMPv2-MIB::sysDescr.0 = STRING: Linux 85.195.135.236 2.4.18_mvl30-cllf #1991 Sun Mar 16 14:39:29 PST 2008 ppc
    

****Plugin configuration.

    Plugin declares the following configuration variables:
    
    *ipaddr - 	   ip address or hostname of a MPC unit.
    *port   - 	   ip port, should be 161, as MPC listens for incoming SNMP 
		   packets on that port. It is made for future use actually.
    *community -   Community that you've specified on previous step.
    *mib_version - Should be 3 for MPC devices with firmware version 1.62
                   and later. 1 is for firmware version 1.44 and below.
                   2 is unused right now, if you have device, with mib V2 
                   feel free to contact me and I'll add it.
                   
****MIB version issue

    WTI guys have several time changed OIDs, used by MPC devices. I own two
types of the devices:
	*With firmware v 1.44 which is compatible with MIB version 1
	*With firmware v 1.62 which is compatible with MIB version 3
	
I suppose there are exist MIB v2, but i cannot find it and I'd not able 
to test it.
Anyway, this plugin supports both V1 and V3 versions, and the correct version 
is selected by the "mib-version" configuration parameter. Default value is "1",
so if you do not specify this parameter or assign a unsupported value to it,
it will fall back to mib version 1.

****Outlets and groups

    MPC devices forces unique names of the outlets. This is a big problem 
for STONITH plugin, cause it uses nodes unames as outlet names, so in case
you have a node with several power plugs, you should have set the node uname
as name of all the plugs. The MPC device simply doesn't allows this. 
    So, this plugin works with a GROUPS instead of a PLUGS. You may give
any unique names for your physical outlets on the MPC, but you MUST create
a plug group, name it using node's uname and include plugs, corresponding to
that particular node to this group. It should be done even for node with
single power supply. Some example:

    Let's pretend you have a node "atest", with two power cords, connected
to plugs A1 and B1. You have to create a group ("Plug grouping parameters" (/G)
-> Add Plug Group to directory (2)), name it "atest" ("Plug Group Name (1)) and
assign plugs A1 and B1 to that group ("Plug access" (2)). Now save your
configuration and try to retrieve host list:

     stonith -t wti_mpc ipaddr=<host> port=161 community=<community>  mib-version=<version> -l

result should be: 
    
    atest
    

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(C) Denis Chapligin <chollya@satgate.net>, SatGate, 2009