Set static BMC IP using different IP address (recommended)¶

The following example outlines the MTMS based hardware discovery for a single IPMI-based compute node.

Compute Node Information	Value
Model Type	8247-22l
Serial Number	10112CA
Hostname	cn01
IP address	10.1.2.1

The BMC IP address is obtained by the open range dhcp server and the plan in this scenario is to change the IP address for the BMC to a static IP address in a different subnet than the open range addresses. The static IP address in this example is in the same subnet as the open range to simplify the networking configuration on the xCAT management node.

BMC Information	Value
IP address - dhcp	172.30.0.1
IP address - static	172.20.2.1

Detect the BMCs and add the node definitions into xCAT.

Use the bmcdiscover command to discover the BMCs responding over an IP range and automatically write the output into the xCAT database. You must use the -w option to automatically write the output into the xCAT database.

To discover the BMC with an IP address of 172.30.0.1, use the command:
```
bmcdiscover --range 172.30.0.1 -z -w
```
The discovered nodes will be written to xCAT database:
```
# lsdef node-8247-22l-10112ca
Object name: node-8247-22l-10112ca
    bmc=172.30.0.1
    cons=ipmi
    groups=all
    hwtype=bmc
    mgt=ipmi
    mtm=8247-22L
    nodetype=mp
    postbootscripts=otherpkgs
    postscripts=syslog,remoteshell,syncfiles
    serial=10112CA
    nodetype=mp
```
Pre-define the compute nodes:

Use the bmcdiscover command to help discover the nodes over an IP range and easily create a starting file to define the compute nodes into xCAT.

To discover the compute nodes for the BMCs with an IP address of 172.30.0.1, use the command:
```
bmcdiscover --range 172.30.0.1 -z > predefined.stanzas
```
The discovered nodes have the naming convention: node-<model-type>-<serial-number>
```
# cat predefined.stanzas
node-8247-22l-10112ca:
  objtype=node
  groups=all
  bmc=172.30.0.1
  cons=ipmi
  mgt=ipmi
  mtm=8247-22L
  serial=10112CA
```
Edit the predefined.stanzas file and change the discovered nodes to the intended hostname and IP address.
1. Edit the predefined.stanzas file:
  vi predefined.stanzas
2. Rename the discovered object names to their intended compute node hostnames based on the MTMS mapping:
  node-8247-22l-10112ca ==> cn01
3. Add a ip attribute and give it the compute node IP address:
  ip=10.1.2.1
4. Remove nodetype and hwtype if defined in the predefined.stanza.
5. Repeat for additional nodes in the predefined.stanza file based on the MTMS mapping.
In this example, the predefined.stanzas file now looks like the following:
# cat predefined.stanzas cn01: objtype=node groups=all bmc=172.30.0.1 cons=ipmi mgt=ipmi mtm=8247-22L serial=10112CA ip=10.1.2.1
Set the chain table to run the bmcsetup script, this will set the BMC IP to static.
```
chdef cn01 chain="runcmd=bmcsetup"
```
Set the target osimage into the chain table to automatically provision the operating system after the node discovery is complete.
```
chdef cn01 -p chain="osimage=<osimage_name>"
```
Change the BMC IP address

Set the BMC IP address to a different value for the predefined compute node definitions.

To change the dhcp obtained IP address of 172.30.0.1 to a static IP address of 172.20.2.1, run the following command:
```
chdef cn01 bmc=172.20.2.1
```
Define the compute nodes into xCAT:
```
cat predefined.stanzas | mkdef -z
```
Add the compute node IP information to /etc/hosts:
```
makehosts cn01
```
Refresh the DNS configuration for the new hosts:
```
makedns -n
```
[Optional] Monitor the node discovery process using rcons

Configure the conserver for the discovered node to watch the discovery process using rcons:
```
makeconservercf node-8247-22l-10112ca
```
In another terminal window, open the remote console:
```
rcons node-8247-22l-10112ca
```

Start the discovery process by booting the discovered node definition:

rsetboot node-8247-22l-10112ca net
rpower node-8247-22l-10112ca on

The discovery process will network boot the machine into the diskless xCAT genesis kernel and perform the discovery process. When the discovery process is complete, doing lsdef on the compute nodes should show discovered attributes for the machine. The important mac information should be discovered, which is necessary for xCAT to perform OS provisioning.