Administering Diskless Nodes

There is no apparent difference between working on a diskless node and a disked node.

However, before you can use a diskless node, you must configure the node and start the processes that support the diskless node's operation. The following subsections describe the rules and techniques for managing diskless nodes and their partners. The last subsection describes a procedure for configuring a diskless node's partner.

3.11.1 Diskless Node Operation

When a diskless node displays the log-in prompt, all the programs required for its opera-tion are in place. While Using Your BSD Environment gives a complete descripopera-tion of disk-less node bootstrap operation, the following summary indicates what happens after you power on a diskless node in NORMAL mode.

1. The diskless node's Mnemonic Debugger broadcasts a message requesting a

volun-teer disked node partner. .

2. Each disked node running the netman program listens for such a "request for vol-unteer" broadcast. The disked node answers the request if the requester's hexa-decimal node ID is in the disked node's Isys/net/diskless_list file.

3. The diskless node loads netboot, its version of the operating system boot program from the partner, and proceeds with the bootstrap operation.

4. If the Ilpartnerisys/node_data.diskless_node_id directory does not exist, for exam-ple, if the diskless node has never booted from this partner, the netman program creates the directory and copies the node startup[.type] file from the

Isys/dm/startup_templates directory.

5. The diskless node's DM executes the commands in the I Ipartnerlsys/node_ data. diskless _node _idlstartup [. type] file.

6. The diskless node runs in the same manner as a disked node, using the partner node's disk for its system software.

3.11.2 Establishing Diskless Nodes and Their Partners

A diskless node's partner node provides the system software and disk services for the disk-less node. The partner does not necessarily store any of the diskdisk-less node user's files. Each partner node must run the diskless node server, netman. Partners can be nodes with, or without displays. Nodes without displays are DSPs.

A partner node must have the correct system software for the diskless node type. For ex-ample, if the diskless node is a DN570 and the partner node is a DSP90, the partner node must have both a Isau3 directory and a Isau5 directory. Similarly, the partner's Isys direc-tory must have any microcode files required by the diskless node.

Each diskless node has its own Isys/node_data.diskless_node_id directory on the partner node. The 'node_data directory on each diskless node resolves to the directory

Isys/node_data.diskless_node_id. If you change diskless node partner assignments, delete the Isys/node_data.diskless_node_id directory from the original partner's Isys directory.

The home directories of diskless node users can be located on any node in the network, and do not have to be on the diskless node's partner node. Whenever possible, locate the home directories on the same loop as the diskless node. If a diskless node has one or more regular users, their personal log-in start-up scripts, user_data/startup_dm [.type], should be in their home directories.

Specifying Partners

A disked node can be a partner to one or more diskless nodes. You control the assign-ment of diskless nodes to partners through the disked node's Isys/net/diskless_list file, such as the one shown in Figure 3-9. The disked node will volunteer to be a partner for any diskless node whose node ID is in the disked node's diskless_list.

# This is the diskless list for the network server on node 6b2d.

#

# The first token in each line of this file is examined by net man

# when it receives a network bootstrap volunteer request. If the

# token is a valid node ID, then netman will volunteer to help

# that node when it calls. Lines that do not begin with a valid

# node ID will be ignored. The use of the comment line

# character "#" is recommended.

#

# The nodes that this file authorizes netman to volunteer help for

# are:

3f4 eff2!

4d76

Figure 3-9. A Sample Isyslnetldiskless_list File

Choose the partners for diskless nodes carefully. For example, a partner should be in the same network loop as the diskless node; then, if you switch the loop out of the rest of the network, the diskless node can still function.

3-30 Administering Nodes in the Network

NOTES: If you put a diskless node's node ID on more than one diskless list, you cannot predict which node will become the partner when the diskless node boots. As a result, the diskless node's 'node_data directory and the contents of that directory, could change whenever the node reboots. Therefore, you must config-ure the diskless node correctly on each possible partner node.

If you use names for diskless nodes, do not change the name of the Isys/node_data.diskless_node_id directory to Isysl nOde_data.diskless_node_name. Remember, a diskless node name is not valid in a pathname. You must specify the diskless node ID to accurately access this object.

When you boot a diskless node, you can request a specific part-ner node. See "Requesting a Specific Partpart-ner," later in this sec-tion.

The Isys/node_data.node_id Directory on New Partners

If a diskless node's partner does not have a Isys/node_data.node_id directory when the diskless node boots using the partner, netman automatically creates one. If this directory does not contain the minimal set of files required by the diskless node to operate, netman creates them. The netman process also copies the startup[.type] file from the partner's Isys/dm/startup_templates or Isys/spm/startup_templates directory.

Providing a New Partner for a Diskless Node

Use Procedure 3-1 to configure a partner for a new node, change a partner for an existing node, or to provide an additional partner for an existing node. If a service representative installs a diskless node, he or she creates a partner for the node; you might want to use a different partner.