8

Nodes

• Introducing nodes
• Configuration options

Introducing nodes

Nodes are the network devices to which the BIG-IP system passes traffic. A network device becomes a node when it is added as a member to a load balancing pool. You can display information about nodes and set properties for nodes, using either the Configuration utility or the bigpipe node command.

Configuration options

The attributes you can configure for a node are listed in Table 8.1 .

The following sections describe the procedures for configuring these options.

Enabling and disabling nodes and node addresses

A node must be enabled in order to accept traffic. When a node is disabled, it allows existing connections to time out or end normally, and accept new connections only if they belong to an existing persistence session. (In this way a disabled node differs from a node that is set down. The down node allows existing connections to time out, but accepts no new connections.)

To enable and disable nodes and node addresses

To enable a node or node address, use the bigpipe node command with the enable option:

b node 192.168.21.1 enable

To disable a node or node address, use the bigpipe node command with the disable option:

b node 192.168.21.1 disable

Marking nodes and node ports as up or down

A node must be marked up in order to accept traffic. When a node is marked down it allows existing connections to time out but accepts no new connections.

To mark nodes and node ports up or down using the Configuration utility

1. In the navigation pane, click Nodes.
   The Nodes screen opens.
2. In the list of nodes, click a node address.
   The properties page for that node opens.
3. To mark a node as down, clear the Enable Connections check box. To mark a node as up, click the Enable Connections check box.
4. Click Apply.

To mark nodes and node ports up or down from the command line

To mark a node as down, specify the bigpipe node command with a node address and the down option. (Note that marking a node down prevents the node from accepting new connections. Existing connections are allowed to complete.) For example:

b node 192.168.21.1 dow

To mark a node as up, use the bigpipe node command with the up option. For example:

b node 192.168.21.1 up

To mark a particular service as down, specify the bigpipenode command with a node address and port, and the down option. (Note that marking a service as down prevents the service from accepting new connections. Existing connections are allowed to complete.) For example:

b node 192.168.21.1:80 down

To mark a particular service as up, use the bigpipe node command with up option. For example:

b node 192.168.21.1:80 up

Note

Setting connection limits for nodes

Using the Configuration utility or the bigpipe node command, you can limit the number of concurrent connections that a node will allow.

To set connection limits for nodes using the Configuration utility

1. In the navigation pane, click Nodes.
   The Nodes screen opens.
2. In the list of nodes, click a node address.
   The properties page for that node opens.
3. In the Connection Limit box, type a number representing the maximum concurrent connections allowed on a node.
4. Click Apply.

To set connection limits for nodes from the command line

Use the following command to set the maximum number of concurrent connections allowed on a node:

b node <node_ip>[:<service>][...<node_ip>[:<service>]] limit <max conn>

Note that to remove a connection limit, set the <max conn> variable to 0 (zero). For example:

b node 192.168.21.1:80 limit 0

The following example shows how to set the maximum number of concurrent connections to 100 for a list of nodes:

b node 192.168.21.1 192.168.21.1 192.168.21.1 limit 100

To remove a connection limit, set the <max conn> variable to 0 (zero).

Associating monitors with nodes

To implement a health or performance monitor, you must associate that monitor with a node.

To associate a monitor with a node

Use the following command line syntax to associate a monitor with a node:

b node <node> monitor use <monitor>

A monitor can be placed on multiple nodes, and a node can have multiple monitors placed on it.

To associate a monitor with multiple nodes:

b node <node_list> monitor use <monitor>

To associate multiple monitors with a node:

b node <node> monitor use <monitor1> and <monitor2>...

For more information on using the bigpipe node command with monitors, refer to Chapter 12, Monitors .

Displaying node status

When you issue the bigpipe node show command, the BIG-IP system displays the node status (up or down, or unchecked), and a node summary of connection statistics, which is further broken down to show statistics by service.

To display status of all nodes using the Configuration utility

In the navigation pane, click Nodes. The Nodes screen opens and displays the status of all nodes.

To display status of all nodes from the command line

To display the status of a node from the command line, type the following command:

b node show

The report shows the following information:

• Current number of connections
• Total number of connections made to the node since last boot
• Maximum number of concurrent connections since the last boot
• Concurrent connection limit on the node
• The total number of connections made to the node since last boot
• Total number of inbound and outbound packets and bits

Figure 8.1 shows the output of this command.

To display the status of individual nodes and node addresses

Use the following command to display status and statistical information for one or more node addresses:

b node 192.168.21.1 show

The command reads the status of each node address, the number of current connections, total connections, and connections allowed, and the number of cumulative packets and bits sent and received.

Use the following command to display status and statistical information for one or more specific nodes:

b node 192.168.21.1:80 show

Resetting node statistics

You can reset statistics for an individual node address. To do this, use the following command line syntax:

b node [<node_ip>:<service>] stats reset

Adding nodes to pools

You can add a node as a member of a load balancing pool. For more information, see Chapter 4, Pools .