# Flight Hunter

Flight hunter is a MAC collection tool that is used within the flight user suite to manage, find and connect to nodes in a compute cluster. It is predominantly used while setting up a cluster.

Flight hunter's namesake feature is the ability to discover nodes on the local network by hunting. It can also send information between nodes, and can send on startup to a designated server node.

Hunting can be started with the command flight hunter hunt. e.g.

[flight@chead1 (mycluster1) [login1] ~]$ flight hunter hunt
Hunter running on port 8888 - Ctrl+C to stop

There are several options that change how hunt works:

• --allow-existing - Duplicate entries will replace existing ones rather than being rejected.
• --port <port> - Overrides the default port to accept on.
• --include-self - Sends itself to hunter.
• --auth <auth> - Defines a password to use as an authentication key, only incoming senders with the correct auth will be accepted.
• --auto-parse <regex> - Automatically parses nodes matching this regex when they are added.

Hunter also has the ability to automatically apply a profile identity to nodes as soon as they are parsed. This is called auto-apply - it is not a command line option, it must be configured through hunter config files or cloud init data passed to the node on creation.

Connecting to the hunter node can be done with the command flight hunter send. And a message will be displayed on a successful transmission. e.g.

[flight@chead1 ~]$ flight hunter send
Successful transmission

• --port <port number> - Overrides the default port to send to.
• --server <ip address> - Overrides the default server name, useful if the default is not set.
• --auth <auth> - Defines a password to use as an authentication key.
• --broadcast - Makes send broadcast to all addresses on the default subnet.
• --broadcast-address <subnet> - Overrides the default subnet to send to, use if the default subnet was not configured.
• --groups <group1,group2,group3...> - Specifies the groups that this nodes should be in.
• --label <label> - Defines a label to use when parsing this node.
• --prefix <prefix> - Defines a prefix, which will be numbered, and used as a label.
• --command <command> - Runs the given console command and sends the output as the payload of the send.

One of hunter's main features is the ability to parse discovered nodes to prepare them for use with other flight tools. This can be done with the command flight hunter parse.

The parse command will generate a list, for example:

[flight@login-node.novalocal ~]$ flight hunter parse
Select nodes: (Scroll for more nodes)
‣ ⬡ login-node.novalocal - 127.0.0.1
  ⬡ compute-node-1.novalocal - 10.151.15.194
  ⬡ compute-node-2.novalocal - 10.151.15.238

To parse, select a from the list with the space key, and you will be taken to the label editor.

Choose label: login-node.novalocal

Here, you can edit the label like plain text.

Choose label: login1

When done editing, press the enter key to save. The modified node label will appear next to the ip address and original node label.

Select nodes: login-node.novalocal - 127.0.0.1 (login1) (Scroll for more nodes)
‣ ⬢ login-node.novalocal - 127.0.0.1 (login1)
  ⬡ compute-node-1.novalocal - 10.151.15.194
  ⬡ compute-node-2.novalocal - 10.151.15.238

From this point, you can either hit the enter key to finish parsing and process the selected nodes, or continue changing node labels. Either way, you can return to this list by running flight hunter parse again.

There are some additional options that can be used with parse.

• --prefix <prefix> - Defines a prefix, which will be numbered, and used as a label.
• --start <number> - Defines the start value for the numbering of prefixes.
• --auto - Automatically parses everything in the buffer list.
• --allow-existing - Duplicate entries will replace existing ones rather than being rejected.
• --skip-used-index - If there is already a node with particular label, then entering the a different node with the same label will increase the index to the next available one instead of throwing an error.

Hunter has more commands that aren't as big as the three mentioned earlier.

This command automatically runs either hunt or send based on its configuration.

Drops all nodes in the buffer list.

Shows all nodes in the parsed list of nodes, and has several additional options:

• --plain - Displays in a plain format
• --by-group - Displays by group.
• --buffer - Shows the buffer list instead.

Allows for adding or removing of groups to a node.

• --add <groups> - Adds a group or comma separated list of groups.
• --remove <groups> - Removes a group or comma separated list of groups.
• --buffer - Modifies groups in the buffer list instead.
• --regex - The nodename is parsed as regex instead, and group changes are made to all nodes that match.

Changes the label of a node from its current one to a new one.

Remove a node from the parsed list.

• --buffer - Remove from the buffer list, and used the node id instead.
• --name - Specify the node by regex matching the hostname instead.

Renames a group, keeping all the nodes it contains.

• --buffer - Uses the buffer list instead.

Shows the details of a node, identifying it by label

• --buffer - View a node in the buffer list instead, identifying it by id.
• --plain - Print in a plain format, more easily machine readable.