kafs-client.conf man page

/etc/kafs/client.conf
/etc/kafs/client.d/ — kAFS filesystem configuration

Description

Configuration information for the in-kernel kAFS filesystem can be provided in the /etc/kafs/ directory.  This may include the following:

- A list of cells to be preconfigured

- Fallback addresses for each cell.

- The name of the default cell (the @cell substitution).

- A list of strings for the @sys substitution.

When the afs.mount service is started by systemd(1), a configuration service (kafs-config.service) runs first and loads the configuration into the kernel from the client.conf file.  This contains directives to include other things, such as the contents of the client.d/ directory and the generic public cell database.

Once the afs.mount service is started (or if an AFS volume is manually mounted), if a mountpoint is triggered, the kernel will upcall by means of request-key(8) to look up addresses for the Volume Location servers for the named cell.  This will also parse the configuration.

Configuration File Format

The file format is based on the MIT Kerberos configuration file format.  There are a couple of general directives:

include /path/to/file

This includes the contents of the named file in the parse at this point.

includedir /path/to/dir/

This includes the files in the named directory in the parse at this point. Files that have names beginning with "." or ending with "~" are ignored.

Leading and trailing whitespace on a line is ignored.  Any line otherwise beginning with a "#" character is considered a comment and ignored.

Any line that contains a label bounded by square brackets, e.g. "[cells]", by itself on that line denotes a switch to the section specified by that label.

Configuration data is specified within a named section as a series of key=value pairs, where a value may be one of nothing, an unquoted string, a quoted string or a braced lists containing further key=value pairs.  Whitespace either side of the "=" symbol is ignored.

For example:

[cells]
rivendell.example.com = {
	description = "Last Homely Cell"
	use_dns = yes
	servers = {
		elrond.rivendell.example.com = {
			address = 192.0.2.23
		}
	}
}

If two or more consecutive clauses specify values for the same key sequence (so cells:rivendell.example.com:use_dns, for example), then they are merged together to form a single list.  If a single value is expected for a configuration item, the last element in the list is taken.

To prevent overriding by subsequent conflicting configuration, an asterisk can be placed after the closing brace in a braced list to indicate that that list is closed, for example:

[cells]
rivendell.example.com = {
	description = "Foo"
	use_dns = no
}*

Strings that are intepreted as boolean values are classed as false if they match one of 0, f, false, n, no or off, and classed as true if they match one off 1, t, true, y, yes or on. The match is case-independent.

General Settings

The first section contains general system-level settings shared between all utilities and the kernel.  This is denoted by the section label "[defaults]".

The system settings that may be changed are configured in this section with the following key-value pairs:

thiscell = <cellname>

This sets the name of the local cell.  This will be used to configure the @cell path substitution and will also supply the default cellname for aklog-kafs(1).

sysname = [<systype>]*

This specifies a (potentially empty) list of strings which the kernel should attempt to substitute in turn for "@sys" at the end of a filename until a match is found.

Cell Definitions

The second section contains a list of preconfigured cells, to be used in preloading the cell list in /afs and also to provide fallback or override address data for locating Volume Location servers.  This is denoted by the section label "[cells]".

Within the cell list, each cell is declared with a key=value pair, where the key is the name of the cell and the value is a braced list indicating the details, e.g.:

[cells]
rivendell.example.com = {
	...
}

A cell definition may contain any number of key=value pairs.  The keys that are taken note of are:

description = <string>

This is a text description for the cell.

show_cell = <boolean>

Whether a cell should be shown in /afs.

use_dns = <boolean>

Whether address look ups for a cell may use the DNS.

kerberos_realm = <string>

The name of the Kerberos realm to use for a cell by default.

servers = { ... }

A list of servers for the cell, where each element in the list is a key=value pair, where the key is the name of a server and the value is a braced section of the details for that server.

The elements in the list of server details attached to each server can comprise the following keys:

type = vlserver

The server is an AFS Volume Location server.  This is the default.

type = ptserver

The server is an AFS Protection server.

address = [<protocol>/]<address>[:<port>]

Specify a single address for a server.  The address is required and can be a single IPv4 or a single IPv6 address, and may be brackets with square brackets (to avoid confusion with the port number, if specified).  The protocol is optional; currently only udp is supported.  The port is also optional and may be specified to change the UDP port from the default for the server type.

Example

[defaults]
thiscell = rivendell.example.com
sysname = fedora28_x86 amd64_linux

[cells]
corp.example.com = {
	description = "Valinor Corporation cell"
	use_dns = yes
	servers = {
		manwe.corp.example.com = {
			address = 2001:db8:123::13
			address = 203.0.113.19
		}
		ulmo.corp.example.com = {
			address = [2001:db8:123::750c:1234]:6666
			address = 203.0.113.3:6666
		}
		aule.corp.example.com = {
			address = udp/[2001:db8:123::abcd:9090]
			address = udp/203.0.113.189
		}
		namo.corp.example.com = {
			type = ptserver
			address = 2001:db8:123::8888
			address = 203.0.113.88
		}
	}
}

rivendell.example.com = {
	description = "Last Homely Cell"
	servers = {
		elrond.rivendell.example.com = {
			address = 192.0.2.23
		}
		arwen.rivendell.example.com = {
			address = 192.0.2.75
		}
	}
}

See Also

kafs(7), kafs-check-config(8), systemd(1)

Referenced By

kafs(7), kafs-check-config(8).

17 Apr 2019 Linux kAFS Configuration