xref: /illumos-gate/usr/src/man/man7/pxeboot.7 (revision abb88ab1b9516b1ca12094db7f2cfb5d91e0a135)
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27.Dd Apr 13, 2018
28.Dt PXEBOOT 7
29.Os
30.Sh NAME
31.Nm pxeboot
32.Nd Preboot Execution Environment (PXE) bootloader
33.Sh DESCRIPTION
34The
35.Nm
36bootloader is a modified version of the system third-stage bootstrap
37.Xr loader 7
38configured to run under Intel's Preboot Execution Environment (PXE) system.
39PXE is a form of smart boot ROM, built into Ethernet cards, and
40Ethernet-equipped motherboards.
41PXE supports DHCP configuration and provides low-level NIC access services.
42.Pp
43The DHCP client will set a DHCP user class named
44.Va illumos
45to allow flexible configuration of the DHCP server.
46.Pp
47The
48.Nm
49bootloader retrieves the kernel, modules,
50and other files either via NFS over UDP or by TFTP,
51selectable through DHCP options.
52.Pp
53The
54.Nm
55binary is loaded just like any other boot file,
56by specifying it in the DHCP server's configuration file.
57Below is a sample configuration for the ISC DHCP server:
58.Bd -literal -offset indent
59option domain-name "example.com";
60option routers 10.0.0.1;
61option subnet-mask 255.255.255.0;
62option broadcast-address 10.0.0.255;
63option domain-name-servers 10.0.0.1;
64server-name "DHCPserver";
65server-identifier 10.0.0.1;
66
67default-lease-time 120;
68max-lease-time 120;
69
70subnet 10.0.0.0 netmask 255.255.255.0 {
71       filename "pxeboot";
72       range 10.0.0.10 10.0.0.254;
73       if exists user-class and option user-class ~~ "illumos" {
74            option root-path "tftp://10.0.0.1/illumos";
75       }
76}
77
78.Ed
79.Pp
80.Nm
81recognizes
82.Va next-server
83and
84.Va option root-path
85directives as the server and path to NFS mount for file requests,
86respectively, or the server to make TFTP requests to.
87Note that
88.Nm
89expects to fetch
90.Pa /boot/loader.rc
91from the specified server before loading any other files.
92.Pp
93Valid
94.Cm option Va root-path
95syntax is
96.Bd -literal -offset indent
97[<scheme>://][<ip-address>/]<path>
98.Ed
99.Pp
100\&...where
101.Qq scheme
102is either
103.Qq nfs
104or
105.Qq tftp ,
106.Qq ip-address
107is the address of the server, and
108.Qq path
109is the path to the root filesystem on the server.
110If
111.Qq scheme
112is not specified,
113.Nm
114defaults to using NFS if the
115.Va root-path
116variable is in the
117.Qq Pa ip-address Ns :/ Ns Pa path
118form, otherwise TFTP is used.
119If no
120.Va root-path
121option is set in the DHCP response,
122.Nm
123defaults to using TFTP.
124.Pp
125.Nm
126defaults to a conservative 1024 byte NFS data packet size.
127This may be changed by setting the
128.Va nfs.read_size
129variable in
130.Pa /boot/loader.conf .
131Valid values range from 1024 to 16384 bytes.
132.Pp
133TFTP block size can be controlled by setting the
134.Va tftp.blksize
135variable in
136.Pa /boot/loader.conf .
137Valid values range from 8 to 9008 bytes.
138.Pp
139In all other respects,
140.Nm
141acts just like
142.Xr loader 7 .
143.Pp
144For further information on Intel's PXE specifications and Wired for
145Management (WfM) systems, see
146.Li http://www.intel.com/design/archives/wfm/ .
147.Sh SEE ALSO
148.Xr loader 7
149