IPv6 network boot with iPXE
IPv6地址获取方式
IPv6地址获取主要分为以下几种
IPv6地址获取方式
| N/A | 预设闸道 | 地址分配 | DNS |
|---|---|---|---|
| 手动配置 | 手动 | 手动 | 手动 |
| SLAAC RDNSS | RA | RA | RA |
| SLAAC DHCPv6 | RA | RA | DHCP |
| Stateful DHCPv6 | RA | DHCP | DHCP |
RA: Router Advertisement
SLAAC: Stateless Address Autoconfiguration
RDNSS: Recursive DNS Server
自动获取IPv6地址时获取信息的方式主要通过RA的M位与O位控制.
- M (Managed Address Configuration)
- O (Other Configuration)
M = 1 表示 Client需要去DHCPv6获取 IPv6 Prefix
O =1 表示 Client需要去DHCPv6获取DNS等信息
1. SLAAC + RDNSS M = 0, O = 0 Client将从RA获得prefix, DNS等信息. RA一般由Router提供, 在Linux环境下可以通过radvd服务提供
2. SLAAC + DHCPv6 M = 0, O = 1 Client将从RA获取prefix, 其他信息比如DNS由DHCPv6提供
3. Stateful DHCPv6 M = 1, O = 1 Client将从DHCPv6获取所有信息IPv6地址获取流程
Client 使用 UDP 546 端口, Server 使用 UDP 547 端口, 但IPv6不使用 broadcast方式获取地址.
假设
Client的 link-local address 是 fe80::6e92:bfff:fe07
Server的 link-local address 是 fe80::21b:21ff:fe36
IPv6 multicast addresses ff01::1:2
- DHCPv6 client sends a Solicit from [fe80::6e92:bfff:fe07] for [ff01::1]
- DHCPv6 server replies with an Advertise from [fe80::21b:21ff:fe36] for [fe80::6e92:bfff:fe07]
- DHCPv6 client replies with a Request from [fe80::6e92:bfff:fe07] for [ff01::1]
- DHCPv6 server finishes with an Reply from [fe80::21b:21ff:fe36] for [fe80::6e92:bfff:fe07]
RADVD
Managed will tell the target host to request its IPv6 address from a DHCPv6 server instead of using SLAAC.
Other is important bit, as it tells the target host that (non-address related) configuration information is available from the DHCPv6 server.
/etc/radvd.conf
interface eth0
{
AdvSendAdvert on;
MinRtrAdvInterval 30;
MaxRtrAdvInterval 100;
AdvManagedFlag on;
AdvOtherConfigFlag on;
prefix 3ffe:501:ffff:100::/64
{
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr off;
};
};启用radvd时必须启用 IPv6 forwarding功能
echo "net.ipv6.conf.all.forwarding = 1" >> /etc/sysctl.conf | sysctl -pDHCPv6 (isc-dhcp-server)
/etc/dhcp/dhcpd6.conf
default-lease-time 2592000;
preferred-lifetime 604800;
option dhcp-renewal-time 3600;
option dhcp-rebinding-time 7200;
allow leasequery;
option dhcp6.preference 255;
option dhcp6.info-refresh-time 21600;
dhcpv6-lease-file-name "/var/lib/dhcpd/dhcpd6.leases";
option dhcp6.name-servers 2001:4860:4860::8888; # Use Google's Public DNS Server
option dhcp6.domain-search "test.example.com","example.com";
option dhcp6.user-class code 15 = string;
option dhcp6.vendor-class-data code 16 = string;
option dhcp6.bootfile-url code 59 = string;
option dhcp6.client-arch-type code 61 = array of unsigned integer 16;
if exists dhcp6.user-class and
substring(option dhcp6.user-class, 2, 4) = "iPXE" {
option dhcp6.bootfile-url "http://[3ffe:501:ffff:100::1]/start.ipxe";
} else {
if option dhcp6.client-arch-type = 00:00 {
option dhcp6.bootfile-url "tftp://[3ffe:501:ffff:100::1]/undionly.kpxe"; # Standard PC BIOS
} elsif option dhcp6.client-arch-type = 00:06 {
option dhcp6.bootfile-url "tftp://[3ffe:501:ffff:100::1]/ipxe.efi"; # 32-bit x86 EFI
} elsif option dhcp6.client-arch-type = 00:07 {
option dhcp6.bootfile-url "tftp://[3ffe:501:ffff:100::1]/ipxe.efi"; # 64-bit x86 EFI
} elsif option dhcp6.client-arch-type = 00:09 {
option dhcp6.bootfile-url "tftp://[3ffe:501:ffff:100::1]/ipxe.efi"; # 64-bit x86 EFI(obsolete)
} elsif option dhcp6.client-arch-type = 00:0a {
option dhcp6.bootfile-url "tftp://[3ffe:501:ffff:100::1]/ipxe.efi"; # 32-bit ARM EFI
} elsif option dhcp6.client-arch-type = 00:0b {
option dhcp6.bootfile-url "tftp://[3ffe:501:ffff:100::1]/arm64.efi"; # 64-bit ARM EFI
}
}
subnet6 3ffe:501:ffff:100::/64 {
range6 3ffe:501:ffff:100::10 3ffe:501:ffff:100::50;
range6 3ffe:501:ffff:100:: temporary;
prefix6 3ffe:501:ffff:100:: 3ffe:501:ffff:111:: /64;
}tftp server
/etc/xinetd.d/tftp
flags默认是IPv4 仅支持IPv4; 修改为IPv6后同时支持IPv6和IPv4
service tftp
{
socket_type = dgram
protocol = udp
wait = yes
user = root
server = /usr/sbin/in.tftpd
server_args = -s /var/lib/tftpboot
disable = no
per_source = 11
cps = 100 2
flags = IPv6
}http server
Just deploy a simple http server to serve http request.
iPXE
start.ipxe
#!ipxe
set conn_type http
chain --autofree http://[3ffe:501:ffff:100::1]/menu.ipxe || echo HTTP failed, localbooting...menu.ipxe
#!ipxe
show ip6
set menu-timeout 5000
set submenu-timeout ${menu-timeout}
# Ensure we have menu-default set to something
isset ${menu-default} || set menu-default localhdd
set boot-url http://[3ffe:501:ffff:100::1]
set keep-san 1
######## MAIN MENU #############
:start
menu iPXE Boot Menu
item
item --gap -- -------Advanced configuration -----------
item --key 0 localhdd [0] Local HDD
item --key 2 linux [2] Linux Install
item --gap -- ---------------------------
choose --default ${menu-default} --timeout 30000 target && goto ${target}
##### Main Items ########
:localhdd
exit
:linux
menu Linux Menu
item redhat74 RedHat74
choose target && goto ${target}
:redhat74
echo Install Red Hat 7.4
set centos_url ${boot-url}/linux/redhat/7.4
iseq ${platform} efi && goto centos_efi || goto centos_legacy
:centos_efi
echo Starting Install RedHat (UEFI)
kernel ${centos_url}/images/pxeboot/vmlinuz initrd=initrd.img inst.loglevel=debug repo=${centos_url} noipv4 ip=dhcp6
initrd ${centos_url}/images/pxeboot/initrd.img
boot
:centos_legacy
echo Starting Install CentOS (Legacy BIOS)
kernel ${centos_url}/images/pxeboot/vmlinuz initrd=initrd.img repo=${centos_url}
initrd ${centos_url}/images/pxeboot/initrd.img
bootDHCPv6 Options
The list of assigned values used in DHCPv6 is available at:
https://www.iana.org/assignments/dhcpv6-parameters/dhcpv6-parameters.xhtml
References