DHCP-Abschnitt eingefügt

This commit is contained in:
Alfred Krohmer 2013-11-21 10:38:15 +01:00
parent d1d5cfe315
commit 0b99d005ef
8 changed files with 334 additions and 4 deletions

155
aufgabe3.2/30-hostname Normal file
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# Set the hostname from DHCP data if required
# A hostname can either be a short hostname or a FQDN.
# hostname_fqdn=true
hostname_fqdn=false
# hostname_fqdn=server
# A value of server means just what the server says, don't manipulate it.
# This could lead to an inconsistent hostname on a DHCPv4 and DHCPv6 network
# where the DHCPv4 hostname is short and the DHCPv6 has an FQDN.
# DHCPv6 has no hostname option.
# RFC4702 section 3.1 says FQDN should be prefered over hostname.
#
# As such, the default is hostname_fqdn=true so that a consistent hostname
# is always assigned.
: ${hostname_fqdn:=true}
# Some systems don't have hostname(1)
_hostname()
{
local name=
if [ -z "$1" ]; then
if type hostname >/dev/null 2>&1; then
hostname
elif [ -r /proc/sys/kernel/hostname ]; then
read name </proc/sys/kernel/hostname && echo "$name"
elif sysctl kern.hostname >/dev/null 2>&1; then
sysctl -n kern.hostname
elif sysctl kernel.hostname >/dev/null 2>&1; then
sysctl -n kernel.hostname
else
return 1
fi
return $?
fi
# Always prefer hostname(1) if we have it
if type hostname >/dev/null 2>&1; then
#hostname "$1"
hostnamectl set-hostname "$1"
elif [ -w /proc/sys/kernel/hostname ]; then
echo "$1" >/proc/sys/kernel/hostname
elif sysctl kern.hostname >/dev/null 2>&1; then
sysctl -w "kern.hostname=$1"
elif sysctl kernel.hostname >/dev/null 2>&1; then
sysctl -w "kernel.hostname=$1"
else
# We know this will fail, but it will now fail
# with an error to stdout
hostname "$1"
fi
}
need_hostname()
{
local hostname hfqdn=false hshort=false
case "$force_hostname" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) return 0;;
esac
hostname="$(_hostname)"
case "$hostname" in
""|"(none)"|localhost|localhost.localdomain) return 0;;
esac
case "$hostname_fqdn" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) hfqdn=true;;
[Ss][Ee][Rr][Vv][Ee][Rr]) ;;
*) hshort=true;;
esac
if [ -n "$old_fqdn" ]; then
if ${hfqdn} || ! ${hsort}; then
[ "$hostname" = "$old_fqdn" ]
else
[ "$hostname" = "${old_fqdn%%.*}" ]
fi
elif [ -n "$old_host_name" ]; then
if ${hfqdn}; then
if [ -n "$old_domain_name" -a \
"$old_host_name" = "${old_host_name#*.}" ]
then
[ "$hostname" = \
"$old_host_name.$old_domain_name" ]
else
[ "$hostname" = "$old_host_name" ]
fi
elif ${hshort}; then
[ "$hostname" = "${old_host_name%%.*}" ]
else
[ "$hostname" = "$old_host_name" ]
fi
else
# No old hostname
false
fi
}
try_hostname()
{
if valid_domainname "$1"; then
_hostname "$1"
else
syslog err "Invalid hostname: $1"
fi
}
set_hostname()
{
local hfqdn=false hshort=false
need_hostname || return
case "$hostname_fqdn" in
[Yy][Ee][Ss]|[Tt][Rr][Uu][Ee]|1) hfqdn=true;;
"") ;;
*) hshort=true;;
esac
if [ -n "$new_fqdn" ]; then
if ${hfqdn} || ! ${hshort}; then
try_hostname "$new_fqdn"
else
try_hostname "${new_fqdn%%.*}"
fi
elif [ -n "$new_host_name" ]; then
if ${hfqdn}; then
if [ -n "$new_domain_name" -a \
"$new_host_name" = "${new_host_name#*.}" ]
then
try_hostname "$new_host_name.$new_domain_name"
else
try_hostname "$new_host_name"
fi
elif ${hshort}; then
try_hostname "${new_host_name%%.*}"
else
try_hostname "$new_host_name"
fi
fi
}
# For ease of use, map DHCP6 names onto our DHCP4 names
case "$reason" in
BOUND6|RENEW6|REBIND6|REBOOT6|INFORM6)
new_fqdn="$new_dhcp6_fqdn"
;;
esac
if $if_up; then
set_hostname
fi

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aufgabe3.2/dhcpd.conf Normal file
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# dhcpd.conf
#
# Sample configuration file for ISC dhcpd
#
# option definitions common to all supported networks...
option domain-name "zotac";
option domain-name-servers zotac0.zotac;
default-lease-time 600;
max-lease-time 7200;
# Use this to enble / disable dynamic dns updates globally.
#ddns-update-style none;
# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;
# Use this to send dhcp log messages to a different log file (you also
# have to hack syslog.conf to complete the redirection).
log-facility local7;
# No service will be given on this subnet, but declaring it helps the
# DHCP server to understand the network topology.
subnet 10.20.0.0 netmask 255.255.255.0 {
# range 10.20.0.100 10.20.0.200;
option routers zotac0.zotac;
}
# This is a very basic subnet declaration.
#subnet 10.254.239.0 netmask 255.255.255.224 {
# range 10.254.239.10 10.254.239.20;
# option routers rtr-239-0-1.example.org, rtr-239-0-2.example.org;
#}
# This declaration allows BOOTP clients to get dynamic addresses,
# which we don't really recommend.
#subnet 10.254.239.32 netmask 255.255.255.224 {
# range dynamic-bootp 10.254.239.40 10.254.239.60;
# option broadcast-address 10.254.239.31;
# option routers rtr-239-32-1.example.org;
#}
# A slightly different configuration for an internal subnet.
#subnet 10.5.5.0 netmask 255.255.255.224 {
# range 10.5.5.26 10.5.5.30;
# option domain-name-servers ns1.internal.example.org;
# option domain-name "internal.example.org";
# option routers 10.5.5.1;
# option broadcast-address 10.5.5.31;
# default-lease-time 600;
# max-lease-time 7200;
#}
# Hosts which require special configuration options can be listed in
# host statements. If no address is specified, the address will be
# allocated dynamically (if possible), but the host-specific information
# will still come from the host declaration.
host zotac1 {
hardware ethernet 00:1c:c0:d5:a9:ee;
fixed-address zotac1.zotac;
use-host-decl-names true;
}
#host passacaglia {
# hardware ethernet 0:0:c0:5d:bd:95;
# filename "vmunix.passacaglia";
# server-name "toccata.fugue.com";
#}
# Fixed IP addresses can also be specified for hosts. These addresses
# should not also be listed as being available for dynamic assignment.
# Hosts for which fixed IP addresses have been specified can boot using
# BOOTP or DHCP. Hosts for which no fixed address is specified can only
# be booted with DHCP, unless there is an address range on the subnet
# to which a BOOTP client is connected which has the dynamic-bootp flag
# set.
#host fantasia {
# hardware ethernet 08:00:07:26:c0:a5;
# fixed-address fantasia.fugue.com;
#}
# You can declare a class of clients and then do address allocation
# based on that. The example below shows a case where all clients
# in a certain class get addresses on the 10.17.224/24 subnet, and all
# other clients get addresses on the 10.0.29/24 subnet.
#class "foo" {
# match if substring (option vendor-class-identifier, 0, 4) = "SUNW";
#}
#
#shared-network 224-29 {
# subnet 10.17.224.0 netmask 255.255.255.0 {
# option routers rtr-224.example.org;
# }
# subnet 10.0.29.0 netmask 255.255.255.0 {
# option routers rtr-29.example.org;
# }
# pool {
# allow members of "foo";
# range 10.17.224.10 10.17.224.250;
# }
# pool {
# deny members of "foo";
# range 10.0.29.10 10.0.29.230;
# }
#}

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[Unit]
Description=IPv4 DHCP server
After=network.target
[Service]
Type=forking
PIDFile=/run/dhcpd4.pid
ExecStart=/usr/sbin/dhcpd -4 -q -pf /run/dhcpd4.pid %I
KillSignal=SIGINT
[Install]
WantedBy=multi-user.target

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@ -94,3 +94,4 @@ Nach dem Burnin sollte der Compute-Node automatisch heruntergefahren werden. Daz
\shellcmd{shutdown -P 2880}
\pagebreak

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\subsubsection{DNS}
\subsection{DHCP}
\subsubsection{Server}
\begin{sloppypar}
Wir haben uns für {\tt dhcpd} als DHCP-Server entschieden. Zur Konfiguration haben wir in {\tt /etc/dhcpd.conf} (siehe {\tt aufgabe3.2}) den Domain-Namen {\tt zotac} eintragen und den Headnode als DNS-Server eingestellt.
\end{sloppypar}
Des Weiteren haben wir das Subnet {\tt 10.20.0.0/24} deklariert und wiederum den Headnode als verantwortlichen Router eingetragen.
Die Pro-Host-Konfiguration sieht bei uns wie folgt aus:
\begin{lstlisting}
host zotac<X> {
hardware ethernet <MAC-Adresse>;
fixed-address zotac<X>.zotac;
use-host-decl-names true;
}
\end{lstlisting}
Damit ist sichergestellt, dass die Hosts die im Cluster-Layout spezifizierte IP-Adresse entsprechend ihrer MAC-Adresse zugewiesen bekommen und gleichzeitig ihren Hostnamen gesagt bekommen. (Die IP-Adresse holt sich der DHCP-Server vom lokalen DNS-Server.)
Zusätzlich haben wir das bereits in der Installation enthaltene {\tt systemd}-Service-File entsprechend so angepasst, dass man beim Starten und Aktivieren des Dienstes spezifizieren kann, auf welchem Netzwerk-Interface der Dienst hören soll. (siehe {\tt aufgabe3.2/dhcpd4@.service})
Starten kann man den Dienst nun mit:
\shellcmd{systemctl start dhcpd4@eth1}
wobei {\tt eth1} das Interface ist, das am internen LAN angeschlossen ist.
\subsubsection{Client}
\begin{sloppypar}
Als Client verwenden wir {\tt dhcpcd}. \\
Um den Hostnamen richtig vom DHCP-Server abholen zu können, mussten wir in {\tt /usr/lib/dhcpcd/dhcpcd-hooks/30-hostname} (siehe {\tt aufgabe3.2/30-hostname}) noch die Option {\tt hostname\_fqdn=false} setzen, damit der kurze Hostname ({\tt zotac<X>} statt {\tt zotac<X>.zotac}) verwendet wird. \\
Außerdem haben wir noch die Zeile:
\begin{center}
{\tt hostname \grqq{\$}1\grqq}
\end{center}
durch:
\begin{center}
{\tt hostnamectl set-hostname \grqq{\$}1\grqq}
\end{center}
ersetzt, damit der bezogene Hostname automatisch persistent ({\tt /etc/hostname}) gesetzt wird.
\end{sloppypar}
\subsection{DNS}
\label{ssub:dns}
Als DNS-Server haben wir {\tt Bind} installiert und eingerichtet.

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Subproject commit 7abd329ac66148a9b6adcf5c022e84893b72a36b
Subproject commit b63daf5cbc2272cd20277a157bf025c695a5bb45

2
logs

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Subproject commit e67584ad2c8222932e65a5d340e3469780acc3b4
Subproject commit 4577c74a7b11d23834a2fd53d0f0646e0d6d0622

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@ -113,7 +113,7 @@ pre {
<section id="bericht">
<h2>Bericht</h2>
<a href="uploads/bericht.pdf" class="pure-button
pure-button-primary">Download</a> <p>Stand: 13:38:39 07.11.2013</p>
pure-button-primary">Download</a> <p>Stand: 10:38:02 21.11.2013</p>
</section>
<section id="git">
<h2>Git-Zugriff</h2>