92 lines
2.9 KiB
Bash
92 lines
2.9 KiB
Bash
# The spare interface: eth1, cabled to a small lab network,
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# 192.168.50.0/24, where a machine answers at 192.168.50.1 (and
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# fd00:50::1).
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ip link show eth1 >/dev/null 2>&1 && refuse "this VM already has an eth1; the lab adds its own spare eth1"
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command -v nmcli >/dev/null && systemctl is-active --quiet NetworkManager || refuse "this lab needs NetworkManager running"
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mkdir -p /usr/local/lib/le-lab
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cat >/usr/local/lib/le-lab/spare-net.sh <<'X'
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#!/bin/sh
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# The lab's spare network: eth1 here, the gateway 192.168.50.1 in the
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# le-net50 namespace. Run at every boot.
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ip netns list | grep -qw le-net50 || ip netns add le-net50
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ip -n le-net50 link set lo up
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ip link show eth1 >/dev/null 2>&1 || ip link add eth1 address 52:54:00:4c:45:01 type veth peer name gw netns le-net50
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ip -n le-net50 addr replace 192.168.50.1/24 dev gw
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ip -n le-net50 addr replace fd00:50::1/64 dev gw nodad
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ip -n le-net50 link set gw up
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true
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X
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chmod 755 /usr/local/lib/le-lab/spare-net.sh
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cat >/etc/systemd/system/le-lab-spare-net.service <<'X'
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[Unit]
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Description=Practice lab: a spare network interface, eth1
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Before=network-pre.target NetworkManager.service
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Wants=network-pre.target
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[Service]
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Type=oneshot
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RemainAfterExit=yes
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ExecStart=/usr/local/lib/le-lab/spare-net.sh
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[Install]
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WantedBy=multi-user.target
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X
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# NetworkManager manages eth1 but makes no profile for it on its own. A
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# gateway and DNS server on eth1 rank below the main interface's, so the
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# VM keeps its own way out.
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cat >/etc/NetworkManager/conf.d/91-le-lab-spare.conf <<'X'
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[main]
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no-auto-default+=interface-name:eth1
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[device-le-lab-spare]
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match-device=interface-name:eth1
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managed=1
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[connection-le-lab-spare]
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match-device=interface-name:eth1
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ipv4.route-metric=500
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ipv6.route-metric=500
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ipv4.dns-priority=200
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ipv6.dns-priority=200
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X
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systemctl reload NetworkManager
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systemctl daemon-reload
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systemctl enable --now --quiet le-lab-spare-net.service
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for i in 1 2 3 4 5 6 7 8 9 10; do
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nmcli -g GENERAL.STATE device show eth1 2>/dev/null | grep -qv unmanaged && break
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sleep 1
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done
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# Note the profiles for eth1 and their IPv4 addresses (task 2 and 3).
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cat >/usr/local/lib/le-lab/watch.sh <<'X'
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#!/bin/bash
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# Notes each change of what snap prints.
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log=$1 prev=''
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snap() {
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local u
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for u in $(nmcli -g UUID connection show 2>/dev/null); do
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[ "$(nmcli -g connection.interface-name connection show "$u" 2>/dev/null)" = eth1 ] || continue
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printf '%s=%s ' "$u" "$(nmcli -g ipv4.addresses connection show "$u" 2>/dev/null | tr -d ' ')"
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done
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}
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while :; do
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cur=$(snap)
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[ "$cur" = "$prev" ] || { printf '%s\n' "$cur" >>"$log"; prev=$cur; }
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sleep 2
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done
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X
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cat >/etc/systemd/system/le-lab-watch.service <<X
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[Unit]
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Description=LINUXexpert practice lab: note the profiles for eth1
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After=NetworkManager.service
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[Service]
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ExecStart=/bin/bash /usr/local/lib/le-lab/watch.sh $LAB_STATE/watch.log
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Restart=always
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[Install]
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WantedBy=multi-user.target
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X
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systemctl daemon-reload
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systemctl enable --now --quiet le-lab-watch.service
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