Setup

Networking

Following is the information on the networking setup in the Raspberry-Pis.

Worker nodes

In order to statically define the IP addresses in the network, the following snippet is appended to /etc/dhcpcd.conf file of the worker nodes.

# To be appended to /etc/dhcpcd.conf

interface eth0
static ip_address=172.22.69.1*/24   # Change IP according to the node
static routers=172.22.69.1
static domain_name_server=8.8.8.8

Attention

Replace the asterisk in the previous code block with the node number.

Master node

Similar to what was done in the previous sub-section, we append the next code snippet to /etc/dhcpcd.conf of the master node. It allows the cluster to recognize the universty network and vice-versa. It also allows the worker nodes to recognize the fact that the master node is on VLAN 10 (lines 3 and 8).

# To be appended to /etc/dhcpcd.conf

interface eth0
static ip_address=10.59.114.70/23 # IP address of the university network
static routers=10.59.114.1 # IP address of the university router
static domain_name_server=8.8.8.8

interface eth0.10
static ip_address=172.22.69.1/24 # IP address of the master node
static routers=172.22.69.1
static domain_name_servers=8.8.8.8

Caution

Do not use the transparency here with malicious intent.

The following must be appended to /etc/network/interfaces.d/vlans. It creates the virtual interfaces which are then recognized by the network.

# To be appended to /etc/network/interfaces.d/vlans

auto eth0.10
iface eth0.10 inet manual
    vlan-raw-device eth0

The following bash script is to setup IP forwarding on the master node.

#! /bin/bash

IPTABLES=/sbin/iptables

WANIF='eth0'
LANIF='eth0.10'

# enable ip forwarding in the kernel
#echo 'Enabling Kernel IP forwarding...'
#/bin/echo 1 > /proc/sys/net/ipv4/ip_forward

# flush rules and delete chains
echo 'Flushing rules and deleting existing chains...'
$IPTABLES -F
$IPTABLES -X

# enable masquerading to allow LAN internet access
echo 'Enabling IP Masquerading and other rules...'
$IPTABLES -t nat -A POSTROUTING -o $LANIF -j MASQUERADE
$IPTABLES -A FORWARD -i $LANIF -o $WANIF -m state --state RELATED,ESTABLISHED -j ACCEPT
$IPTABLES -A FORWARD -i $WANIF -o $LANIF -j ACCEPT

$IPTABLES -t nat -A POSTROUTING -o $WANIF -j MASQUERADE
$IPTABLES -A FORWARD -i $WANIF -o $LANIF -m state --state RELATED,ESTABLISHED -j ACCEPT
$IPTABLES -A FORWARD -i $LANIF -o $WANIF -j ACCEPT

# Make sure to install the package 'iptables-persistent' to make the routing persistent across reboots