Setup a network namespace with Internet access

ns-inet-mysql.sh

#!/usr/bin/env bash

set -x

NS="mysql"
VETH="vethmysql"
VPEER="vpeermysql"
VETH_ADDR="10.200.1.1"
VPEER_ADDR="10.200.1.2"

if [[ $EUID -ne 0 ]]; then
    echo "You must be root to run this script"
    exit 1
fi

# Remove namespace if it exists.
ip netns del $NS &>/dev/null

# Create namespace
ip netns add $NS

# Create veth link.
ip link add ${VETH} type veth peer name ${VPEER}

# Add peer-1 to NS.
ip link set ${VPEER} netns $NS

# Setup IP address of ${VETH}.
ip addr add ${VETH_ADDR}/24 dev ${VETH}
ip link set ${VETH} up

# Setup IP ${VPEER}.
ip netns exec $NS ip addr add ${VPEER_ADDR}/24 dev ${VPEER}
ip netns exec $NS ip link set ${VPEER} up
ip netns exec $NS ip link set lo up
ip netns exec $NS ip route add default via ${VETH_ADDR}

# Enable IP-forwarding.
echo 1 > /proc/sys/net/ipv4/ip_forward

ns-inet-wp.sh

#!/usr/bin/env bash

set -x

NS="wp"
VETH="vethwp"
VPEER="vpeerwp"
VETH_ADDR="10.200.2.1"
VPEER_ADDR="10.200.2.2"

if [[ $EUID -ne 0 ]]; then
    echo "You must be root to run this script"
    exit 1
fi

# Remove namespace if it exists.
ip netns del $NS &>/dev/null

# Create namespace
ip netns add $NS

# Create veth link.
ip link add ${VETH} type veth peer name ${VPEER}

# Add peer-1 to NS.
ip link set ${VPEER} netns $NS

# Setup IP address of ${VETH}.
ip addr add ${VETH_ADDR}/24 dev ${VETH}
ip link set ${VETH} up

# Setup IP ${VPEER}.
ip netns exec $NS ip addr add ${VPEER_ADDR}/24 dev ${VPEER}
ip netns exec $NS ip link set ${VPEER} up
ip netns exec $NS ip link set lo up
ip netns exec $NS ip route add default via ${VETH_ADDR}

# Enable IP-forwarding.
echo 1 > /proc/sys/net/ipv4/ip_forward