Fix MTU size in ArvanCloud servers permanently

fix-mtu.sh

#!/bin/sh

# Root access?
[ "$UID" -eq 0 ] || exec sudo bash "$0" "$@"

# set tab size to 4 spaces
tabs 4

echo "Enter your network name: "
read NETPLAN_NAME

echo "Enter pereferd mtu size: "
read NETPLAN_MTU

MAC_ADDR=$(ip addr show | grep -A1 'eth0:' | awk 'FNR==2 {print $2}')

echo "Starting to configure netplan..."
echo "Your network name is $NETPLAN_NAME and mac address is $MAC_ADDR"

NETPLAN_CONFIG=$(cat <<-END
network:\n
\tversion: 2\n
\tethernets:\n
\t\t$NETPLAN_NAME:\n
\t\t\tdhcp4: true\n
\t\t\tmatch:\n
\t\t\t\tmacaddress: $MAC_ADDR\n
\t\t\tmtu: $NETPLAN_MTU\n
\t\t\tset-name: $NETPLAN_NAME
END
)

echo $NETPLAN_CONFIG > /etc/netplan/50-cloud-init.yaml
echo 'network: {config: disabled}' > /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg

# safe replace of tabs with spaces
expand --tabs=4 /etc/netplan/50-cloud-init.yaml > /etc/netplan/50-cloud-init.yaml.spaces
mv /etc/netplan/50-cloud-init.yaml /etc/netplan/50-cloud-init.yaml.tabs
mv /etc/netplan/50-cloud-init.yaml.spaces /etc/netplan/50-cloud-init.yaml


echo "MTU is configured..."
echo "Configuration is: \n"
cat -n /etc/netplan/50-cloud-init.yaml

echo "\n\nRun below commands to apply the changes..."
echo "\r\rsudo netplan apply -d"
echo "\r\rsudo systemctl restart systemd-networkd.service"
echo "\n\n"