Elastic Compute Service:Konfigurasikan custom image Linux

Langkah 1: Buat direktori konfigurasi

Login ke mesin virtual sebagai pengguna root. Buat direktori aliyun_custom_image di root partisi pertama:

mkdir /aliyun_custom_image

Saat instans pertama kali boot, ECS menulis konfigurasi ke file os.conf di direktori ini. Jika file tersebut belum ada, ECS akan membuatnya. File ini memiliki format berikut:

hostname=<yourHostName>
password=<yourPassword>
eth0_ip_addr=10.0.0.2
eth0_mac_addr=00:xx:xx:xx:xx:23
eth0_netmask=255.255.255.0
eth0_gateway=10.0.0.1
eth0_route="0.0.0.0/0 10.0.0.1"
dns_nameserver="7.7.X.X 8.8.8.8"

Tabel berikut menjelaskan setiap parameter.

Langkah 2: Tambahkan skrip inisialisasi

Buat skrip inisialisasi dalam image untuk membaca file os.conf dan menerapkan konfigurasi. Beri nama file skrip tersebut, misalnya, customized-config.service.

Skrip contoh berikut mengatur hostname, password root, server DNS, dan konfigurasi jaringan saat boot pertama. Skrip ini menggunakan framework layanan sysvinit.

#!/bin/bash

### BEGIN INIT INFO
# Provides:          os-conf
# Required-Start:    $local_fs $network $named $remote_fs
# Required-Stop:
# Should-Stop:
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
# Short-Description: Initialize system configuration
### END INIT INFO

# Define the directory for the first partition and os.conf file
first_partition_dir='/boot/'
os_conf_dir=${first_partition_dir}/aliyun_custom_image
os_conf_file=${os_conf_dir}/os.conf

# Load os.conf if it exists
load_os_conf() {
    if [[ -f $os_conf_file ]]; then
        . $os_conf_file
        return 0
    else
        return 1
    fi
}

# Cleanup function to remove os.conf and ensure directory exists
cleanup() {
    rm $os_conf_file >& /dev/null
    mkdir -p $os_conf_dir
}

# Configure the root password
config_password() {
    if [[ -n $password ]]; then
        password=$(echo $password | base64 -d)
        if [[ $? == 0 && -n $password ]]; then
            echo "root:$password" | chpasswd
        fi
    fi
}

# Set the hostname
config_hostname() {
    if [[ -n $hostname ]]; then
        sed -i "s/^HOSTNAME=.*/HOSTNAME=$hostname/" /etc/sysconfig/network
        hostname $hostname
    fi
}

# Configure DNS settings
config_dns() {
    if [[ -n $dns_nameserver ]]; then
        dns_conf=/etc/resolv.conf
        sed -i '/^nameserver.*/d' $dns_conf
        for i in $dns_nameserver; do
            echo "nameserver $i" >> $dns_conf
        done
    fi
}

# Determine if the network is classic or VPC
is_classic_network() {
    grep -q 'eth1' $os_conf_file
}

# Configure network settings
config_network() {
    /etc/init.d/network stop
    config_interface eth0 ${eth0_ip_addr} ${eth0_netmask} ${eth0_mac_addr}
    config_route eth0 "${eth0_route}"
    if is_classic_network ; then
        config_interface eth1 ${eth1_ip_addr} ${eth1_netmask} ${eth1_mac_addr}
        config_route eth1 "${eth1_route}"
    fi
    /etc/init.d/network start
}

# Configure network interface
config_interface() {
    local interface=$1
    local ip=$2
    local netmask=$3
    local mac=$4
    interface_cfg="/etc/sysconfig/network-scripts/ifcfg-${interface}"
    cat << EOF > $interface_cfg
DEVICE=$interface
IPADDR=$ip
NETMASK=$netmask
HWADDR=$mac
ONBOOT=yes
BOOTPROTO=static
EOF
}

# Set the default gateway
config_default_gateway() {
    local gateway=$1
    sed -i "s/^GATEWAY=.*/GATEWAY=$gateway/" /etc/sysconfig/network
}

# Configure routing
config_route() {
    local interface=$1
    local route="$2"
    route_conf=/etc/sysconfig/network-scripts/route-${interface}
    > $route_conf
    echo $route | sed 's/;/\n/' | \
        while read line; do
            dst=$(echo $line | awk '{print $1}')
            gw=$(echo $line | awk '{print $2}')
            if ! grep -q "$dst" $route_conf 2> /dev/null; then
                echo "$dst via $gw dev $interface" >> $route_conf
            fi
            if [[ "$dst" == "0.0.0.0/0" ]]; then
                config_default_gateway $gw
            fi
        done
}

################## sysvinit service portal ####################

# Start the configuration process
start() {
    if load_os_conf ; then
        config_password
        config_network
        config_hostname
        config_dns
        cleanup
        return 0
    else
        echo "not load $os_conf_file"
        return 0
    fi
}

RETVAL=0

# Service action handling
case "$1" in
    start)
        start
        RETVAL=$?
    ;;
    *)
        echo "Usage: $0 {start}"
        RETVAL=3
    ;;
esac

exit $RETVAL

Langkah 3: Aktifkan skrip saat startup

Konfigurasikan skrip inisialisasi agar berjalan otomatis saat sistem startup. Perintah berikut berlaku untuk sistem berbasis Ubuntu dan systemd — sesuaikan dengan sistem init distribusi Anda jika diperlukan.

systemctl daemon-reload
systemctl enable customized-config.service

Saat Anda membuat custom image berdasarkan image Customized Linux, skrip startup disertakan dalam image baru tersebut. ECS hanya menjalankan konfigurasi os.conf pada boot pertama setiap instans.