Forced Import Image

Overview

When the user's Linux image cannot install cloudinit for some reason, you can use the Forced Import Image feature to import the image. If the user uses the forced import image for import, Converge Cloud will not be able to initialize the configuration of the user's CVM. You need to set a script to configure the CVM according to the configuration file provided by Converge Cloud. This document guides users on how to configure the CVM under the premise of forced import image.

Limitation Factor

• The image still needs to meet the imported image limits in Import Image for Linux images (except cloudinit).
• The system partition where the image is imported is not full.
• The imported image must not have vulnerabilities that can be exploited remotely.
• It is recommended that users change the password immediately after the instance is created successfully by forced import image.

Directions

The forced import image does not use cloudinit and therefore cannot be automatically configured. Converge Cloud provides a cdrom device containing configuration information for users to configure themselves. Users need to mount cdrom and read mount_point/qcloud_action/os.conf information to configure. If the user needs to use other configuration data or UserData, they can directly read the files under mount_point/.

os.conf Configuration File Content

The basic contents of os.conf are as follows:

hostname=VM_10_20_xxxx
password=GRSgae1fw9frsG.rfrF
eth0_ip_addr=10.104.62.201
eth0_mac_addr=52:54:00:E1:96:EB
eth0_netmask=255.255.192.0
eth0_gateway=10.104.0.1
dns_nameserver="10.138.224.65 10.182.20.26 10.182.24.12"

The meaning of each parameter in os.conf is as follows:

Configure Script Resolution

Notes

• The script is automatically executed at boot. Implement this requirement according to the type of operating system.
• The script must mount /dev/cdrom, and read os_action/os.conf file under the mount point to obtain configuration information.
• The password placed in the cdrom by Converge Cloud is an encrypted password. Users can use chpasswd -e to set it.
  The encrypted password may contain special characters. It is recommended to put it in a file first and then use chpasswd -e < passwd_file to set it.
• When recreating an image using an instance created by forced import image, you need to ensure that the script is still executed to ensure that the instance is correctly configured. You can also install cloudinit in this instance.

Example

Converge Cloud provides a sample script based on CentOS. Users can create configuration scripts for their own images based on the sample script. During the creation process, note the following points:

• This script needs to be correctly placed in the system before importing the image.
• This script is not suitable for all operating systems. Users need to modify it according to their own operating system to meet the semantics.

1. Create os_config script according to the following script example.
   Users can modify os_config script according to actual conditions.

   #!/bin/bash
   ### BEGIN INIT INFO
   # Provides:          os-config
   # Required-Start:    $local_fs $network $named $remote_fs
   # Required-Stop:
   # Should-Stop:
   # Default-Start:     2 3 4 5
   # Default-Stop:      0 1 6
   # Short-Description: config of os-init job
   # Description: run the config phase without cloud-init
   ### END INIT INFO
   ###################user settings#####################
   cdrom_path=`blkid -L config-2`
   load_os_config() {
       mount_path=$(mktemp -d /mnt/tmp.XXXX)
       mount /dev/cdrom $mount_path
       if [[ -f $mount_path/qcloud_action/os.conf ]]; then
           . $mount_path/qcloud_action/os.conf
           if [[ -n $password ]]; then
               passwd_file=$(mktemp /mnt/pass.XXXX)
               passwd_line=$(grep password $mount_path/qcloud_action/os.conf)
               echo root:${passwd_line#*=} > $passwd_file
           fi
           return 0
       else 
           return 1
       fi
   }
   cleanup() {
       umount /dev/cdrom
       if [[ -f $passwd_file ]]; then
           echo $passwd_file
           rm -f $passwd_file
       fi
       if [[ -d $mount_path ]]; then
           echo $mount_path
           rm -rf $mount_path
       fi
   }
   config_password() {
       if [[ -f $passwd_file ]]; then
           chpasswd -e < $passwd_file
       fi
   }
   config_hostname(){
       if [[ -n $hostname ]]; then
           sed -i "/^HOSTNAME=.*/d" /etc/sysconfig/network
           echo "HOSTNAME=$hostname" >> /etc/sysconfig/network
       fi
   }
   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" >> $dns_conf
           done
       fi
   }
   config_network() {
       /etc/init.d/network stop
       cat << EOF > /etc/sysconfig/network-scripts/ifcfg-eth0
   DEVICE=eth0
   IPADDR=$eth0_ip_addr
   NETMASK=$eth0_netmask
   HWADDR=$eth0_mac_addr
   ONBOOT=yes
   GATEWAY=$eth0_gateway
   BOOTPROTO=static
   EOF
       if [[ -n $hostname ]]; then
           sed -i "/^${eth0_ip_addr}.*/d" /etc/hosts
           echo "${eth0_ip_addr} $hostname" >> /etc/hosts
       fi
       /etc/init.d/network start
   }
   config_gateway() {
       sed -i "s/^GATEWAY=.*/GATEWAY=$eth0_gateway" /etc/sysconfig/network
   }
   ###################init#####################
   start() {
       if load_os_config ; then
           config_password
           config_hostname
           config_dns
           config_network
           cleanup
           exit 0
       else 
           echo "mount ${cdrom_path} failed"
           exit 1
       fi
   }
   RETVAL=0
   case "$1" in
       start)
           start
           RETVAL=$?
       ;;
       *)
           echo "Usage: $0 {start}"
           RETVAL=3
       ;;
   esac
   exit $RETVAL
   

2. Place os_config script in /etc/init.d/ directory and execute the following command.

   chmod +x /etc/init.d/os_config
   chkconfig --add os_config
   

3. Execute the following command to check whether os_config has been added to the startup services.

   chkconfig --list
   

Note: Users need to ensure that the script is executed correctly. If the instance cannot be connected through SSH or the network connection is unavailable after the image is imported, connect to the instance through the console and run the script again to troubleshoot. If the problem still cannot be solved, contact customer service.