# What Do I Do If the Disks of an ECS Created from a CentOS Image Cannot Be Found?

#### Symptom

Generally, this is because the xen-blkfront.ko module is not loaded during the startup. You need to modify OS kernel startup parameters. Figure 1 shows the startup screen after the login to the ECS.

Figure 1 Startup screen

#### Solution

Perform the following operations to modify OS kernel boot parameters:

These operations must be performed after the OS starts. You are advised to modify kernel boot parameters in the ECS used for creating the image.

1. Run the following command to log in to the OS:
   lsinitrd /boot/initramfs-`uname -r`.img |grep -i xen
   - If the command output contains xen-blkfront.ko, contact the customer service.
   - If no command output is displayed, go to 2.
2. Back up the GRUB configuration file.
   - If the ECS runs CentOS 6, run the following command:

     cp /boot/grub/grub.conf /boot/grub/grub.conf.bak

   - If the ECS runs CentOS 7, run the following command:

     cp /boot/grub2/grub.cfg /boot/grub2/grub.cfg.bak

3. Use the vi editor to open the GRUB configuration file. Run the following command (using CentOS 7 as an example):

   vi /boot/grub2/grub.cfg

4. Add xen_emul_unplug=all to the default boot kernel.

   Search for the line that contains root=UUID= and add xen_emul_unplug=all to the end of the line.

       menuentry 'CentOS Linux (3.10.0-229.el7.x86_64) 7 (Core) with debugging' --class centos --class gnu-linux --class gnu --class os --unrestricted $menuentry_id_option 'gnulinux-3.10.0-229.el7.x86_64-advanced-bf3cc825-7638-48d8-8222-cd2f412dd0de' {
               load_video
               set gfxpayload=keep
               insmod gzio
               insmod part_msdos
               insmod ext2
               set root='hd0,msdos1'
               if [ x$feature_platform_search_hint = xy ]; then
                 search --no-floppy --fs-uuid --set=root --hint='hd0,msdos1'  bf3cc825-7638-48d8-8222-cd2f412dd0de
               else
                 search --no-floppy --fs-uuid --set=root bf3cc825-7638-48d8-8222-cd2f412dd0de
               fi
               linux16 /boot/vmlinuz-3.10.0-229.el7.x86_64 root=UUID=bf3cc825-7638-48d8-8222-cd2f412dd0de xen_emul_unplug=all ro crashkernel=auto rhgb quiet  systemd.log_level=debug systemd.log_target=kmsg
               initrd16 /boot/initramfs-3.10.0-229.el7.x86_64.img
       }

5. Press Esc, enter :wq, and press Enter to exit the vi editor.
6. Create an image using the ECS, upload and register the image on the cloud platform.

Parent topic: ECS Creation