Howto: Configure CloudLinux kernel on pv xen

In other to switch your hosted server with pv xen to CloudLinux server, you may refer to the step as below,

1. Make sure that /etc/sysconfig/kernel is as line below, if the file is not exist, create it,

UPDATEDEFAULT=yes
DEFAULTKERNEL=kernel-xen

2. Install grub if it is not,

yum install grub

3. Check /etc/modprobe.conf is exists and with the following line it is not,

alias eth0 xennet
alias scsi_hostadapter xenblk

4. If you have install the newer kernel, run the following line,

mkinitrd -f /boot/initrd-2.6.xxx.img 2.6.xxx

‘xx’ should be the same as you newly installed kernel-xen version

5. Else, install kernel,

yum install kernel-xen

6. Check if /boot/grub/grub.conf exists, else create it,

ln -s /boot/grub/grub.conf /boot/grub/menu.lst
ln -s /boot/grub/grub.conf /etc/grub.conf

7. Make sure that the /etc/grub.conf is look like,

default=0
timeout=10
title CentOS (2.6.18-308.11.1.el5xen)
root (hd0,0)
kernel /boot/vmlinuz-2.6.18-308.11.1.el5xen console=xvc0 root=/dev/sda1 ro
initrd /boot/initrd-2.6.18-308.11.1.el5xen.img

Make sure that the vmlinuz and initrd should be the same.

8. Ask your hosting provider to change the kernel type to pygrub and reboot it.

R1Soft: Replication driver missing

I was discovery that the R1Soft server hosted for client server getting the following error,

An exception occurred during the request. Replication driver missing; Unable to open driver at '/dev/hcp'; No such device or address.

To get this issue fixed, you should make sure that you have the kernel similar version with your kernel-header. Then you could verify if the Linux Hot Copy module is loaded. To verify the them,

To check the kernel version,

uname -r

To check the kernel-header version,

yum list kernel-devel

If you have PAE, xen or Enterprise kernel, use the corresponding version like kernel-PAE-devel, kernel-xen-devel or kernel-ent-devel.

Next, build the kernel header with source,

r1soft-setup --get-module --no-binary

Next, restart the CDP-Agent to load the new driver,

/etc/init.d/cdp-agent restart

After that, you may check if the module loaded

lsmod | grep hcpdriver

You have done and the error should away by now.