How to upgrade Kernel (Xen Node) (Tested)

First of all these things, make sure you have console/IPMI/iKVM access to the server (In-case of emergency)

1. First check the current Kernel version,

[root@server xen]# uname -r
3.10.34-11.el6.centos.alt.x86_64

2. Then stop the whole VM's / Xend service.

# service xendomains stop
# chkconfig xend off
# chkconfig xendomains off

3. Update the Kernel using Yum update (Make sure you have access to IPMI/Console)

# yum -y update kernel-xen

4. Reboot the server

#reboot

5. Then start the stoped services at step #2

# service xendomains start
# chkconfig xend on
# xhkconfig xendomains on

Check the current version,

[root@Ganga xen]# uname -r
3.10.68-11.el6.centos.alt.x86_64

In case of errors run /script/fixxenkernel

VM's won't be booting along with the reboot, you need to manually start the VM's using configuration file.

[root@Ganga xen]# xm create /home/xen/vm325/vm325.cfg
WARNING: xend/xm is deprecated.
Using config file "/home/xen/vm325/vm325.cfg".
Started domain vm325 (id=1)

You will get the domain list from Solusvm or from /home/xen.