Check Virtualization type for a running Linux

joseph — Sat, 10 Dec 2011 14:53:55 +0000

Are you running VPS as a hosting solution? And do you want to know what kind of virtualization is it running on? Is it OpenVZ, V-server, Xen or UML, and how can I confirm this?
Since the hosting providers normally do not tell you these kind of detailed info, here we created a simple script:

#!/usr/bin/python
#
# Check what kind of virtual machine for a running Linux. It supports (openvz/vserver/xen/uml).
# Please copy & save this script and run it as root.
#
# By Joseph Chen  2011-12-10

import sys, os
import re

def main():
    if os.getuid() != 0:
        print "It must be run as root"
        sys.exit(0)

    # Check OpenVZ/Virtuozzo
    if os.path.exists("/proc/vz"):
        if not os.path.exists("/proc/bc"):
            print "openvz container"
        else:
            print "openvz node"

    # Check V-server
    if os.path.exists("/proc/self/status"):
	s = open("/proc/self/status", "r")
	txt = s.read()
	s.close()

        reobj = re.compile(r"^(s_context|VxID):[[:blank:]]*[0-9]/")
        if reobj.match (txt):
            if os.path.exists("/proc/virtual"):
                print "vserver_host"
            else:
                print "vserver"

    # Check Xen
    if os.path.exists("/proc/xen/capabilities"):

	f = open("/proc/xen/capabilities", "r")
	text = f.read()
	f.close()

        if (len(text) > 0):
            print "xen dom0"
        else:
            print "xen domU"

    # Check User Mode Linux (UML)
    f = open("/proc/cpuinfo", "r"); t = f.read(); f.close()
    if (t.find("UML") > 0):
        print "uml"

if __name__=="__main__":
    main()

Here is a running example on a Xen dom0 node:

root@pekdev230:~ # python check-vm.py
xen dom0

Note that, the check for vserver may not work since I didn’t get an environment for testing. Sorry about that, but if you any updates, please kindly let me know.

Rename a Vserver step by step

joseph — Wed, 06 Jan 2010 03:39:09 +0000

Suppose you made a mistake on the Vserver name when creating it. After finished the installation, you might want to rename your Vserver. This can be accomplished by renaming the config directory and the root for the vserver in question, then modifying some symlinks to match.

The general steps are:

Stop the vserver in question

It can be done by this command: “vserver stop”

Rename the /vservers/ directory

By default it’s in /vservers, and on some self-crafted versions, it might be re-defined to other path like /var/lib/vservers. Simply you just need to use mv command to rename the issued vserver.

Rename the /etc/vservers/ directory

The directory /etc/vservers is much like a system wide configuration directory for vservers, you can use mv to rename specified directory as well.

Update some softlink in /etc/vservers/

update link: /etc/vservers//run -> /var/run/vservers/
update link: /etc/vservers//vdir -> /etc/vservers/.defaults/vdirbase/
update link: /etc/vservers//cache -> /etc/vservers/.defaults/cachebase/
Pay some attention to relative path issue, otherwise these links might get broken, there’s an example, the current working directory is /etc/vservers/mars:

joseph@galaxy:/etc/vservers/mars$ ln -s -f /etc/vservers/.defaults/vdirbase/mars vdir

Update link: /var/run/vservers.rev/ -> /etc/vservers/

Please note that this just an update by fixing the dead link, and there’s no need to create a new XID.

Reset hostname for vserver in question

Basically you just need to modify /etc/vservers//uts/nodename before starting the issued vserver, and get other host name related settings modified when system booted.

joseph@galaxy:/etc/vservers$ grep mars -R mars/ 2>/dev/null -l
mars/uts/nodename
mars/vdir/etc/hosts
mars/vdir/etc/pam_ldap.conf
mars/vdir/etc/mailname
mars/vdir/etc/hostname

Now, It should start properly. If any issue encountered, please don’t hesitate to raise a forum thread at our community forum.

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Check Virtualization type for a running Linux

Rename a Vserver step by step