Difference between revisions of "OpenVZ"

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(Created page with "=== Introduction === OpenVZ is an open-source virtualization system for Linux. It is kernel and container based. It is not a hypervisor-based system. The kernel is shared amon...")

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OpenVZ is a lightweight, secure, high-performance virtualization system for Linux. See also the [http://openvz.org OpenVZ Website].

=== Introduction ===

−

OpenVZ is an open-source virtualization system for Linux. It is kernel and container based. It is not a hypervisor-based system. The kernel is shared among the host and its guests. Guests may run any distribution of Linux compatible with the kernel being run on the host.

+

(Broomfield, 03/14/2013) OpenVZ is an open-source virtualization system for Linux. It is kernel and container based. It is not a hypervisor-based system. The kernel is shared among the host and its guests. Guests may run any distribution of Linux compatible with the kernel being run on the host.

The major benefits of OpenVZ are:

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==== Uncategorized Factoids ====

Container numbers (CT or CTID) are mapped to the host system's UID's (User IDs). They are specified as starting with 100 and increasing. Since I have installed on clean systems, I can't say what happens if you try to create a container with an ID number that already exists for a host username.

+

==== The Author ====

+

This page is under construction. Author: Gregg Squires

+

=== Quick-Start User Guide ===

−

~~Under Heavy Construction :) -~~ The good news is that (what should be) routine tasks like creating, starting, stopping and destroying a container... along with administering it... are all very easy and require very little typing in OpenVZ. Network setup for containers providing services to the network is automatic. This implies that you must be disciplined in allocating and documenting IPs used by containers. With power comes the requirement for responsibility!

+

The good news is that (what should be) routine tasks like creating, starting, stopping and destroying a container... along with administering it... are all very easy and require very little typing in OpenVZ. Network setup for containers providing services to the network is automatic. This implies that you must be disciplined in allocating and documenting IPs used by containers. With power comes the requirement for responsibility!

==== Create a Container ====

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logout

exited from CT 101

+

</pre>

+

Before we move on... where do the files go? ls /vz/private and you'll see a directory "101", that's where the file structure for container, or CT #101 lives on the host machine. Now, let's destroy that container, as it was just a simple example!

+

<pre>

+

# vzctl destroy 101

</pre>

Pretty simple! Now lets start flipping switches and twisting knobs...

+

<b>A More Complex Example...</b>

To specify the distro and config of the CT, Execute the following commands to view the templates and distros available:

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<pre>

# vzctl create 101 --ostemplate centos-6-x86_64 --config basic

+

# vzctl start 101

+

# vzctl enter 101

</pre>

Note that '.tar.gz' was not included in the ostemplate specification. For the config arg, the "ve-" prefix and "-sample" were not included. Note also that 107 is the CT id, and it's above 100. All CT numbers below 100 are reserved! The defaults for these parameters can be set in /etc/sysconfig/vz so the host system administrator should set appropriate defaults there.

+

And what about that '--config' arg? Look in ''/etc/vz/conf'' to see what's available. It's a link to ''/etc/sysconfig/vz-scripts'' as mentioned above. You can start with one of those templates and create your own.

+

Getting on the network isn't too hard. The key commands are:

+

<pre>

+

# vzctl set 101 --ipadd 1.2.3.4 --nameserver 5.6.7.8 --save

+

</pre>

=== Installation on CentOS 6.3 ===

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Run the following command

<pre>

−

# yum install ~~[o]~~vzkernel~~[-flavor]~~

+

# yum install vzkernel

</pre>

+

Before answering 'y' check that the arch is correct. If there is an issue, consider those surrounding the "yum install [o]vzkernel[-flavor]" variants.

+

==== Configuring ====

Please make sure the following steps are performed before rebooting into OpenVZ kernel.

−

~~'''~~sysctl~~'''~~

+

===== /etc/sysctl.conf =====

There are a number of kernel parameters that should be set for OpenVZ to work correctly. These parameters are stored in /etc/sysctl.conf file. Here are the relevant portions of the file; please edit accordingly.

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SELINUX=disabled

</pre>

+

==== Reboot into OpenVZ kernel ====

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OpenVZ needs some user-level tools installed. Those are:

−

vzctl

+

'''vzctl'''

−

A utility to control OpenVZ containers (create, destroy, start, stop, set parameters etc.)

+

*A utility to control OpenVZ containers (create, destroy, start, stop, set parameters etc.)

−

vzquota

+

−

A utility to manage quotas for containers. Mostly used indirectly (by vzctl).

+

'''vzquota'''

+

*A utility to manage quotas for containers. Mostly used indirectly (by vzctl).

<pre>

# yum install vzctl vzquota

−

+

</pre>

If on the x86_64 platform you would probably want to:

−

+

<pre>

# yum install vzctl.x86_64 vzquota.x86_64

</pre>

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An OS template cache is a Linux distribution installed into a container and then packed into a gzipped tarball. Using such a cache, a new container can be created in a matter of minutes.

−

Download precreated template caches from Downloads » Templates » Precreated, or directly from download.openvz.org/template/precreated, or from one of the mirrors. Put those tarballs as-is (no unpacking needed) to the /vz/template/cache/ directory (for ~~Debain~~, this is /var/lib/vz/template/cache/).

+

Download precreated template caches from Downloads » Templates » Precreated, or directly from download.openvz.org/template/precreated, or from one of the mirrors. Another possible source is a another OpenVZ host nearby. You probably don't need them all, so you may want to be selective. Put those tarballs as-is (no unpacking needed) to the /vz/template/cache/ directory (for Debian, this is /var/lib/vz/template/cache/). Here's an example to get fedora templates onto OpenVZ running on CentOS:

−

Next ~~steps~~

+

<pre>

+

$ cd /vz/template/cache

+

$ wget http://download.openvz.org/template/precreated/fedora*

+

</pre>

+

==== Next Steps ====

−

OpenVZ is now set up on your machine. To load OpenVZ kernel by default, edit the default line in the /boot/grub/grub.conf file to point to the OpenVZ kernel. For example, if the OpenVZ kernel is the first kernel mentioned in the file, put it as default 0. See man grub.conf for more details.

+

OpenVZ is now set up on your machine. To load OpenVZ kernel by default, edit the default line in the /boot/grub/grub.conf file to point to the OpenVZ kernel. For example, if the OpenVZ kernel is the first kernel mentioned in the file, put it as default 0. See man grub.conf for more details.

==== Source Reference(s) ====

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==== Contrib Distros ====

−

There are "minimal" configuration distros that may be of use, and are available in the 'contrib' distro directory. Many of those that are in the RedHat family do not include an install of 'yum'~~. Does this mean you have to install packages by downloading RPMs? No. Use the force, Luke! In this case, use the 'vzyum' command when in the CT (container) system~~.

+

There are "minimal" configuration distros that may be of use, and are available in the 'contrib' distro directory. Many of those that are in the RedHat family do not include an install of 'yum'.

Difference between revisions of "OpenVZ"

Revision as of 15:33, 6 May 2013

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@@ Line 1: / Line 1: @@
+OpenVZ is a lightweight, secure, high-performance virtualization system for Linux. See also the [http://openvz.org OpenVZ Website].
 === Introduction ===
-OpenVZ is an open-source virtualization system for Linux. It is kernel and container based. It is not a hypervisor-based system. The kernel is shared among the host and its guests. Guests may run any distribution of Linux compatible with the kernel being run on the host.
+(Broomfield, 03/14/2013) OpenVZ is an open-source virtualization system for Linux. It is kernel and container based. It is not a hypervisor-based system. The kernel is shared among the host and its guests. Guests may run any distribution of Linux compatible with the kernel being run on the host.
 The major benefits of OpenVZ are:
@@ Line 25: / Line 26: @@
 ==== Uncategorized Factoids ====
 Container numbers (CT or CTID) are mapped to the host system's UID's (User IDs). They are specified as starting with 100 and increasing. Since I have installed on clean systems, I can't say what happens if you try to create a container with an ID number that already exists for a host username.
+==== The Author ====
+This page is under construction. Author: Gregg Squires
 === Quick-Start User Guide ===
-Under Heavy Construction :) - The good news is that (what should be) routine tasks like creating, starting, stopping and destroying a container... along with administering it... are all very easy and require very little typing in OpenVZ. Network setup for containers providing services to the network is automatic. This implies that you must be disciplined in allocating and documenting IPs used by containers. With power comes the requirement for responsibility!
+The good news is that (what should be) routine tasks like creating, starting, stopping and destroying a container... along with administering it... are all very easy and require very little typing in OpenVZ. Network setup for containers providing services to the network is automatic. This implies that you must be disciplined in allocating and documenting IPs used by containers. With power comes the requirement for responsibility!
 ==== Create a Container ====
@@ Line 47: / Line 52: @@
 logout
 exited from CT 101
+</pre>
+Before we move on... where do the files go? ls /vz/private and you'll see a directory "101", that's where the file structure for container, or CT #101 lives on the host machine. Now, let's destroy that container, as it was just a simple example!
+<pre>
+# vzctl destroy 101
 </pre>
 Pretty simple! Now lets start flipping switches and twisting knobs...
+<b>A More Complex Example...</b>
 To specify the distro and config of the CT, Execute the following commands to view the templates and distros available:
@@ Line 59: / Line 70: @@
 <pre>
 # vzctl create 101 --ostemplate centos-6-x86_64 --config basic
+# vzctl start 101
+# vzctl enter 101
 </pre>
 Note that '.tar.gz' was not included in the ostemplate specification. For the config arg, the "ve-" prefix and "-sample" were not included. Note also that 107 is the CT id, and it's above 100. All CT numbers below 100 are reserved! The defaults for these parameters can be set in /etc/sysconfig/vz so the host system administrator should set appropriate defaults there.
+And what about that '--config' arg? Look in ''/etc/vz/conf'' to see what's available. It's a link to ''/etc/sysconfig/vz-scripts'' as mentioned above. You can start with one of those templates and create your own.
+Getting on the network isn't too hard. The key commands are:
+<pre>
+# vzctl set 101 --ipadd 1.2.3.4 --nameserver 5.6.7.8 --save
+</pre>
 === Installation on CentOS 6.3 ===
@@ Line 76: / Line 95: @@
 Run the following command
 <pre>
-# yum install [o]vzkernel[-flavor]
+# yum install vzkernel
 </pre>
+Before answering 'y' check that the arch is correct. If there is an issue, consider those surrounding the "yum install [o]vzkernel[-flavor]" variants.
 ==== Configuring ====
 Please make sure the following steps are performed before rebooting into OpenVZ kernel.
-'''sysctl'''
+===== /etc/sysctl.conf =====
 There are a number of kernel parameters that should be set for OpenVZ to work correctly. These parameters are stored in /etc/sysctl.conf file. Here are the relevant portions of the file; please edit accordingly.
@@ Line 109: / Line 130: @@
 SELINUX=disabled
 </pre>
 ==== Reboot into OpenVZ kernel ====
@@ Line 119: / Line 141: @@
 OpenVZ needs some user-level tools installed. Those are:
-vzctl
+'''vzctl'''
-    A utility to control OpenVZ containers (create, destroy, start, stop, set parameters etc.)
+*A utility to control OpenVZ containers (create, destroy, start, stop, set parameters etc.)
-vzquota
-    A utility to manage quotas for containers. Mostly used indirectly (by vzctl).
+'''vzquota'''
+*A utility to manage quotas for containers. Mostly used indirectly (by vzctl).
 <pre>
 # yum install vzctl vzquota
+</pre>
 If on the x86_64 platform you would probably want to:
+<pre>
 # yum install vzctl.x86_64 vzquota.x86_64
 </pre>
@@ Line 149: / Line 172: @@
 An OS template cache is a Linux distribution installed into a container and then packed into a gzipped tarball. Using such a cache, a new container can be created in a matter of minutes.
-Download precreated template caches from Downloads » Templates » Precreated, or directly from download.openvz.org/template/precreated, or from one of the mirrors. Put those tarballs as-is (no unpacking needed) to the /vz/template/cache/ directory (for Debain, this is /var/lib/vz/template/cache/).
+Download precreated template caches from Downloads » Templates » Precreated, or directly from download.openvz.org/template/precreated, or from one of the mirrors. Another possible source is a another OpenVZ host nearby. You probably don't need them all, so you may want to be selective. Put those tarballs as-is (no unpacking needed) to the /vz/template/cache/ directory (for Debian, this is /var/lib/vz/template/cache/). Here's an example to get fedora templates onto OpenVZ running on CentOS:
-Next steps
+<pre>
+$ cd /vz/template/cache
+$ wget http://download.openvz.org/template/precreated/fedora*
+</pre>
+==== Next Steps ====
 OpenVZ is now set up on your machine. To load OpenVZ kernel by default, edit the default line in the /boot/grub/grub.conf file to point to the OpenVZ kernel. For example, if the OpenVZ kernel is the first kernel mentioned in the file, put it as default 0. See man grub.conf for more details.
 ==== Source Reference(s) ====
@@ Line 193: / Line 222: @@
 ==== Contrib Distros ====
-There are "minimal" configuration distros that may be of use, and are available in the 'contrib' distro directory. Many of those that are in the RedHat family do not include an install of 'yum'. Does this mean you have to install packages by downloading RPMs? No. Use the force, Luke! In this case, use the 'vzyum' command when in the CT (container) system.
+There are "minimal" configuration distros that may be of use, and are available in the 'contrib' distro directory. Many of those that are in the RedHat family do not include an install of 'yum'.