Difference between revisions of "OpenSolaris zones"

Revision as of 18:06, 18 November 2009

Why I wrote this document, and why you should consider OpenSolaris

Q. Why did I write this?
A. Several reasons, here are a few of them.

First and foremost, choice: OpenSolaris is a tool to be used in whatever endeavor you may want to tackle with it. In the context of this article, using it as a platform for VistA.
To inform: Relatively few people know anything about OpenSolaris and even fewer even know that it exists. This is something I think that it shares with VistA. They are both extremely powerful software environments, and are so expansive that it would be nearly impossible for any one person to know everything. That very expansiveness fosters a community of users, from all parts of the world.
To share: I have been using OpenSolaris for over a year now, and previously used Solaris 10 since 2007. I have gained a lot of experience with the OS, and think that I may be able to provide help and insight as to different ways to attack a given problem.

Q. Why should you consider OpenSolaris?
A. I think a better question might be, why shouldn't you try OpenSolaris. If your reading this than you must be at least slightly interested, so here are a few reasons why you should try it.

OpenSolaris was designed from the beginning for enterprise computing.
ZFS "The last word in filesystems!"
Dtrace Wanna know what your program is doing? Dtrace allows developers and system admins, ways to look at running programs in ways that weren't possible before.
xVM The OpenSolaris version of the popular Xen hypervisor.
Zones/Containers. OS level virtualization, zones allow for completely isolated instances for running software. This is similar to the xVM hypervisor in that it allows absolute containment of applications and utilities, the biggest difference being, xVM requires a separate kernel, and running operating system. Zones utilize a single operating system instance, and don't incur the overhead associated with a hypervisor based model. However, xVM and Zones are NOT mutually exclusive, and work quite well in parallel. Zones are the main focus of this document.
Crossbow: The new virtualized networking stack built into the current released of OpenSolaris
Support: You can get help from the forums, support contracts from Sun, and as with most any other question, Google is an invaluable resource.
BrandZ: An extension of the zone/container framework. Designed to support Linux applications on the OpenSolaris platform. People have run apps, ranging from Apache for Linux, to Unreal Tournament 2004 (playable with audio), to modern day game servers, to GT.M. There is a pretty high likelihood that if you can do it in Linux, you can do it in a zone/container.

What this document is

This is a brief how to on settting up lx26 zones on OpenSolaris. (That's a lower case "L" and is a reference to LinuX kernel 2.6). The goal here is to facilitate a Linux based VistA implementation on x86, and x64 OpenSolaris platforms. SPARC based systems are not covered.

What this document is not

This document is not meant to be the be-all-end-all of zone documentation. There is a great deal more to the technology than I'm even going to begin to cover in this write up. If you want to know more about lx26 zones, you can find lots of information here.

These instructions are not meant for Amazon's EC2. The architecture of EC2 requires several additional steps, however the details of such are well beyond the scope or intent of this document.

What are zones?

A virtualized operating system environment
Each zone has its own characteristics e.g. zonename, IP addresses, hostname, naming services, root and non-root users
Isolated application environments within a single OS instance

Document Conventions

When I use the term “virtual machine”, unless specifically labeled otherwise, I'm talking about OS level virtualization, as opposed to VirtualBox, or the Xen and vmWare hypervisors. In the latter 3 cases I will refer to them by name.

What's needed

Before beginning the install process you need several things, most of which are covered in this how-to:

Time. How much depends on several factors, including your skill and comfort level with OpenSolaris and the UNIX CLI, the machine used for testing, and probably several other factors I'm overlooking.
You need internet access on the machine where you will be doing the installation.
You need to have a 32bit CentOS 5.x filesystem tarball. At the time of this writing you can download the tarball right here. Note that 64-bit support is still in development and currently unstable.
You need to decide where in the filesystem you want the zones to be created. Each zone needs a minimum of about 10Gb, give or take depending on your personal circumstances. After complete setup I've personally found that 6Gb is enough space when using ZFS compression.
You need to obtain a unique static IP address for each zone.
You need to decide how your going to name your zones. Zones are a method of virtualization, and should be treated as if they were individual systems. (IP, hostnames, etc.) This is no different than if you were using Xen or vmWare.
You need to decide if you want the zones to start up on boot of the main system, or if you want to boot them manually after system start up. In a testing environment this is purely a matter of preference.
You need to decide what method you are going to use to install VistA. (Astronaut, Nancy's instructions, Medsphere's installation method etc.) I will briefly cover the 3 at the end of this how-to.
You need to be aware that the terms Zones and Containers are often used interchangeably, the difference being a container is a zone with resource management tools applied. Resource management is not covered in this document.

Assumptions

Setting and configurations based on how I did this: (Adjust to your specific situation)

You have either root level access, or you have been assigned RBAC privileges for zones on an OpenSolaris machine.
You know how to add users and set permissions on a directory.
You are using a network link aggregation (also known as link bonding in Linux) named aggr0, and that your network is 192.168.1.0 with a netmask of 255.255.255.0
The IP address that is used in this demo is 192.168.1.7/24, this is the IP that will be used throughout these examples.
The fs path I used for the zone files is, /zones ( I know it just reeks of creativity :)
For purposes of this demonstration I have simply called the zone, zone1. You should name it something meaningful, perhaps even name the zone whatever the hostname of the “virtual machine” will be. Use a naming scheme that works for you. This is purely preferential.
The CentOS 5.x tarball will be downloaded to /export/home/butch/software/
The username that I used for the demo is butch, cause using something other than my name seemed a tad silly...substitute whatever name you feel appropriate, where it's appropriate.

Setting up the virtualization environment

To enable lx26 zone support

Download the template file

user@computer# cd /etc/zones
user@computer# wget http://www.opensolaris.org/os/community/brandz/files/SUNWlx26.xml
user@computer# chown root:bin SUNWlx26.xml
user@computer# chmod 444 SUNWlx26.xml

Create the zone

This section shows the commands to use, and the relative output:

user@computer# zonecfg -z zone1
zone1: No such zone configured
Use 'create' to begin configuring a new zone.
zonecfg:zone1>create -t SUNWlx26
zonecfg:zone1>set zonepath=/zones/zone1
zonecfg:zone1>set autoboot=true
zonecfg:zone1>add net
zonecfg:zone1:net>set address=192.168.1.7/24
zonecfg:zone1:net>set physical=aggr0
zonecfg:zone1:net>end
zonecfg:zone1>verify
zonecfg:zone1>commit
zonecfg:zone1>exit

Install the zone:

Download and install a CentOS 5.x tarball

user@computer# cd /export/home/butch/software/
user@computer# wget http://download.openvz.org/template/precreated/centos-5-x86.tar.gz
user@computer# zoneadm -z zone1 install -d /export/home/butch/software/centos-5-x86.tar.gz
Preparing to install zone <zone1>.

Depending on your computer's overall speed, this process may take only a few short minutes, or “a considerable amount of time”...

Pre-boot zone setup

Edit the following files to complete the networking setup:

user@computer# vi /zones/zone1/root/etc/sysconfig/network
NETWORKING=yes
HOSTNAME=zone1
GATEWAY=192.168.1.1

user@computer# vi /zones/zone1/root/etc/nsswitch.conf (Edit the hosts line to read)
hosts: files dns nis

user@computer# vi /zones/zone1/root/etc/resolv.conf (Edit the file according to your network configuration.  
I used public nameservers for this demo.)
domain opendns.org
nameserver 208.67.220.220
nameserver 208.67.222.222

Booting and logging in to the zone

At this point the zone should be configured and installed. Now it's time to log into the zone, which can be done as a 1 or 2 part process.

First, you need to ensure the zone is running: You should see output similar to the following.

user@computer# zoneadm list
global
zone1

If zone1 is not listed in the output, then it's not yet running. To bring it online use:

user@computer# zoneadm -z zone1 boot

Wait a few seconds, and re-run the zoneadm list command. Once the zone is running, log into it using the zlogin -S command.

user@computer# zlogin -S zone1
sh-3.2#

At this point, you have a login that resembles a Linux run level 1 command prompt. The reason for logging in this way is to reset the root password to something of a known value.

sh-3.2# passwd root

Changing password for user root.
New UNIX password: 
Retype new UNIX password: 
passwd: all authentication tokens updated successfully.
sh-3.2#

Finishing up

At this point you need logout and back into the virtual machine, either by SSH or by zlogin without the -S flag.

user@computer# zlogin zone1

It is necessary to do so as logging in with zlogin -S gives you the equivalent of a single user Linux environment, and many of the tools and such wont work.

Now that the zone is running, and the root password is set, it's time to run some basic commands. Start by making sure that all the existing packages are up to date.

user@computer# yum update

This process may take a considerable amount of time, but it's well worth doing. Unless you have specific reasons to not do so, (you already know that an updated package is going to interfere with whatever else your doing, etc.) update the system. Current testing shows no negative impact on rpm based VistA installations.

Now your zone is ready to take for a spin. Even though this document was written with installing VistA in mind, you now have a Linux 2.6 environment you can use for most anything you want. There are some additional steps that need to be undertaken if you want to use audio programs and such, much of that is covered in the forums here. The next section has some very brief information about installing VistA inside of the completed zone.

OpenSolaris Zones and VistA installation overview

Basically this section contains brief notes about installing VistA via 3 different methods. Astronaut installer, the manual installation method authored by Nancy Anthracite, and the installation method for installing Medsphere's OpenVistA package, without using the astronaut installer. This over view is not intended to say that one method is better than another, it's only here to let you know what methods I have tried in the zone environment. Each method has its place, and a time to use it. That however is up to the end user to decide.

Nancy's installation instructions

This method, is probably the oldest written installation method available, and is likewise in turn, probably responsible for more installations than we will ever know. However, being that it is a completely manual process, it is prone to errors, if you don't follow the instructions explicitly. Cut and paste will be your friend with this method. My thanks to Nancy for producing this document.

The Astronaut auto-installer

This method was the first fully automated method that I am aware of, and is developed and maintained by Ignacio Valdes. Using the functionality of dpkg and rpm (and their corresponding front ends) Ignacio has automated the entire installation process. What started as an all in one installer that was designed to get the product into the hands of as many people as possible, is quickly maturing, and is beginning to be broken out into it's component pieces. This will make it much more appealing to sys admins, who don't want to install extra software on their systems, and it should make maintaining an Astronaut based, VistA system easier. There is a version of the Astronaut installer for both WorldVistA and Medsphere's OpenVistA server products. This installer seems to work out of the box, within the OpenSolaris zone environment with no problems, that are not present in a standard installation on any other system. My thanks to Ignacio for producing this installer, as well as allowing me to be involved as much as I have. Which has included ripping apart and analyzing almost every version of the installer that he has released so far, and offering input and insight from a sys admins point of view.

The Medsphere installation method

This method is similar to the Astronaut installation method, in that many of the tasks are automated. Installing Medsphere's OpenVistA packages is somewhat more involved than using Astronaut, but not nearly as involved as the manual method. Installing the OpenVistA server packages requires manually adding the EPEL software repo as well as the yum-priorities package. Current testing within a zone environment also shows some problems with Medsphere's packages. NOTE: These problems are not inherent in the packages themselves. Testing on a full CentOS 5.3 environment does not show problems. Using these packages within a zone environment is not how they were initially intended to be used. I am working with the OpenSolaris community as well as Medsphere to try to work these things out, but it's going to take time. My thanks to Medsphere's OpenVistA team for producing this software, and for working with me in testing it on OpenSolaris.

-- Butch Whitby