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Posts Tagged ‘Xen’

Debian 5.0 xen DomU iptables kernel module problem on fresh install

June 17th, 2009 admin No comments

yesterday i run true a weird situation. After installing fresh DomU with xen-image-create via debootstrap, I noticed that its ipbtales is not working giving the following:

WARNING: Could not open 'kernel/net/netfilter/x_tables.ko': No such file or directory
FATAL: Could not open 'kernel/net/ipv4/netfilter/ip_tables.ko': No such file or directory
iptables v1.3.6: can't initialize iptables table `filter': iptables who? (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.

anyway its very easy to fix and i just decided to share the info, just type a simple command:

depmod

debian xen domU hangs at crond

June 15th, 2009 admin No comments

If you have problems with xen domU console on Debian 5.0 Lenny, stoping at crond, try to add the following line to your config:

extra = 'console=hvc0 xencons=tty'

sshd problem on debian xen guest PTY allocation request failed on channel 0

May 23rd, 2009 admin No comments

How do you fix the issue with a SSH server which freezes after authenticating?

$ ssh root@xxx.xxx.xxx.xxx
The authenticity of host ‘xx.xx.xxx.xxx (xx.xx.xxx.xxx)’ can’t be established.
RSA key fingerprint is replaced for security.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added ‘xx.xx.xxx.xxx’ (RSA) to the list of known hosts.
Password:
PTY allocation request failed on channel 0

In the above scenario, you can see that I logged in but I’m not able to get into the console.

Once you’re in debug more, you will see lots of messages elaborating the SSH access steps in detail. These messages might point you to the root cause or the stage at which you’re being locked.

In my case, I got freezed after authenticating myself.

Resolution is just to make pts and restart sshd

mkdir /dev/pts
mount /dev/pts
/etc/init.d/ssh restart

and permanent solution is just instaling udev via:

apt-get install udev

SSH without password

May 23rd, 2009 admin No comments

Your aim

You want to use Linux and OpenSSH to automize your tasks. Therefore you need an automatic login from host A / user a to Host B / user b. You don’t want to enter any passwords, because you want to call ssh from a within a shell script.

How to do it

First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:

a@A:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa):
Created directory '/home/a/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A

Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):

a@A:~> ssh b@B mkdir -p .ssh
b@B's password:

Finally append a’s new public key to b@B:.ssh/authorized_keys and enter b’s password one last time:

a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys'
b@B's password:

From now on you can log into B as b from A as a without password:

a@A:~> ssh b@B hostname
B

A note from one of our readers: Depending on your version of SSH you might also have to do the following changes:

  • Put the public key in .ssh/authorized_keys2
  • Change the permissions of .ssh to 700
  • Change the permissions of .ssh/authorized_keys2 to 640

CentOS 5.3 Released for i386 / x86_64

April 1st, 2009 admin No comments

We are pleased to announce the immediate availability of CentOS-5.3 for the i386 and x86_64 Architectures.

CentOS-5.3 is based on the upstream release EL 5.3.0, and includes packages from all variants including Server and Client. All upstream repositories have been combined into one, to make it easier for end users to work with. And the option to further enable external repositories at install time is now available in the installer.

This is just an announcement email, not the release notes. The Release Notes for CentOS-5.3 can be found on-line at : http://wiki.centos.org/Manuals/ReleaseNotes/CentOS5.3 and everyone is encouraged to look through them once. Also worth browsing through at the CentOS FAQ’s at http://wiki.centos.org/FAQ

+++++++++++++++++++++++
ArtWork update:

CentOS-5.3 brings in a completely new artwork stack. A big thanks to Alain Reguera Delgado, Ralph Angenendt, Marcus Moeller and everyone on the Artwork SIG for bringing us the best, most comprehensive artwork set yet. Also a big thanks to all the translation teams for their contributions to the installer artwork.

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Contrib repos are back:

Given the widespread requests for user contributed packages directly being hosted within the centos repositories, the contribs repository is now back with CentOS-5.3. There are no packages yet, but over the next few weeks we hope to have a policy and process in place that allows users to submit and manage packages in the contrib repo.

+++++++++++++++++++++++
Upgrading from CentOS-5.2 ( or CentOS-5.0 / 5.1 ):

If you are already running CentOS-5.2 or an older CentOS-5 distro, all you need to do is update your machine via yum by running :

‘yum update’

Running ‘yum list updates’ before doing the update is recommended, so you can get a list of packages that are going to be updated. To check you are indeed on CentOS-5.3, run : ‘rpm -q centos-release’ and that should return: ‘centos-release-5-3.el5.centos.1′

+++++++++++++++++++++++
Upgrading from CentOS-2.1 or CentOS-3.x or CentOS-4.x:

The only recommended way to update from an earlier version of CentOS is to download and run a fresh install. In some cases, running the installer with the ‘upgradeany’ option might also achieve the desired results, however you are strongly recommended to look at the CentOS Wiki where hints and notes about potential upgrade paths from CentOS-4/3/2.1 to CentOS-5 are provided.

+++++++++++++++++++++++
Downloading CentOS-5.3 for new installs:

When possible, consider using torrents to run the downloads. Not only does it help the community and keeps mirrors from running up high bandwidth bills, in most case you will find its also the fastest means to download the distro. There are present over a thousand people already seeding CentOS-5.3 and its possible to get upto 100mbps downloads via
these torrents.

– Via BitTorrent :
CD:
http://mirror.centos.org/centos/5.3/isos/i386/CentOS-5.3-i386-bin-1to6.torrent
http://mirror.centos.org/centos/5.3/isos/x86_64/CentOS-5.3-x86_64-bin-1to7.torrent

DVD:
http://mirror.centos.org/centos/5.3/isos/i386/CentOS-5.3-i386-bin-DVD.torrent
http://mirror.centos.org/centos/5.3/isos/x86_64/CentOS-5.3-x86_64-bin-DVD.torrent

– Via direct download:
Due to bandwidth considerations the CentOS Project does not publish ISOS directly from our network machines. However direct downloads are available from external mirrors over http, ftp and rsync, and a geoip based list is available at http://isoredirect.centos.org/centos/5/isos/ to give you the best predictable match ( and only lists mirrors that are
updated already, so you dont need to waste time looking for a sync’d mirror )

Some mirrors also publish DVD images that can be downloaded directly. Refer to the mirrors list page at http://www.centos.org/mirrors for more details Mirrors that offer DVD’s are clearly marked on the page.

sha1sum for these ISOS:

i386:
4b454d76d06daa0b1772115e9b95c9465a4cecb0 CentOS-5.3-i386-bin-1of6.iso
0da3292ea1d90639714a5e7d77812568bc01ec05 CentOS-5.3-i386-bin-2of6.iso
77e867eb736b58f31cdd25c4835643ab795979e2 CentOS-5.3-i386-bin-3of6.iso
949ee93440e736c8414fb8b571178970a31e6675 CentOS-5.3-i386-bin-4of6.iso
5eafdea33c18f623bb9299ae624b8c8a12132bfa CentOS-5.3-i386-bin-5of6.iso
90ae5387a38f8ec805d877cc5525ae8dedc7f810 CentOS-5.3-i386-bin-6of6.iso
b7f85a3a493e3051e50515ef881214929c88a5f3 CentOS-5.3-i386-bin-DVD.iso
a0c640ae0c68cc0d9558cf4f8855f24671b3dadb CentOS-5.3-i386-netinstall.iso

x86_64:
7327174dc0cbb6531bc0e2f26e24788251717e91 CentOS-5.3-x86_64-bin-1of7.iso
d060ed2826a4c212eebf5e3a825ce75e77cb44e0 CentOS-5.3-x86_64-bin-2of7.iso
a0b7471ec6b742c962cc06b69624b0746025005f CentOS-5.3-x86_64-bin-3of7.iso
fe4106322d6b08344e82df8904142664a8a82522 CentOS-5.3-x86_64-bin-4of7.iso
8cb5539fa4241bc5d23798a3e2721b2ebd3b18fe CentOS-5.3-x86_64-bin-5of7.iso
8a8f32888279f701e15162dec6f52b5f5fb5effc CentOS-5.3-x86_64-bin-6of7.iso
f053b05ea8576ea7d72116fa246f914086238ca9 CentOS-5.3-x86_64-bin-7of7.iso
f8ca12b4acc714f4e4a21f3f35af083952ab46e0 CentOS-5.3-x86_64-bin-DVD.iso
e971bd1677622708348b8a65264ec360a1cc0196 CentOS-5.3-x86_64-netinstall.iso

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Pending CentOS-5.3 Updates and src.rpm’s

Updates have been issued from upstream since they released 5.3, a bulk of these updates are already released into CentOS-5.3 and are available immediately. All pending updates will be released within the next 48 hrs. To keep the initial release size smaller, the src.rpm’s are also going to be slowly released into the mirrors over the next 48 hrs along with debuginfo packages.

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Release Notes:

The distro release notes are only available online at http://wiki.centos.org/Manuals/ReleaseNotes/CentOS5.3 The release notes include important changelog info as well as notes about the installer and outcomes from test situations which the centos-qa team worked through. Its considered essential reading.

Upstream release notes are available in the NOTES/ directory of the install media. These include release specific technologies, new features in the distro and other misc infomation that can help you better utilise the distro.

+++++++++++++++++++++++
Getting Help:

The best place to start when looking for help with CentOS is at the wiki ( http://wiki.centos.org/GettingHelp ) which lists various options and communities who might be able to help. If you think there is a bug in the system, do report it at http://bugs.centos.org/ – but keep in mind that the bugs system is *not* a support mechanism.

Some Friendly URL’s :
http://www.centos.org/
http://wiki.centos.org/
http://lists.centos.org/
http://bugs.centos.org/
irc://#centos@irc.freenode.net

+++++++++++++++++++++++
A big thanks to everyone who contributed, including the translation teams, the qa team, the CentOS Developers and all the users out there. I would also like to thank all the users for their patience and help!

Enjoy this release, tell all your friends about it too.


Karanbir Singh
CentOS Project { http://www.centos.org/ }
irc: z00dax, #centos@irc.freenode.net

Xen Server 5.0 lacks Server 2008 Support

March 1st, 2009 admin No comments

Software is a funny thing sometimes. When you buy a piece of brand new software you think that you are going to get the latest and greatest compatible with all the other latest and greatest software out.

Sadly that is not the case with Citrix’s new Xen 5.0 Virtual server software. There are issues with XenDesktop’s ability to deliver Virtulaized Windows 2008 Server desktops and XenServer will not run the OS Natively. This flaw takes away from the opening up of the RAM support in Xen Express which was limited to 4GB but now supports up to 128GB

This short coming will hurt the VM hopeful as many people currently using VMware and Sun’s Virtual Box have no problems with Microsoft’s latest server OS.

XEN 5.0 compatible operating systems listed here.

There is a work around to this for Citrix’s XenServer if you want to spend the time here.

New Citrix XenServer Release Makes Enterprise-Class, Cloud-Proven Virtualization Free for Everyone

March 1st, 2009 admin No comments

Game Changing Move Goes Well Beyond Free Hypervisors to Accelerate the Adoption of World-Class Virtual Infrastructure for Both Enterprises and Cloud Providers

BOSTON » 2/23/2009 » Citrix Systems, Inc. (Nasdaq: CTXS), the global leader in application delivery infrastructure, today unveiled a groundbreaking new version of Citrix® XenServer™ – the company’s enterprise-class, cloud-proven virtualization platform – that will be offered free of charge to any user for unlimited production deployment.  While basic hypervisors have been free for years, most have had limited practical use in real world environments.  With this new release, XenServer sets an entirely new standard for free virtualization with the addition of powerful new features like centralized multi-node management, multi-server resource sharing and full live motion.  Dramatically lowering the entry price of virtualization also helps address today’s challenging economic climate by making enterprise-class virtualization far more accessible to businesses of all sizes, regardless of budget.

Now in production in more than 5,000 enterprise datacenters worldwide, XenServer is a key component of the Citrix Delivery Center™ product family, a comprehensive datacenter-to-desktop system that helps customers transform static datacenters into dynamic “delivery centers.”  XenServer is powered by the same Xen® virtualization engine that runs most every independent cloud today, including the largest single virtualization deployment in the world.  With more than 75 percent of corporate servers worldwide still not virtualized**, today’s announcement helps accelerate the adoption of virtualization by bringing the simplicity, scale and economics of the cloud to enterprise datacenter for the first time ever.

“Free hypervisors with limited functionality have been around for a long time. We see this move as substantially different because it offers a competitive, enterprise-ready virtual infrastructure platform with full centralized management, live motion and support for unlimited virtual machines and servers – with no strings attached,” said Mark Bowker, analyst, Enterprise Strategy Group.  “This is a very positive move that has the potential to accelerate the adoption of virtualization for enterprise customers of all sizes and make it easier for external cloud providers to add full Windows support to their existing Linux offerings.  Anyone who dismissed XenServer in the past as a legitimate player in enterprise virtualization clearly owes it to themselves to take a look at this offering.”

Enterprise-Class, Cloud-Proven Virtualization
The new Citrix XenServer release provides customers with a robust, scalable, feature-rich virtualization platform that is exceptionally powerful, yet incredibly easy to learn and use. Core features of XenServer include the following:

  • Powerful Centralized Management enables full multi-node management for an unlimited number of servers and virtual machines; includes easy physical-to-virtual and virtual-to-virtual conversion tools, centralized configuration management and a resilient distributed management architecture
  • Live Motion and Multi-Server Resource Sharing incorporates powerful XenMotion™ technology that allows virtual machines to be moved from server to server without service interruption for zero downtime; also includes optimal initial virtual machine placement and intelligent maintenance mode
  • Proven Hypervisor Engine powered by the 64-bit industry standard Xen open source hypervisor developed jointly by more than 50 leading technology vendors, enabling users take full advantage of the latest performance, security and scalability enhancements in next-generation servers, operating systems and microprocessors
  • Fast Bare Metal Performance supports an unlimited number of servers and virtual machines with industry-leading consolidation ratios, near native performance on the most challenging application workloads, and virtually zero overhead in both Microsoft Windows® and Linux environments
  • Easy Setup and Administration features familiar interface with easy wizard-driven configuration, intuitive Web 2.0 style search, and built-in auto-help that makes the learning curve for new administrators a snap
  • Integrated Storage Management that supports any existing storage system; includes built-in storage management features such as host-based logical volume management, and dynamic multi-pathing capabilities

“This move is all about accelerating the adoption of virtualization by tearing down the barriers of cost and complexity that have been in place for far too long,” said Simon Crosby, CTO, Virtualization Management Division, Citrix.  “The faster we can help customers virtualize the millions of servers that remain unvirtualized today, the sooner they can start adding significant value on top, transforming static datacenters into dynamic delivery centers where every application, desktop and server workload is delivered as an on-demand service.”

Good for All Types of Customers
With the new free XenServer release, corporate customers now have everything they need to deploy and centrally manage full enterprise-class virtualization on any number of servers with no upfront costs – especially significant during difficult economic times.  As a result, customers who are new to virtualization can now begin realizing all of its efficiencies and cost savings sooner, upgrading to more advanced virtualization management features when and if they need them down the road.  Customers who have already made an investment in more expensive virtualization platforms in the past, now have a proven enterprise-class alternative to consider when it comes time to upgrade or expand their existing deployments.

The new free XenServer release is also great news for cloud providers, the vast majority of whom use the open source Xen hypervisor today as a core component of their platforms.  By upgrading to the full XenServer product, these cloud vendors not only gain a far richer virtual infrastructure platform at no cost, they also get instant native support for Windows guests in addition to the Linux guests they offer today.  This will also make it easier for Linux OS vendors who currently include Xen in their products to move to the full XenServer, giving their customers far more value and focusing their development efforts on adding differentiated services on top of the virtualization platform.

“The Xen virtualization engine has been a key component of SoftLayer’s cloud computing strategy, providing the performance scalability and track record we have needed to achieve our vision of using virtualization to transform the datacenter,” said Nathan Day, CTO, SoftLayer.  “With this move today by Citrix, we can gain even further leverage using the full power of XenServer in our next-generation cloud computing platform with more efficiency and richer functionality than ever before.  XenServer, as part of the Citrix Cloud Center (C3) platform, is really leading the way in the emerging cloud segment by helping its customers and partners navigate the rapidly-evolving technology.”

As a result of this move, XenServer will also now be included as a core feature of Citrix® XenApp™, the company’s flagship application virtualization product line.  Adding XenServer as the base platform under XenApp increases flexibility and helps customers consolidate the number of physical servers in production with virtually no overhead.  More than one million servers in enterprise datacenters today are running XenApp.

Step up to Advanced Virtualization Management When Ready
Customers who wish to add more advanced virtualization management capabilities in the future will also be able to purchase  Citrix Essentials™ for XenServer, a new product line that includes a rich set of capabilities specifically optimized for the XenServer environment (please see today’s separate announcement).  These optional features – including lab automation, dynamic provisioning, workflow orchestration, high availability and seamless integration with leading storage systems – will be directly visible from the XenCenter™ console in grayed-out mode, making it easy for XenServer administrators to understand the additional capabilities available to them for additional purchase should their needs change over time.  As Citrix adds new enhancements to the Citrix Essentials product line, all active XenServer users will be notified of these new capabilities automatically through their XenCenter management console.

Availability
The new free Citrix XenServer release will be available for download from the Citrix website and other download portals by the end of March 2009.  Citrix Essentials for XenServer will be available from Citrix resellers on April 7, 2009.  Customers who would like to experience a preview of the new XenServer release, as well as get a sneak peek into some of the new features in Citrix Essentials, can download a free trial version today at http://www.citrix.com/freexenserver

About Citrix Systems, Inc.
Citrix Systems, Inc. is the global leader and the most trusted name in Application Delivery Infrastructure. More than 215,000 organizations worldwide rely on Citrix to deliver any application to users anywhere with the best performance, highest security and lowest cost. Citrix customers include 100 percent of the Fortune 100 companies and 99 percent of the Fortune Global 500, as well as hundreds of thousands of small businesses and prosumers. Citrix has approximately 8,000 partners in more than 100 countries. Annual revenue in 2008 was $1.6 billion.

For Citrix Investors
This release contains forward-looking statements which are made pursuant to the safe harbor provisions of Section 27A of the Securities Act of 1933 and of Section 21E of the Securities Exchange Act of 1934.  The forward-looking statements in this release do not constitute guarantees of future performance.  Investors are cautioned that statements in this press release, which are not strictly historical statements, involve a number of factors that could cause actual results to differ materially, including risks associated with the uncertainty in the IT spending environment and a downturn in economic conditions generally, revenue growth and recognition of revenue, products, their development and distribution, product demand and pipeline, competitive factors, the Company’s key strategic relationships, acquisitions and related integration risks as well as other risks detailed in the Company’s filings with the Securities and Exchange Commission. Citrix assumes no obligation to update any forward-looking information contained in this press release or with respect to the announcements described herein.