eRacks Systems Tech Blog
Open Source Experts Since 1999
What’s your dream developer system?
We at eRacks are designing a new model geared specifically toward the developer, and want to hear from you, the customer, about what you would like to see in the system (please leave detailed comments for this blog post!)
We’ve been batting around a few ideas, both software and hardware related, and would like to share them here for your consideration.
1. IDE, Revision Control System and your Operating System of Choice
Our development model would (of course!) come pre-installed with the best in open source development-related software. Do you have a favorite IDE, or do you prefer to simply invoke your text editor, compiler and makefiles directly? Would you like us to install a revision control system such as CVS, Subversion, Mercurial or Git? What’s your operating system of choice? Are you a fan of Linux, FreeBSD, OpenBSD, NetBSD, OpenSolaris, etc.?
2. What Kind of Developer are you?
While there are usually at least some applications common to most developers, a great deal of the software you’d like to be installed will probably depend significantly on the kind of development you do. Are you a kernel developer? If so, we’ll install the kernel source and headers for you. Are you an applications developer? If so, are there any open source libraries you’d like us to pre-install for you? What about you web developers out there? We could, at your option, install a local web and database server for testing purposes, as well as your scripting engine of choice (PHP, Ruby, Python, Perl, etc.) Do you not fit exactly into any of these categories? Have we missed something? Let us know!
3. Hardware
Do you prefer to develop on a laptop, or do you like to do your programming on a desktop machine? What would you think about having the option of two or more monitors to help you spread out your work, configured to your unique specifications (would you like 2 or more individual displays, or 2 or more monitors tied together into a single virtual display?)
Anything we haven’t mentioned that you’d love to see in a development-specific model? Again, just let us know! Be sure to leave us a comment sharing your thoughts.
james September 18th, 2008
Posted In: Development, New products
Recession-Proof Your IT Infrastructure
from The Open Source Newsletter – July 2008
Aside from all the usual green advice, what can a conscientious SysAdmin do to save money during this time of rising energy prices and a challenging economic situation?
Here is eRacks’ top-ten list of recession-proofing strategies:
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- 1 – Update the Linux OSes if they are older than kernel 2.6.21, to take advantage of the ACPI tickless idle. Install PowerTOP (on Intel-based desktops & notebooks) or other similar tools that examine power consumption by application.
- 2 – Basic maintenance: vacuum the vents (from the outside of the chassis, with the computer off). The buildup of dust and dirt prevents airflow. After cleaning, the systems will cool more easily. The vacuum and/or the little bottle of compressed air are your friends. A word of caution though: don’t even think about reversing the vacuum to blow the dust inside the computer case. The household dust inside the vacuum is not a good thing for the computer (or you). In fact, don’t stick the vacuum inside the computer case at all, since vacuums create static electricity which can also damage your system.
- 3 – Re-think your network diagram. Old systems are often wasteful of energy.
- Consider consolidating systems; Own your own virtualization system:
eRacks/SOLO and eRacks/SUITE are capable of running several virtual machines simultaneously.
Your physical host server can be configured with your choice of a virtualization host, including the freely available version of VMWare or Linux-native KVM (Kernel-based Virtual Machine), as well as a large number of possible virtual operating systems and applications, including web, DNS, email, proxy and other infrastructure services.You’ll save power, save money, and also allow for more centralized administration and ease of backup. eRacks will even pre-install the targeted configurations of your choice. Just ask. - Or take advantage of a hosting solution like Libre Hosting. Get full (root) use of your own virtual server fast. This is a great way to test out a new project, minimizing both your financial investment and configuration effort.
- Or use newer low power servers like the eRacks/LITE, eRacks/QUIET, and any of our desktop line. eRacks will happily customize a system for low power usage, with your requirements.
- Consider consolidating systems; Own your own virtualization system:
- 4 – Plan for upgrades. Buy systems that use only industry-standard components (like eRacks!) so that you can upgrade without being tied to a manufacturer and higher prices.
- 5. Plan for efficient scaling. This depends on the most likely way(s) your company/institution would require expansion in the future. An increase in number of users, production, machine power, etc would each create different infrastructure requirements. Planning longer term, could enable growth while minimizing costs. Using hosted virtualized servers could allow for more flexibility in scaling, up and down, – very handy in peak demand time.
- 6. Rethink security and firewalls. Use preventive measures now, rather than costly fixes later. Read summaries of firewall logs to gauge how busy your firewall system is. Consider options like eRacks’ failover redundant firewall:
- 7. Update your sysadmin tools. Make a bootable DVD or USB drive with your favorite sysadmin utilities on it. Save time by setting up system monitoring and detect any issues before they become big problems.
- 8. This one is for the marketing/sales dept: Find clients that are recession-proof. Where are your main profits coming from? Do you have a few clients in markets that are recession-proof? If not how can you attract those clients, now and get on their vendor lists? – Educational institutions like Trilogy Education Services are usually somewhat stable in their purchasing because people tend to return to school in times of a recession.
- 9. Again to the marketing guys: Globalize your products and presentation with the help of SEO services. Keep in mind that a weak dollar may increase your international customers.
- 10. Always wise: Keep notes – keep an internal company wiki. From our experience, this can be a great tool and reference, saving time, effort and money!
Remember, recession isn’t permanent, but can be long. And playing it smart now will help, and quite possibly make all the difference.
britta August 8th, 2008
Posted In: News
Tags: firewall, recession-proof, security
Six Tips for Effective Virtualization Security
A secure environment is absolutely crucial for a virtualization server connected to the Internet. If the host is compromised, all its virtual machines are at risk and their services will be affected, learn more from these important internet safety tips and advice article.
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eRacks virtualization experts have put together a useful list of security considerations for virtualization migration planners. TIP #1. Use an open source virtualizer if possible. Open source software vulnerabilities are documented clearly, are well-known, and fixed quickly. |
| Proprietary-software bugs usually take longer to get fixed, and are even sold on black markets for illicit hacking. In fact, there are documented cases of closed source software companies purchasing security hole information of their own applications. Open source software vulnerabilities have less value on the black market, because of their shorter shelf-life. If you have a dental practice, you may want to check out sites like https://cloud9.software/cloud-9-ortho/ and see if this software can help increase productivity and efficiency. | |
| TIP #2. Use open source guests wherever possible. New drivers for open source applications improve security as well as performance. Open source guests are more cooperative with the host, leaving less room for attack. Windows is inherently less secure, since a – it is closed source and updated less frequently. b – widely used and thus a big target. c – statistically has more severe vulnerabilities than open source OSes which take longer to fix. | |
| TIP #3. Minimize the host footprint, making less surface area available for hackers. A small target is harder to hit than a large one. eRacks typically recommends KVM because of its small footprint, simple design, and ease of use. The virtualization host provides services in the form of ports and packages, which should only include those required by the VMs. An effective security plan should minimize the number of open ports, narrowing the possibilities of illicit entry. |
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 TIP #5. Use an external physical firewall. It is also possible to use a virtualized firewall, running as a guest, but it can only protect the downstream systems, and not the host. A virtualized IP-less bridging firewall is also possible but it is more difficult to implement, and still doesn’t protect the host. The safest solution is an external firewall, such as the eRacks/TWINGUARD, a redundant 1U system, with failover, running a very secure OpenBSD.
You can look for Fortinet if you want to know about the next-generation firewall. |
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| TIP #6. Assess your security level, including regular port scans (Nmap), and OS fingerprinting, keeping track of any changes. A hardened system will not give out versions of running services, otherwise it would be too easy to know exactly where the vulnerabilities lie. eRacks can give you a head start by building, installing, and configuring your system for you. Your physical host server can be configured with your choice of a virtualization host, including the freely available version of VMWare or Linux-native KVM (Kernel-based Virtual Machine), as well as a large number of possible virtual operating systems and applications, including web, DNS, email, proxy and other infrastructure services. | |
| virtualizer | description | complexity | level of open source |
| KVM | built into the kernel, uses the standard Linux scheduler, memory management and other services | simple, non-intrusive, very stable, easy to administrate – KVM hypervisor about 10-12K lines of code (2007) |
released under the GNU GPL free |
| Xen | external hypervisor, supports both paravirtualization and full virtualization, has its own scheduler, memory manager, timer handling, and machine initialization. | specially modified kernel – has 10x more lines of code as KVM => raises the vulnerability level | released under the GNU GPL free |
| VMware | fully virtualizes using software techniques only, very good performance, stability. | very large and complex; more than 10x lines of code of Xen | proprietary, player open (teaser-ware), fees |
britta July 9th, 2008
Posted In: News, security, virtualization
Tags: firewall, News, redundant firewall, security, twinguard, virtualization
How to Avoid Pain and Suffering when Upgrading Desktop-Oriented Linux Distributions
This article is geared toward eRacks customers who have a desktop or laptop system, i.e. a personal workstation. It is not intended to serve as a guide for customers wishing to upgrade a server.
With the above in mind, for those who use Linux on such a machine, your choice of distributions that cater to this niche is growing nicely. You have the “Big Boys” such as Ubuntu, Fedora, Mandriva or OpenSUSE, as well as a host of more specialized distributions, the main focus of most being on user friendliness and “up-to-dateness.” What this usually leads to is a faster upgrade cycle than what you would typically find on a server oriented distro such as Debian (stable), RedHat Enterprise, SuSE Enterprise or CentOS.
I myself have been tracking RedHat (including Fedora) since version 5.0, doing a mix of upgrades and fresh installs. I have also kept up with Ubuntu since 6.04, and have had similar experiences with it. I have found that one way of making regular upgrades easier is to keep a separate /home partition. This way, you have a choice of an upgrade or a fresh install, without losing valuable data.
My experience, and that of many other salty seasoned Linux gurus, is that upgrading from a previous version tends to be a bit messier and usually takes longer to do than a fresh install. This can be true, especially if you use third party repositories, if you install software not maintained by your distro package manager (DEB or RPM) or if you do a lot of tweaking. Doing so may leave you looking at a broken system when the upgrade finishes. For this reason, it is usually more desirable to do a clean installation and install your third party applications afterward.
How then to keep from losing your data? Many system admins would suggest the multiple partition method, which has been used on servers a lot, yet not so much on the desktop. The multiple partition method can have advantages and disadvantages, but since hard drives are so big these days, many of the disadvantages are no longer prevalent.
While most modern desktop distros have a default partitioning scheme that gives you just a swap partition (usually about 2x the amount of RAM, or physical memory) and a large root partition for everything else, most server configurations have multiple partitions for directories like /usr or /var, which can have many advantages. For example: if you wanted to have /usr mounted as read-only to prevent unauthorized system-wide software installs, if you wanted to keep /boot separate for a RAID array or if you wanted to keep /var and /tmp separate to avoid corrupting the core system files; these are all examples of why one might want to make use of multiple partitions. In this case, however, the partitioning must be very carefully planned according to the intended use of the server, what programs need to be installed, how many users will be logging in, etc.
Luckily, there is a happy medium that works well for desktops, and that is to use a swap partition with 2x the amount of RAM, a root partition for your operating system and a very large /home partition for all your data. When you do a fresh install, all you have to do is make sure you don’t format /home, and your data will be safe across installations. If you want to save any system-wide tweaks, you will, of course, also have to backup important configuration files and check them against their replacements, making changes where necessary.
In my case, I have a 120GB hard drive for Linux, which makes use of the following partition scheme:
20GB /
75GB /home
1GB /swap
14GB “other” (at times it has a Gentoo install, other times it has FreeBSD, depends on my mood…)
I have found through experience that this setup works well.
When I do an OS update, such as my recent one to Fedora 9, I usually backup important configuration files to /home, do a fresh install and finally install any third party programs I need.
In the past, when upgrading systems without doing a fresh install, things for me have tended to get rather wonky. However, I have recently tried upgrading Ubuntu, and I must say that the recently improved Upgrade Manager, a graphical front end to the apt-get dist-upgrade functionality, is a nice touch. It allows you to upgrade to the next version of Ubuntu, while still allowing you to run your system so you can go about your business as it downloads and installs all the packages. When it’s done, you simply reboot, and voila, new version! Upgrades on Fedora, by contrast, are still usually done by the tried and true method of booting the install disk and running the upgrade procedure. Fedora does have the capability to do upgrades using the yum package manager, but that functionality isn’t as mature as apt-get dist-upgrade, and thus is not for the faint of heart.
So now, what if you have an existing Linux installation utilizing only a single partition and you want to do a fresh install while keeping your data safe?
Of course, you could just back your data up to a large external hard drive, but not everyone has one at their disposal. In this case, what you could try is resizing your root partition, create a new partition for /home and copy your personal data to it before starting the upgrade. Then, just run through the installation as usual. This is, of course, only if you have enough space to resize. If not, you may still require an external drive, at least temporarily, to copy your data to before starting the installer.
If you want to make use of multiple partitions on a new eRacks system purchase, just ask for it during your order. This way, your system will be ready when the next OS update rolls around!
Matt
Matt June 27th, 2008
Posted In: How-To, Laptop cookbooks, Upgrades
Useful commands for backing up filesystems
Have you ever needed to backup the contents of one or more filesystems to another machine, yet you only had a single hard drive in the machine being backed up and found that you lacked the temporary disk space necessary to create your backup before shuttling it across the network to its final destination?
As an example, when I backup my laptop, I have too many gigabytes of data to realistically store my data on DVD-R’s, and my only option is to create a tarball of the root filesystem and store it on another machine on my network. The problem is that if I try to create a backup of my laptop’s contents, I find that the resulting tarball backup is too large to fit on the hard drive along with all the data.
One solution that I’ve found to this problem is to avoid storing the backup on the source machine altogether. Through stdin and stdout, along with the magic of *NIX pipes, we can stream the data in realtime over to its destination, and only then write it to disk.
Before we begin, it is very important to note that in most situations, you’ll have to boot into another environment and manually mount your partition before proceeding, particularly when dealing with an operating system’s root filesystem. Otherwise, not only will tar choke on certain directories like /proc and /dev, the contents of the disk will also continue to change as the backup is being made, leading to inconsistencies between the data on your filesystem and the data in the backup.
With that in mind, assuming that you have ssh installed and configured correctly on both the source and destination computers, you can create a backup with the following commands (as root):
#cd /path/to/your/mounted/filesystem
#tar -jcvp | ssh username@destination “cat > /path/to/backup.tar.bz2”
If you prefer to use gzip as opposed to bzip2, replace the above tar command with the following:
#tar -zcvp | ssh username@destination “cat > /path/to/backup.tar.gz”
Now, let’s say that you’ve created a new partition and want to restore a previous backup. Again, assuming that ssh is configured properly on the source and the destination machines, and assuming that you’ve mounted your partition, you would recover your backup with the following commands (again, as root):
#cd /path/to/your/mounted/filesystem
#ssh username@destination “cat /path/to/backup.tar.bz2” | tar -jvxp
If the backup is a gzipped archive, then replace the above tar command with the following:
#ssh username@destination “cat /path/to/backup.tar.gz” | tar -zvxp
Note that the user specified by ‘username’ above should have read/write permissions on the directory where the backup is to be stored for this procedure to work.
The astute reader will probably notice the missing -f option, which one usually passes to tar. The reason for this is that it tells tar to write its data to, or read its data from, a file. However, by ommitting it, we tell tar to send its output to stdout, or to receive its data from stdin when reading from an archive, which allows us to make use of pipes. It’s situations like these where the power of *NIX really shines!
james May 28th, 2008
Posted In: Backups
Tags: backup, bzip, bzip2, filesystem, gzip, partition, ssh, zip