server
There are 17 entries for the tag server
Service virtualization is the opposite of – and complementary implementation to – server virtualization. One of the biggest challenges with any implementation of elastic scalability as it relates to virtualization and cloud computing is managing that scalability at run-time and at design (configuration) time. The goal is to transparently scale out some service – network or application – in such a way as to eliminate the operational disruption often associated with scaling up (and down) efforts. Service virtualization allows virtually any service to be transparently scaled out with no negative impact to the service and,...
Infrastructure can be a black box only if its knobs and buttons are accessible I spent hours at Interop yesterday listening to folks talk about “infrastructure.” It’s a hot topic, to be sure, especially as it relates to cloud computing. After all, it’s a keyword in “Infrastructure as a Service.” The problem is that when most of people say “infrastructure” it appears what they really mean is “server” and that just isn’t accurate. If you haven’t been a data center lately there is a whole lot of other “stuff” that falls under the infrastructure moniker in a...
The wrong load balancing algorithm can be detrimental to the performance and scalability of your web applications. When you’re mixing and matching virtual or physical servers you need to take care with how you configure your Load balancer – and that includes cloud-based load balancing services. Load balancers do not at this time, unsurprisingly, magically choose the right algorithm for distributing requests for a given environment. One of the nice things about a load balancing solution that comes replete with application-specific templates is that all the work required to determine the optimal configuration for the load balancer and...
load balancing intermediaries have long used the terms “virtual server” and “virtual IP address”. With the widespread adoption of virtualization these terms have become even more confusing to the uninitiated. Here’s how load balancing and application delivery use the terminology.
I often find it easiest to explain the difference between a “virtual server” and a “virtual IP address (VIP)” by walking through the flow of traffic as it is received from the client.
When a client queries for “www.yourcompany.com” they get an IP address, of course. In many cases if the site is served by a load balancer or...
Cloud computing management functionality and standards are right now laser-focused on virtual machines, and most APIs include the ability to stop,start,launch,etc…at that level of the infrastructure. This is because the application is still insulated by its virtualized environment. The “depth” of management and standards efforts today stops at the hard shell of the virtualization layer and leaves the soft, chewy application center alone. This means nothing is really all that different for developers. But it could, and some might argue should, be different. The development of a web-application for a cloud computing environment today is really...
Are you monitoring the network, servers, stack, or the application? The answer may mean the difference between your application being available or not. One of the biggest problems with moving away from simple load balancing to application delivery is that network teams don’t often get the memo and the application teams don’t have a good understanding of what load balancers can do so they can’t even offer suggestions regarding how to architect a better solution to availability. That means neither team really understands the role of health monitoring in maintaining availability for applications. What should happen...
If they can take down Twitter via DNS, they can take your site, too.
Everyone is talking about the DoS (Denial of Service) attack on Twitter but most of them are missing what really happened. We’re so used to defending against HTTP-based DoS attacks that we’ve missed that it’s much easier to DoS a site based on the most critical piece of infrastructure on the Internet: DNS.
If you really wanted to take out a site like Twitter or Facebook using an HTTP-based DoS it would take a whole lot of serious traffic because those sites are designed and architected...
Notice that isn’t a question, it’s a statement of fact Twitter is having a bad month. After it was blamed, albeit incorrectly, for a breach leading to the disclosure of both personal and corporate information via Google’s GMail and Apps, its apparent willingness to allow anyone and everyone access to a .htaccess file ostensibly protecting search.twitter.com made the rounds via, ironically, Twitter. This vulnerability at first glance appears fairly innocuous, until you realize just how much information can be placed in an .htaccess file that could have been exposed by this technical configuration faux...
Apparently if you’re attending the USENIX Security conference (August 12-14, 2009, in Montreal, Canada) you can participate in the Security Grand Challenge. What is that, you ask? Here’s how the organizers describe it: The concept is very simple. The participant teams will have to use their science and technical skill to create an environment where a server can function with integrity and minimum required service levels even when under attack. On the day of the competition, each participant team will receive a virtualized server, with a number of services. The services might...
As a general rule, we spend far more time worrying about external appearances than we do internal. We are more concerned with our external web applications and how they look - and perform - than we are likely to regarding our intranet or internal only applications. This blog post was interesting in that rather than encouraging folks to optimize web sites and improve end-user response time for web applications for the sake of the user experience, it focused on the relationship between page load time and impact on Google AdWords quality scores. Which is a bit different than...
Cloud computing promises customers the ability to deliver scalable applications on-demand without the overhead of a massive data center. The visibility - and flexibility as well as control - you have into and over the cloud computing environment depends on whether the provider you select offers an opaque or a transparent cloud computing environment.
OPAQUE CLOUD COMPUTING MODEL
In an opaque cloud computing model all details are hidden from the organization. The hardware and software infrastructure details are not necessarily known or controlled by the organization but are completely managed by the cloud computing provider. This allows for a completely...
I'm going to give you an engine low to the ground. An extra-big oil pan that'll cut the wind underneath you. That'll give you more horsepower. I'll give you a fuel line that'll hold an extra gallon of gas. I'll shave half an inch off you and shape you like a bullet. When I get you primed, painted and weighed... ...
Keynote, well known for its application performance testing and monitoring services, just announced a new version of its KITE (Keynote Internet Testing Environment) that is now capable of testing Web 2.0 sites that make use of AJAX, Flash, and other "hidden" methods of obtaining content. Announcement of KITE 2 Performance testing dynamic and HTML websites is now a fairly straightforward process, however the rise of Web 2.0 sites that don’t rely on clicking to reveal another new page have been almost impossible to test. However Keynote has now developed a scripted system that allows you to...
CNet is reporting that Google is ditching XML for a faster, more compact alternative known as ProtocolBuffers. I'm going to type this post really fast before Don finds out and starts laughing at me because he's always had this thing against XML, claiming it was too bloated and slow. Apparently Google, the 800-pound gorilla, is on Don's side of this argument, as it just blogged about its newest creation, ProtocolBuffers. From CNet's Blog PostGoogle thought of using XML as a lingua franca to send messages between its different servers. But XML can be complicated to work with...
Not all DoS (Denial of Service) attacks are the same. While the end result is to consume as much - hopefully all - of a server or site's resources such that legitimate users are denied service (hence the name) there is a subtle difference in how these attacks are perpetrated that makes one easier to stop than the other. SYN Flood A Layer 4 DoS attack is often referred to as a SYN flood. It works at the transport protocol (TCP) layer. A TCP connection is established in what is known as a 3-way handshake. The client...
I read a very nice blog post yesterday discussing some of the traditional pros and cons of load-balancing configurations. The author comes to the conclusion that if you can use direct server return, you should. I agree with the author's list of pros and cons; DSR is the least intrusive method of deploying a load-balancer in terms of network configuration. But there are quite a few disadvantages missing from the author's list. Author's List of Disadvantages of DSR The disadvantages of Direct Routing are: Backend server...
Bob owns a widget shop. Now this widget shop is not your ordinary widget shop, because the widgets are made from Swarovski crystal. Very expensive stuff. Bob is aware that losing any number of his widgets would be financially devastating, and the negative press he'd receive would darken his shop's reputation. So he's invested in a very modern physical security system that utilizes electronic locks on all the doors, and includes all the newest laser motion detection technology. It's further connected to a monitoring service just in case, so he'll know if security has been breached and can...
