My Tech Visits

During the working day – over lunch usually, and when I have some time to waste I’ll frequent a number of tech related sites so I thought I’d jot them down here for reference.

Packet Pushers

Packet_Pushers_Logo

http://packetpushers.net/

I don’t visit the Packet Pushers website too often, but they are probably my most frequently listened to podcast. There are some informative blog posts on their site and you can also access all of the podcasts there too.

The Register

the_register_2

https://www.theregister.co.uk/

The Register is easily my number one IT news website I visit. It not only has up to date news, but the writers add their own satirical/comical slant on the news, which I really like. Highly recommended.

IPSpace

IP_Space

http://www.ipspace.net/

IPSpace is an networking orientated blog not affiliated to any vendors (for the record) that’s run by CCIE #1354┬áIvan Pepelnjak. On this blog you’ll find excellent articles, webinars, books relating to architectures, real-life solutions, technologies and more.

Packet Life

Packet_Life

http://packetlife.net/

Packet Life is a blog by Jeremy Stretch, an extremely knowledgeable network engineer who enjoys sharing what he’s learned with his readers.

There are some fantastic networking cheat sheets on this site, along with lots of great tech posts, packet capture trace files, software and book recommendations and much, much more. Definitely worth a look.

I.

the_register

Website Resilience in AWS

In February of this year Amazon Web Services suffered a pretty bad outage on it’s S3 (Simple Storage Service) platform, which is used by millions of it’s customers, predominantly for hosting websites and the issues caused many of these sites to go dark.

Now, although to some degree one should expect their hosted content to be unavailable at some point, when hosted externally in the public cloud (they don’t offer 100% availability, derr!), it would appear those impacted decided to skimp on resilience.

Non-resilient Website

The above diagram illustrates a regular website being hosted on AWS. You type in a domain name, a lookup is performed via AWS’s DNS service – Route 53, you’re forwarded on to a Linux or Windows VM running your web server code and your content is passed to the requester via S3 buckets. If you’re popular enough to have comments/feedback etc then this is stored in a back-end RDS database.

Now let’s take S3 buckets, data is replicated within an Availability Zone (which houses more than two data centres), but not across different AZ’s or geographical regions, you can configure this, but must pay for the benefit.

Website_Resilient_Regions
Website Resilience

In this scenario, you mitigate any real possibility of your business critical website going dark, as even if Amazon have S3 issues in an AZ or even a region, the likelihood of two zones going dark would require something pretty spectacular (read: devastating) to occur.

You have DNS resolution occurring using multiple ELBs (Elastic Load Balancers), therefore if one lookup fails you still have a second juicy AZ or region to fall back on and point your requesting users at.

There are a few more bells and whistles to the above diagram, notably a CloudFront distribution to serve cached files to users from geographically closer servers. And also the use of Auto-Scaling groups to automatically scale up and down my web server cluster if demand warrants it.

The recent AWS outage shows us that we all need to think about how important and costly would it be off domain X were to go offline.

I.

website

Powered by WordPress.com.

Up ↑