Open Source Enables the Cloud

With the fast growth of virtualized data centers, and companies like Google, Amazon and Facebook, it’s easy to forget how much is built on open-source components, aka commodity software.  In a very real way open-source has enabled the huge explosion of commodity hardware, the fast growth of the internet itself, and now the further acceleration through cloud services, cloud infrastructure, and virtualization of data centers.

Your typical internet stack and application now stands on the shoulders of tens of thousands of open source developers and projects.  Let’s look at a few of them. Continue reading “Open Source Enables the Cloud”

Cloud for Burst Capacity

One very strong case for cloud computing is that it can satisfy applications with seasonal traffic patterns.  One way to test the advantages of the cloud is through a hybrid approach.

Cloud infrastructure can be built completely through scripts.  You can spinup specific AMIs or machine images, automatically install and update packages, install your credentials, startup services, and you’re running.

All of these steps can be performed in advance of your need at little cost.  Simply build and test.  When you’re finished, shutdown those instances.  What you walk away with is scripts.  What do we mean?

The power here is that you carry zero costs for that burst capacity until you need it.  You’ve already build the automation scripts, and have them in place.  When your capacity planning warrants it, spinup additional compute power, and watch your internet application scale horizontally.  Once your busy season is over, scale back and disable your usage until you need it again.

8 Questions to ask an AWS Expert

via GIPHY

If you’re headhunting a cloud computing expert, specifically someone who knows Amazon Web Services (AWS) and EC2, you’ll want to have a battery of questions to ask them to assess their knowledge.  As with any technical interview focus on concepts and big picture.  As the 37Signals folks like to say “hire for attitude, train for skill”.  Absolutely!





New: Top questions for hiring a serverless lambda expert

Also new: Top questions to ask on a devops expert interview

And: How to hire a developer that doesn’t suck

If you want more general info about Amazon Web Services, read our Intro to EC2 Deployments.

    1. Explain Elastic Block Storage?  What type of performance can you expect?  How do you back it up?  How do you improve performance?

    EBS is a virtualized SAN or storage area network.  That means it is RAID storage to start with so it’s redundant and fault tolerant.  If disks die in that RAID you don’t lose data.  Great!  It is also virtualized, so you can provision and allocate storage, and attach it to your server with various API calls.  No calling the storage expert and asking him or her to run specialized commands from the hardware vendor.

    Need help? Check out my pricing page or email [email protected]

    Performance on EBS can exhibit variability.  That is it can go above the SLA performance level, then drop below it.  The SLA provides you with an average disk I/O rate you can expect.  This can frustrate some folks especially performance experts who expect reliable and consistent disk throughput on a server.  Traditional physically hosted servers behave that way.  Virtual AWS instances do not.

    Related: Is Amazon too big to fail?

    Backup EBS volumes by using the snapshot facility via API call or via a GUI interface like elasticfox.

    Improve performance by using Linux software raid and striping across four volumes.

    2. What is S3?  What is it used for? Should encryption be used?

    S3 stands for Simple Storage Service.  You can think of it like ftp storage, where you can move files to and from there, but not mount it like a filesystem.  AWS automatically puts your snapshots there, as well as AMIs there.  Encryption should be considered for sensitive data, as S3 is a proprietary technology developed by Amazon themselves, and as yet unproven vis-a-vis a security standpoint.

    Also: How careful notes are helping me work better with clients

    3. What is an AMI?  How do I build one?

    AMI stands for Amazon Machine Image.  It is effectively a snapshot of the root filesystem.  Commodity hardware servers have a bios that points the the master boot record of the first block on a disk.  A disk image though can sit anywhere physically on a disk, so Linux can boot from an arbitrary location on the EBS storage network.

    Need an AWS expert? Email me for a quote hullsean @ gmail.com

    Build a new AMI by first spinning up and instance from a trusted AMI.  Then adding packages and components as required.  Be wary of putting sensitive data onto an AMI.  For instance your access credentials should be added to an instance after spinup.  With a database, mount an outside volume that holds your MySQL data after spinup as well.

    4. Can I vertically scale an Amazon instance? How?

    Yes.  This is an incredible feature of AWS and cloud virtualization.  Spinup a new larger instance than the one you are currently running.  Pause that instance and detach the root ebs volume from this server and discard.  Then stop your live instance, detach its root volume.  Note the unique device ID and attach that root volume to your new server.   And the start it again.  Voila you have scaled vertically in-place!!

    5. What is auto-scaling? How does it work?

    Autoscaling is a feature of AWS which allows you to configure and automatically provision and spinup new instances without the need for your intervention.  You do this by setting thresholds and metrics to monitor.  When those thresholds are crossed a new instance of your choosing will be spun up, configured, and rolled into the load balancer pool.  Voila you’ve scaled horizontally without any operator intervention!

    Also: Are we fast approaching cloud-mageddon?

    With MySQL databases autoscaling can get a little dicey, so we wrote a guide to autoscaling MySQL on amazon EC2.

    6. What automation tools can I use to spinup servers?

    The most obvious way is to roll-your-own scripts, and use the AWS API tools.  Such scripts could be written in bash, python or another language or your choice.  Next option is to use a configuration management and provisioning tool like puppet or better it’s successor Opscode Chef. Ansible is also an excellent option because it doesn’t require an agent, and can run your shell scripts as-is.  You might also look towards CloudFormation or Terraform. The resulting code captures your entire infrastructure, can be checked into your git repository & version controlled. You can even unit test this way! 

    7. What is configuration management?  Why would I want to use it with cloud provisioning of resources?

    Configuration management has been around for a long time in web operations and systems administration.  Yet the cultural popularity of it has been limited.  Most systems administrators configure machines as software was developed before version control – that is manually making changes on servers.  Each server can then and usually is slightly different.  Troubleshooting though is straightforward as you login to the box and operate on it directly.  Configuration management brings a large automation tool into the picture, managing servers like strings of a puppet.  This forces standardization, best practices, and reproducibility as all configs are versioned and managed.  It also introduces a new way of working which is the biggest hurdle to its adoption.

    Read: When hosting data on Amazon turns bloodsport

    Enter the cloud, and configuration management becomes even more critical.  That’s because virtual servers such as amazons EC2 instances are much less reliable than physical ones.  You absolutely need a mechanism to rebuild them as-is at any moment.  This pushes best practices like automation, reproducibility and disaster recovery into center stage.

    While on the subject of configuration management take a quick peek at hiring a devops guide.

    8. Explain how you would simulate perimeter security using Amazon Web Services model?

    Traditional perimeter security that we’re already familiar with using firewalls and so forth is not supported in the Amazon EC2 world.  AWS supports security groups.  One can create a security group for a jump box with ssh access – only port 22 open.  From there a webserver group and database group are created.  The webserver group allows 80 and 443 from the world, but port 22 *only* from the jump box group.  Further the database group allows port 3306 from the webserver group and port 22 from the jump box group.  Add any machines to the webserver group and they can all hit the database.  No one from the world can, and no one can directly ssh to any of your boxes.

    The more full featured way to go is VPC. That’s Amazon’s acronym for virtual private cloud. You can create virtual networks both private & public, with subnets etc all within VPCs. You then spinup servers & resources inside those virtual networks. VPCs can be control with security groups or the more powerful but messy access control lists.

    Also: A history lesson for cloud detractors – January 2012

    Want to further lock this configuration down?  Only allow ssh access from specific IP addresses on your network, or allow just your subnet.

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The New Commodity Hardware Craze aka Cloud Computing

Does anyone remember 15 years ago when the dot-com boom was just starting?  A lot of companies were running on Sun.  Sun was the best hardware you could buy for the price.  It was reliable and a lot of engineers had experience with the operating system, SunOS a flavor of Unix.

Yet suddenly companies were switching to cheap crappy hardware.  The stuff failed more often, had lower quality control, and cheaper and slower buses.  Despite all of that, cutting edge firms and startups were moving to commodity hardware in droves.  Why was it so? Continue reading “The New Commodity Hardware Craze aka Cloud Computing”

7 Ways to Troubleshoot MySQL

MySQL databases are great work horses of the internet.  They back tons of modern websites, from blogs and checkout carts, to huge sites like Facebook.  But these technologies don’t run themselves.  When you’re faced with a system that is slowing down, you’ll need the right tools to diagnose and troubleshoot the problem.  MySQL has a huge community following and that means scores of great tools for your toolbox. Here are 7 ways to troubleshoot MySQL. Continue reading “7 Ways to Troubleshoot MySQL”

5 Ways to Avoid EC2 Outages

1. Backup outside of the Cloud

Some of the high profile companies affected by Amazon’s April 2011 outage could have recovered had they kept a backup of their entire site outside of the cloud.  With any hosting provider, managed traditional data center or cloud provider, alternate backups are always a good idea.  A MySQL logical backup and/or incremental backup can be copied regularly offsite or to an alternate cloud provider.  That’s real insurance! Continue reading “5 Ways to Avoid EC2 Outages”

Review – Test Driven Infrastructure with Chef – Stephen Nelson-Smith

In search of a good book on Chef itself, I picked up this new title on O’Reilly.  It’s one of their new format books, small in size, only 75 pages.

There was some very good material in this book.  Mr. Nelson-Smith’s writing style is good, readable, and informative.  The discussion of risks of infrastructure as code was instructive.  With the advent of APIs to build out virtual data centers, the idea of automating every aspect of systems administration, and building infrastructure itself as code is a new one.  So an honest discussion of the risks of such an approach is bold and much needed.  I also liked the introduction to Chef itself, and the discussion of installation.

Chef isn’t really the main focus of this book, unfortunately.  The book spends a lot of time introducing us to Agile Development, and specifically test driven development.  While these are lofty goals, and the first time I’ve seen treatment of the topic in relation to provisioning cloud infrastructure, I did feel too much time was spent on that.  Continue reading “Review – Test Driven Infrastructure with Chef – Stephen Nelson-Smith”

Amazon Web Services – What is it and why is it important?

Amazon Web Services is a division of Amazon the bookseller, but this part of the business is devoted solely to infrastructure and internet servers.  These are the building blocks of data centers, the workhorses of the internet.  AWS’s offering of Cloud Computing solutions allows a business to setup or “spinup” in the jargon of cloud computing, new compute resources at will.  Need a small single cpu 32bit ubuntu server with two 20G disks attached?  One command and 30 seconds away, and you can have that!

As we discussed previously, Infrastructure Provisioning has evolved dramatically over the past fifteen years from something took time and cost a lot, to a fast automatic process that it is today with cloud computing.  This has also brought with it a dramatic culture shift in the way that systems administration is being done, from a fairly manual process of physical machines, and software configuration, one that took weeks to setup new services, to a scriptable and automateable process that can then take seconds.

This new realm of cloud computing infrastructure and provisioning is called Infrastructure as a Service or IaaS, and Amazon Web Services is one of the largest providers of such compute resources.  They’re not the only ones of course.  Others include:

  • Rackspace Cloud
  • Joyent
  • GoGrid
  • Terremark
  • 3Tera
  • IBM
  • Microsoft
  • Enomaly
  • AT&T

Cloud Computing is still in it’s infancy, but is growing quickly.   Amazon themselves had a major data center outage in April that we discussed in detail. It sent some hot internet startups into a tailspin!

More discussion of Amazon Web Services on Quora – Sean Hull

IOPs – What is it and why is it important?

IOPs are an attempt to standardize comparison of disk speeds across different environments.  When you turn on a computer, everything must be read from disk, but thereafter things are kept in memory.  However applications typically read and write to disk frequently.  When you move to enterprise class applications, especially relational databases, a lot of disk I/O is happening so performance of disk resources is crucial.

For a basic single SATA drive that you might have in server or laptop, you can typically get 30-40 IOPs from it.  These numbers vary if you are talking about random versus sequential reads or writes.  Picture the needle on a vinyl record.  It moves quicker around the center, and slower around the outside.  That’s what’s happening the the magnetic needle inside your harddrive too.

In Amazon EC2 environment, there is a lot of variability in performance from EBS.  You can stripe across four separate EBS volumes which will be on four different locations on the underlying RAID array and you’ll get a big boost in disk I/O.  Also disk performance will vary from an m1.small, m1.large and m1.xlarge instance type, with the latter getting the lions share of network bandwidth, so better disk I/O performance.  But in the end your best EBS performance will be in the range of 500-1000 IOPs.  That’s not huge by physical hardware standards, so an extremely disk intensive application will probably not perform well in the Amazon cloud.

Still the economic pressures and infrastructure and business flexibility continue to push cloud computing adoption, so expect the trend to continue.

Quora discussion – What are IOPs and why are they important?