Containers 101: What You Need to Know

Containers are the future of web development, in large part thanks to Docker's explosive growth. According to DataDog, 15 percent of hosts run Docker, which is significantly up from the 6 percent of hosts running it at this point in 2015. LinkedIn has also seen a 160 percent increase in profile references to Docker in just the past year alone, indicating Docker has become a much bigger priority for IT professionals looking for work. With this technology primed to continue its exponential growth in the coming years, here's a Q&A rundown of the basics: consider it Containers 101.

What are containers, exactly? And why are they so rapidly grabbing developer market share from virtual machines?

In order to better understand containers, it's helpful to consider them in contrast to virtual machines.

A virtual machine (VM) is an emulation of an entire operating system managed by a hypervisor. A VM may be run over the top of another OS or directly off the hardware. In either case, one VM can and usually will be run alongside other VMs, all of which are allocated their own set static space and resources by the hypervisor, with each VM acting as its own independent computer.

A container is a self-contained (it's right there in the name) execution environment with its own isolated network resources. At a quick glance, a container may appear very similar to a VM. The key difference is that a container does not emulate a separate OS. Containers instead create separate, independent user spaces that have their own bins and libs, but that share the host operating system's kernel with all other containers running on a machine. This being the case, containers do not need to be assigned their own set amount of RAM and other resources; they simply make use of whatever they need while they're running.

In short: a virtual machine virtualizes the hardware, while a container virtualizes the OS.

This means containers are significantly more lightweight than VMs. They can be spun up in seconds instead of minutes and you can run as many as 8x as many of them on a single machine. Since the OS has been abstracted away, containers can be easily moved from one machine to another. They're developer- and DevOps-friendly, and offer improved infrastructure and cost efficiency.

What is contained in a container?
A container is made up of container images that bundle up the code and all its dependencies. One of these container images will be the app itself. The other images will be the libraries and binaries needed to run that app. All the images that make up the container are then turned into an image template that can be reused across multiple hosts.

It may sound like a lot of effort to add all the necessary individual images to a container, but all your images are stored and run out of a registry. If your application needs Ubuntu, PHP 7.0, and Apache to run then you'll reference these in your config file and your container manager will pull them from this registry (assuming they're there).

Where does Docker come into all of this?
Containers are nothing new - they've been part of Linux since the creation of chroot in 1982 - but to run them, you need a container manager like the one referenced above. Docker is by far the most popular of these (it's nearly synonymous with containers at this point) and has been at the forefront of the rapid surge in container usage. What sets it apart?

The Docker Hub: This hub is the registry where your various images are privately stored. It's also a rich ecosystem of public images built by other Docker users that you can pull down and use for your own projects. Why do all the grunt work when there are other people out there who have already done it?

Portability: Containers are already portable just by the nature of their design, but Docker guarantees the environment will be exactly the same when moving an image from one Docker host to another so you can build once and run anywhere.

Easy Version History and Rollbacks: Docker containers are read-only post-creation. That doesn't mean you can't make changes. What it means is that any changes are used to create new images whenever you run the "docker commit" command. These new images become new containers that you run just like the original. If an alteration leads to problems in a new image, then you can simply go back to the previous one.

Docker is open source and its technology is the basis of the Open Containers Initiative, which is a Linux Foundation initiative focused on creating "industry standards around container formats and runtime." Google, Amazon, Microsoft and other industry leaders are also part of the OCI.

Are containers available only on Linux?

Until very recently the answer was yes, but Microsoft added container support to Windows Server 2016. This can be managed using Docker for Windows.

Will containers replace virtual machines?

Though containers will absolutely continue to rise in popularity, it's incredibly unlikely they'll replace VMs. Stateful application roles and legacy apps that cannot be refactored will continue to run on VMs. More likely the two will be used in concert with each other, each being put to use where most appropriate. Occasionally, containers might even be run within virtual machines, warping the space time continuum and confusing partisans of both approaches. We truly live in the future.

There are particular concerns about containers and security, as the varied images provide more points of entry for attackers and a container's direct access to the OS kernel creates a larger surface area for attack than would be found in a hypervisor-controlled virtual machine. Automation, as usual, is the key to ensuring solid security.

Download Show Prospectus ▸ Here

DevOps at Cloud Expo taking place October 31 - November 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA, will feature technical sessions from a rock star conference faculty and the leading industry players in the world.

Must Watch Video: Recap of @DevOpsSummit New York Javits Center

The widespread success of cloud computing is driving the DevOps revolution in enterprise IT. Now as never before, development teams must communicate and collaborate in a dynamic, 24/7/365 environment. There is no time to wait for long development cycles that produce software that is obsolete at launch. DevOps may be disruptive, but it is essential.

Nutanix DevOps Booth at @DevOpsSummit New York Javits Center

DevOps at Cloud Expo will expand the DevOps community, enable a wide sharing of knowledge, and educate delegates and technology providers alike. Recent research has shown that DevOps dramatically reduces development time, the amount of enterprise IT professionals put out fires, and support time generally. Time spent on infrastructure development is significantly increased, and DevOps practitioners report more software releases and higher quality. Sponsors of DevOps at Cloud Expo will benefit from unmatched branding, profile building and lead generation opportunities through:

• Featured on-site presentation and ongoing on-demand webcast exposure to a captive audience of industry decision-makers.
• Showcase exhibition during our new extended dedicated expo hours
• Breakout Session Priority scheduling for Sponsors that have been guaranteed a 35 minute technical session
• Online advertising in SYS-CON's i-Technology Publications
• Capitalize on our Comprehensive Marketing efforts leading up to the show with print mailings, e-newsletters and extensive online media coverage.
• Unprecedented PR Coverage: Editorial Coverage on DevOps Journal
• Tweetup to over 75,000 plus followers
• Press releases sent on major wire services to over 500 industry analysts.

For more information on sponsorship, exhibit, and keynote opportunities, contact Carmen Gonzalez by email at events (at) sys-con.com, or by phone 201 802-3021.

Most Popular Video: Sheng Liang's Containers Talk

@DevOpsSummit at Cloud Expo taking place October 31 - November 2, 2017, Santa Clara Convention Center, CA, and is co-located with the 21st International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world.

@DevOpsSummit 2017 Silicon Valley
(October 31 - November 2, 2017, Santa Clara Convention Center, CA)

@DevOpsSummit 2018 New York 
(June 12-14, 2018, Javits Center, Manhattan)

With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend 21st Cloud Expo, October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.

Track 1. Enterprise Cloud | Cloud-Native
Track 2. Big Data | Analytics
Track 3. Internet of Things | IIoT | Smart Cities
Track 4. DevOps | Digital Transformation (DX)
Track 5. APIs | Cloud Security | Mobility
Track 6. AI | ML | DL | Cognitive
Track 7. Containers | Microservices | Serverless
Track 8. FinTech | InsurTech | Token Economy

Speaking Opportunities

The upcoming 21st International @CloudExpo | @ThingsExpo, October 31 - November 2, 2017, Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY announces that its Call For Papers for speaking opportunities is open. Themes and topics to be discussed include:

• Agile
• API management
• APM
• Application delivery
• Cloud development
• Configuration automation
• Containers
• Continuous delivery
• Continuous integration
• Continuous testing
• DevOps anti-patterns
• DevOps for legacy systems
• DevOps skills and training
• DevOps system architecture
• Docker
• Enterprise DevOps
• Identity and access
• IT orchestration
• Kubernetes
• Load testing
• Microservices
• Mobile DevOps
• Monitoring
• Network automation
• Quality assurance
• Release automation
• Serverless
• Scrum
• Service virtualization
• Teaming
• Test automation
• WebOps, CloudOps, ChatOps, NoOps

Submit your speaking proposal today! ▸ Here

Cloud Expo | @ThingsExpo 2017 Silicon Valley
(October 31 - November 2, 2017, Santa Clara Convention Center, CA)

Cloud Expo | @ThingsExpo 2018 New York 
(June 12-14, 2018, Javits Center, Manhattan)

Download Show Prospectus ▸ Here

Every Global 2000 enterprise in the world is now integrating cloud computing in some form into its IT development and operations. Midsize and small businesses are also migrating to the cloud in increasing numbers.  

Companies are each developing their unique mix of cloud technologies and services, forming multi-cloud and hybrid cloud architectures and deployments across all major industries. Cloud-driven thinking has become the norm in financial services, manufacturing, telco, healthcare, transportation, energy, media, entertainment, retail and other consumer industries, and the public sector.

Cloud Expo is the single show where technology buyers and vendors can meet to experience and discus cloud computing and all that it entails. Sponsors of Cloud Expo will benefit from unmatched branding, profile building and lead generation opportunities through:

• Featured on-site presentation and ongoing on-demand webcast exposure to a captive audience of industry decision-makers.
• Showcase exhibition during our new extended dedicated expo hours
• Breakout Session Priority scheduling for Sponsors that have been guaranteed a 35-minute technical session
• Online advertising in SYS-CON's i-Technology Publications
• Capitalize on our Comprehensive Marketing efforts leading up to the show with print mailings, e-newsletters and extensive online media coverage.
• Unprecedented PR Coverage: Editorial Coverage on Cloud Computing Journal.
  
• Tweetup to over 75,000 plus followers
• Press releases sent on major wire services to over 500 industry analysts.

For more information on sponsorship, exhibit, and keynote opportunities, contact Carmen Gonzalez by email at events (at) sys-con.com, or by phone 201 802-3021.

The World's Largest "Cloud Digital Transformation" Event

@CloudExpo | @ThingsExpo 2017 Silicon Valley
(Oct. 31 - Nov. 2, 2017, Santa Clara Convention Center, CA)

@CloudExpo | @ThingsExpo 2018 New York 
(June 12-14, 2018, Javits Center, Manhattan)

Full Conference Registration Gold Pass and Exhibit Hall ▸ Here

Register For @CloudExpo ▸ Here via EventBrite

Register For @ThingsExpo ▸ Here via EventBrite

Register For @DevOpsSummit ▸ Here via EventBrite

Sponsorship Opportunities

Sponsors of Cloud Expo | @ThingsExpo will benefit from unmatched branding, profile building and lead generation opportunities through:

• Featured on-site presentation and ongoing on-demand webcast exposure to a captive audience of industry decision-makers
• Showcase exhibition during our new extended dedicated expo hours
• Breakout Session Priority scheduling for Sponsors that have been guaranteed a 35 minute technical session
• Online targeted advertising in SYS-CON's i-Technology Publications
• Capitalize on our Comprehensive Marketing efforts leading up to the show with print mailings, e-newsletters and extensive online media coverage
• Unprecedented Marketing Coverage: Editorial Coverage on ITweetup to over 100,000 plus followers, press releases sent on major wire services to over 500 industry analysts

For more information on sponsorship, exhibit, and keynote opportunities, contact Carmen Gonzalez (@GonzalezCarmen) today by email at events (at) sys-con.com, or by phone 201 802-3021.

Secrets of Sponsors and Exhibitors ▸ Here
Secrets of Cloud Expo Speakers ▸ Here

All major researchers estimate there will be tens of billions devices - computers, smartphones, tablets, and sensors - connected to the Internet by 2020. This number will continue to grow at a rapid pace for the next several decades.

With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend @CloudExpo | @ThingsExpo, October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-4, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.

Delegates to Cloud Expo | @ThingsExpo will be able to attend 8 simultaneous, information-packed education tracks.

There are over 120 breakout sessions in all, with Keynotes, General Sessions, and Power Panels adding to three days of incredibly rich presentations and content.

Join Cloud Expo | @ThingsExpo conference chair Roger Strukhoff (@IoT2040), October 31 - November 2, 2017, Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, for three days of intense Enterprise Cloud and 'Digital Transformation' discussion and focus, including Big Data's indispensable role in IoT, Smart Grids and (IIoT) Industrial Internet of Things, Wearables and Consumer IoT, as well as (new) Digital Transformation in Vertical Markets.

Financial Technology - or FinTech - Is Now Part of the @CloudExpo Program!

Accordingly, attendees at the upcoming 21st Cloud Expo | @ThingsExpo October 31 - November 2, 2017, Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, will find fresh new content in a new track called FinTech, which will incorporate machine learning, artificial intelligence, deep learning, and blockchain into one track.

Financial enterprises in New York City, London, Singapore, and other world financial capitals are embracing a new generation of smart, automated FinTech that eliminates many cumbersome, slow, and expensive intermediate processes from their businesses.

FinTech brings efficiency as well as the ability to deliver new services and a much improved customer experience throughout the global financial services industry. FinTech is a natural fit with cloud computing, as new services are quickly developed, deployed, and scaled on public, private, and hybrid clouds.

More than US$20 billion in venture capital is being invested in FinTech this year. @CloudExpo is pleased to bring you the latest FinTech developments as an integral part of our program, starting at the 21st International Cloud Expo October 31 - November 2, 2017 in Silicon Valley, and June 12-14, 2018, in New York City.

@CloudExpo is accepting submissions for this new track, so please visit www.CloudComputingExpo.com for the latest information.

About SYS-CON Media & Events

SYS-CON Media (www.sys-con.com) has since 1994 been connecting technology companies and customers through a comprehensive content stream - featuring over forty focused subject areas, from Cloud Computing to Web Security - interwoven with market-leading full-scale conferences produced by SYS-CON Events. The company's internationally recognized brands include among others Cloud Expo® (@CloudExpo), Big Data Expo® (@BigDataExpo), DevOps Summit (@DevOpsSummit), @ThingsExpo® (@ThingsExpo), Containers Expo (@ContainersExpo) and Microservices Expo (@MicroservicesE).

Cloud Expo®, Big Data Expo® and @ThingsExpo® are registered trademarks of Cloud Expo, Inc., a SYS-CON Events company.