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6/12/2014
10:46 AM
Charles Babcock
Charles Babcock
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What Docker Means For VMware, Cloud

Docker containers, backed by an unlikely group of allies, are suddenly the talk of the cloud community. What do containers represent in terms of IT's existing investment in VMware?

Containers emerged at the DockerCon event in San Francisco this week as a technology that is backed by a surprisingly broad spectrum of users, including Google, which says its search engine and all other applications run in containers.

Docker is a particular format for Linux containers that caught on with developers since its inception 15 months ago. Both Amazon Web Services and Microsoft are moving quickly to make Docker containers welcome guests on their respective cloud hosts.

Containers, sometimes described as lightweight virtualization, promise to move software around more easily and level the playing field between clouds. Does that mean IT should abandon its adoption of virtual machines and replace them with containers? What do containers represent in terms of IT's existing investment in VMware and other hypervisor-based management?

One way to answer the question is to look at one of the clearest predecessors to Docker that casts light on what it means. Docker has nothing to do with hypervisors and little to do with the first containerized operating system, Solaris. Rather, it more closely resembles the simple Red Hat Package Manager or RPM. Because open source code was frequently modified, Red Hat early on standardized how discrete modules of code could be packaged to assign them dates of issuance and version numbers so that a package manager system could check for compatibility with other modules and assemble thousands of modules into an operating system (Linux). The importance of RPM is not in the technology -- which is fairly simple -- but in the agreement it enforces among Linux developers to work together in a standard way. Docker does something similar, only for complex applications and on a much larger scale.

[Want to learn more about containers in the cloud? See Red Hat Linux Containers: Not Just Recycled Ideas.]

In the future, containers are expected to be nested. A software component that makes up a layer in one container might be called by another in a remote location. An update to the same layer might be passed on to any other containers that use the same component.

Ben Golub, CEO of Docker Inc., the firm that sponsors the Docker project, likes to draw an analogy with a shipping container: Docker makes it possible to move software around and handle it in a predictable way. But "shipping" falls short of all that Docker enables on the operational front.

Docker creates a sandboxed runtime on the computer on which it lands. It occupies a defined memory space and has access only to specified resources. A container sets up networking for an application in a standard way and carries as discrete layers all the related software that it needs. This tweet from Red Hat Dan came out of the second day of the conference: "A container is like Vegas, what happens in a container stays in that container."

The one exception is that the application in the container must rely on its new host to provide the operating system, which the host already has. A restriction is that the number of the Linux kernel that the application moved from must match the number that it is moving too, a relatively simple standard to meet in exchange for a big gain in workload portability.

In addition to portability, Docker injects a DevOps flavor to the workload package. DevOps requires a higher level of cooperation between developers and operations managers. By accepting the Docker format, developers can produce code without worrying much about where it's going to run. Developers who change code can find their changes automatically tested and added to the correct layer in the Docker workload, without the developer being burdened with maintenance. Operations managers can accept code that's already been tested, certified it's been formatted in a standard way, and guaranteed to be isolated from other code in a production environment. With Docker, developers and operations, two groups that have perennially been at war, can sit down at a table where a truce could break out and make it easier way for both sides to get their jobs done.

On the opening day of the conference, Microsoft CEO Satya Nadella tweeted about a blog post at Microsoft.com about Docker running on Azure, noting Docker was "developer goodness."

With IBM, Google, Rackspace, Red Hat, and many other backing the emergence of Docker containers, it wasn't surprising that Stuart Miniman, principal research contributor and tech analyst at Wikibon, said in another tweet: "Fun fact -- Docker currently has 42 employees. Is it the answer to life, the universe, and everything?"

If enterprise IT is already committed to virtualization, will Linux containers supplant that? Can Docker with 42 employees displace

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Charles Babcock is an editor-at-large for InformationWeek, having joined the publication in 2003. He is the former editor-in-chief of Digital News, former software editor of Computerworld and former technology editor of Interactive Week. He is a graduate of Syracuse ... View Full Bio
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Laurianne
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Laurianne,
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6/19/2014 | 3:48:12 PM
Re: Online Migration of Containers works
Charlie, what do you make of the security questions being asked around containers in the past few days? Was this a big topic in thre halls at Structure conference?
Charlie Babcock
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Charlie Babcock,
User Rank: Author
6/16/2014 | 3:13:27 PM
Re: Online Migration of Containers works
Good point, Neuroserve. I think it should be possible to move containers around among like hosts, increasing server utilization and energy efficiency. Just because we're not there yet doesn't mean we won't get there. In some ways, containers should be easier to migrate than VMs. But it will help if there is one management system to do both.
neuroserve
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neuroserve,
User Rank: Apprentice
6/14/2014 | 2:45:59 AM
Online Migration of Containers works
You write: "Workloads can be moved around while running to maximize utilization of servers -- containers cannot."

That is probably true for the current state of Docker containers. Live migration of OpenVZ containers works for a very long time already. If you have a recent Linux kernel you probably have the patches from CRIU (criu.org) and should be able to do "checkpoint and restore" with "normal" containers, as well. If you use ploop for your container images, your live migrations can be very fast. I'm looking forward to see criu and ploop used with docker. But with Docker there seems to come a "doctrine", that favours short running containers instead of long running ones (hypervisor based VMs are also long running). Container = Application is the mantra here (ore more specific: One instance of an application is one container - just like Google does it).

Neuroserve
Charlie Babcock
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Charlie Babcock,
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6/13/2014 | 6:27:06 PM
About that $10, Joshua...
By unlikely allies, I mean Red Hat, IBM and Rackspace, among others. For months, Red Hat has seen the value of Docker, worked closely with Docker Inc. and moved to get Docker containerization inserted into Open Stack through a PaaS approach in Project Solum. Meanwhile, IBM and Rackspace put their money down on Cloud Foundry, with its different approach to PaaS. Piston's Joshua McKenty even bet $10 that Red Hat would join Cloud Foundry by the end of the year. At DockerCon, all the movement was in the other direction. Rackspace CTO John Engates praised Project Solum from the podium. IBM cited Docker's efficiencies and Cloud Foundry announced it was a Docker backer too. Instead of Red Hat joining Cloud Foundry, it looks like Cloud Foundry members are trying to catch up with Red Hat. 
TeaPartyCitizen
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TeaPartyCitizen,
User Rank: Apprentice
6/13/2014 | 6:17:17 PM
It never would have been a big deal
If Unix and Linux had seperate name spaces per process by default when Unix was invented and had the ability to share name spaces with groups, containers would have never been a big deal. People would have always programmed like that and the paradigms and models would all be very mature by now. It's not like we needed the Higgs Bozon descovered inorder to develope this feature. I'm just saying it could have been done earlier. That said, containers will make a release engineer's eyes glow. I saw this when I first learned of them.
Charlie Babcock
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Charlie Babcock,
User Rank: Author
6/12/2014 | 4:32:57 PM
Containers below the radar of most systems management
Laurie, Kubernetes could be the next big thing in open source code. If we get a proliferation of Linux containers, The need to create, deploy and manage them will overwhelm IT because they'll be outside the view of virtual machine and physical systems management, Is Kubernetes up to the job?

 
Laurianne
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Laurianne,
User Rank: Author
6/12/2014 | 12:58:57 PM
Kubernetes
I had not heard of Kubernetes befire this week, and I'm guessing many people had not heard of Docker. Charlie brings some useful context to why containers have quickly become a polarizing topic in cloud.
Google in the Enterprise Survey
Google in the Enterprise Survey
There's no doubt Google has made headway into businesses: Just 28 percent discourage or ban use of its productivity ­products, and 69 percent cite Google Apps' good or excellent ­mobility. But progress could still stall: 59 percent of nonusers ­distrust the security of Google's cloud. Its data privacy is an open question, and 37 percent worry about integration.
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