What are user namespaces? Sticking with the apartment complex analogy, the numbering of users and groups have historically been the same in every container and in the underlying host, just like public channel 10 is generally the same in every unit in an apartment building.
But, imagine that people in different apartments are getting their television signal from different cable and satellite companies. Channel 10 is now different for for each person. It might be sports for one person, and news for another.
Historically, in the Linux kernel, there was a single data structure which held users and groups. Starting in kernel version 3.8
Continue reading “What’s Next for Containers? User Namespaces”
In a recent blog post on the appc spec, I mentioned Project Atomic’s evolving Nulecule [pronounced: noo-le-kyul] spec as an attempt to move beyond the current limitations of the container model. Let’s dig a bit deeper into that.
Continue reading “The Atomic App Concept…”It All Starts When a Nulecule Comes Out of its Nest””
It Started with Developers
Developers were the first adopters of containers for application creation. Now that containers have made their way into production environments, operations teams are starting to look deeper at what benefit they bring. Deployments are a key focus not just because the container model is so different, but also because there are automation integration points that have been previously unavailable.
Release engineers are faced with a tough question: continue to do rolling style updates as they always have or move to a red/black deployment model. Both have their pros and cons but using containers with red/black deployment methods provides
Continue reading “Stop Gambling with Upgrades, Murphy’s Law Always Wins”
At this week’s CoreOS Fest in San Francisco, CoreOS is – unsurprisingly – pushing hard on the Application Container Spec (appc) and its first implementation, rkt, making it the topic of the first session after the keynote and a bold story about broad adoption.
When making technology decisions, Red Hat continuously evaluates all available options with the goal of selecting the best technologies that are supported by upstream communities. This is why Red Hat is engaging upstream in appc to actively contribute to the specification.
Red Hat engages in many upstream communities. However, this engagement should not imply full support, or that we consider appc or rkt ready for
Continue reading “rkt, appc, and Docker: A Take on the Linux Container Upstream”
Linux containers have been getting a lot of hype recently, and it’s easy to understand why. Delivering applications to meet the demands of the business is challenging and containers are disrupting traditional application development and deployment models, enabling businesses to explore new, better ways to deliver products and services.
New innovations like the Docker image format and Kubernetes give you a simpler way to quickly create, package, assemble, and distribute applications. But with hype comes misunderstandings and misconceptions.
Join Red Hat and Cisco tomorrow, May 5, 2015 at 11:00 AM ET / 8:00 AM PT for the webcast, Top 6 Misconceptions about Linux Containers, to gain clarity around these misconceptions. In the webcast, you will:
- Gain a pragmatic look at Linux containers.
- Understand what benefits containers can deliver for you.
- Discover what security, implementation, and other considerations you should understand before your organization embraces this technology.
If you haven’t already done so, register today.
Here on the Red Hat Enterprise Linux Blog we’ve dedicated a number of posts to containers and a variety of associated Red Hat solutions. Whether you’re seeking to deploy Red Hat Enterprise Linux 6 applications on Red Hat Enterprise Linux 7 as containers, hoping to better understand how atomic updates work, or are simply out to learn all you can about Red Hat Enterprise Linux Atomic Host – there’s likely a post (here) with the information you need. However, we’ve yet to really explore container orchestration. To this end, I invite you to read this new post from Red Hat’s own Joe Fernandes. Joe talks about Kubernetes, Google’s tool for managing clusters of Linux containers, its progenitor (i.e Google’s Borg), and how Red Hat is building on top of Kubernetes to bring web-scale container infrastructure to enterprise customers.
If you’re working with container images on Red Hat Enterprise Linux 7.1 or Red Hat Enterprise Linux Atomic Host, you might have noticed that the search and pull behavior of the included docker tool works slightly differently than it does if you’re working with that of the upstream project. This is intentional.
When we started the planning process for containers in RHEL 7.1, we had 3 goals in mind:
- Give control over the search path to the end-user administrator
- Enable a federated approach to search and discovery of docker-formatted container images
- Support the ability for Red Hat customers to consume container images and other content included as part of their Red Hat Subscription
The changes we implemented, which are documented on the Red Hat Customer Portal, affect three different areas of the tool:
Continue reading “Understanding the Changes to ‘docker search’ and ‘docker pull’ in Red Hat Enterprise Linux 7.1”
Yesterday, at Red Hat’s annual North America Partner Conference (in Orlando, FL), Dave Bartoletti, principal analyst with Forrester Research, told hundreds of attendees about a recently completed market research program undertaken by Forrester and sponsored by Red Hat. In this study, 194 developers and IT decision-makers at mid- to large-size companies were surveyed as to their plans and expectations for container technologies.
What they shared, indicates that
Continue reading “Forrester’s Dave Bartoletti Reports on Container Usage at Red Hat Partner Conference”
Earlier in March we announced the general availability of Red Hat Enterprise Linux 7 Atomic Host, a small footprint, container host based on Red Hat Enterprise Linux 7. It provides a stable host platform, optimized for running application containers, and brings a number of application software packaging and deployment benefits to customers. In my previous container blog I gave the top seven reasons to deploy Red Hat Enterprise Linux 7 Atomic Host. One reason was the ability to do atomic updates and rollbacks. In this blog I provide an in-depth look into atomic updating and how it differs from a yum update. And, speaking of atomic updates
Continue reading “Red Hat Enterprise Linux Atomic Host: Updates Made Easy”
Over the last 18 months, especially since the general availability of Red Hat Enterprise Linux 7, “containers” have emerged as a hot topic. With the more recent introduction of Red Hat Enterprise Linux Atomic Host, an operating system optimized for running the next generation of applications with Linux containers, one might wonder… what about virtualization? In that the benefits of containerization seem to overlap those of traditional virtualization, how do organizations know when to pick one approach over the other?
Continue reading “Virtual Machines or Containers? Maybe Both?”