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VMware’s solution for building and managing a container infrastructure is still in its infancy. Learn what it is, and what it can do for you.
ontainers are the new black. While Docker and Kubernetes are the top names among the container-obsessed DevOps faithful, other vendors and technologies are seeking to make their mark. VMware, king of the on-premises hypervisor market, seeks dominance of the container world
with Photon. What is Photon, and where does it fit? What does the VMware administrator need to know?
CONTAINERS VS. VIRTUAL MACHINES
Before I delve into Photon itself, a quick primer on containers vs. hypervisor-based virtual machines (VMs) is called for. In very broad strokes, hypervisors take a file and treat it like a virtual hard drive. An OS is installed onto this virtual hard drive, including file systems, boot sectors and all the trappings of a full-blown OS.
A hypervisor “runs” the VM by presenting VMs with emulated or shared hardware. Applications installed into a VM are installed onto the file system that occupied the virtual hard drive, and otherwise generally don’t know or care that the computer they occupy is a carefully manufactured fake.
Containers are different. At their most basic, containers are little more than “jails” that lie to the contents of the container about where they’re installed. You might install your application to /usr/ jails/somecontainer, but what’s in the container believes itself to be installed somewhere else; /usr/local/someapplication, for example.
Done right, containers can’t see one another’s file systems or pro- cesses, but can see some of the host’s file systems and processes. This concept—that applications can be lied to about where they’re installed or what other processes they share an OS with—is the most important one when dealing with containers.
You’ll notice that I said, “What’s installed in a container.” This is because containers aren’t as straightforward as VMs. There are many different container technologies and they come with different levels of abstraction.
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