VMware with 14,000? Can containers live up to what they seem to promise?
There's a tenuous relationship between containers and lightweight virtualization. Sun Microsystems executives used to refer to Solaris containerization as Sun's answer to virtualization. Both VMs and containers supply workload isolation on a shared host, but it wasn't an adequate Sun answer to virtualization. Sun later introduced its own version of Xen. Containers and VMs are also different -- enough so that replacement of VMs by containers any time soon in the enterprise looks highly unlikely.
The larger question is whether VMware, in virtualizing legacy systems and dominating the enterprise data center, is somehow not the right party to lead the management of the next generation of applications. Few people are more aware of this question than executives at VMware. They are trying their utmost to move beyond legacy systems into applications for the cloud and to become a supplier of hybrid cloud services. The spinning out of Pivotal from VMware and the establishment of an independent Cloud Foundry PaaS are key parts of VMware's effort to stay relevant to developers.
With those moves, its data center dominance, and its vCloud Hybrid Service, VMware is in a theoretically good position to realize its ambitions to extend virtualization beyond the enterprise data center into hybrid cloud operations. But I think Linux containers will in fact act as a curb on how far the VMware hypervisor-based software horizon can expand.
Containerization is going to have an appeal for the next generation of developers, partly because it can't be matched in every way by sophisticated virtualization tools and management. There's evidence from IBM that containers deploy more quickly and run more efficiently than virtual machines. They can also be more densely packed on servers. That's a big plus in the cloud, where overall efficiency remains a litmus test of who will thrive and who will die.
Containerization "is an important way to get standardization at the sub-virtual machine level, allowing portable apps to be packaged in a lightweight fashion and be easily and reliably consumed by PaaS clouds everywhere," wrote IDC software analyst Al Hilwa from the DockerCon 2014 event.
Cloud computing based on vCloud Hybrid Service will have ESX Server hypervisors in both the data center and public cloud. No hypervisor is required for cloud computing based on Docker, a point Google plans to illustrate with its Compute Engine service.
On the other hand, Docker workloads can be deployed in virtual machines, if the user chooses. It is conceivable containers and virtual machines will be used hand-in-glove in some cloud settings. In others, containers will run by themselves on bare metal for maximum efficiency.
For the foreseeable future, virtualization has several management advantages in the enterprise data center, with its potpourri of legacy applications. Those applications can be made independent of the hardware they were launched on and managed with pooled resources. Workloads can be moved around while running to maximize utilization of servers -- containers cannot. But the software-defined data center doesn't necessarily rule out Linux containers. They can be fit in alongside VMs.
The next generation of applications, many of which will run in the cloud, are more likely to be built with containers in mind rather than virtualization. When applications are composed as assemblies of many moving and distributed parts, containers will be a better fit.
Google VP of Infrastructure Eric Brewer in a keynote Tuesday said that containers have been critical to how Google does cloud computing. In a blog post the same day, he said, "Everything at Google, from search to Gmail, is packaged and run in a Linux container. Each week we launch more than 2 billion container instances across our global data centers, and the power of containers has enabled both more reliable services and higher, more-efficient scalability."
Google also released Tuesday a container management system, Kubernetes, as open source code. Google uses Kubernetes to manage those 2 billion container instances, but few details of its operation are known yet. Nevertheless, other cloud providers and builders of enterprise private clouds now have a management system to start with.
As a better understanding of attributes of containerization emerges, it will be the tools to create and manage them that will take center stage. It's too soon to know how flexibly containers will be managed or migrated, or the future tasks they may be able to undertake. But the giant step represented by the move to virtualization in the data center appears about to be repeated, this time with containerization in the cloud.
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