Containers: has their ship come in?

VMs vs containerisation

There is a certain irony that the ease of provisioning and using virtual machines has contributed to their own potential demise. If it weren’t for the sprawl, the extra density that containerisation provides may well be less tempting in the real world. “It’s collapsed under it’s own success,” jokes Sjoquist.

Unsurprisingly, VMware disagrees. The company, which has dominated the hypervisor industry, says you still need machines somewhere, and VMs are still the best way to host applications – even when they’re in containers.

“The virtual machine has been, and continues to be, the best place for an operating system to live. Where you see containerisation come into play is on the top of that,” says Aaron Steppat, senior product marketing manager, software-defined data centre, at VMware Australia & New Zealand.

“Because the container doesn’t actually hold an operating system. It contains the necessary libraries and code – the application stack itself – and it relies upon the libraries that are provided through a Linux operating system.”

Steppat says it’s not a case of choosing between virtual machines and containerisation. “It’s not an ‘either/or’; it’s an ‘and’. ”

Sjoquist says that with the advent of OS-level virtualisation, hypervisors can now be seen as clunky: “If you have this heavy, fat hypervisor strategy that doesn’t allow you to be agile, then you may well consider going back to bare metal.”

But he warns that one needs economies of scale before doing anything too dramatic. “Until you get to a significant scale, there’s still a lot to be said about having a hypervisor layer in there.”

As a major commercial player in the Linux world, open source vendor Red Hat is watching the containerisation fad with glee. Red Hat Australia’s platform business unit senior manager, Colin McCabe, tells CRN that once an organisation decides to switch to containers, it will consider the hypervisor layer redundant – but any transition will be gradual.

“The organisation will start asking, ‘Why would we spend money on yet another layer? Why would you be running containers on a OS that lives on a hypervisor?’ There will be some that retain virtual machines, but the majority will say, ‘Let’s dump everything that we’ve already got [into containers]. But it will be a stepped approach – some apps will end up over here and some apps will end up over there.”

Docker ain’t a container

The need for portability and agility also favours containerisation. Without the overhead of an entire operating system, containers can be moved and copied around to whatever hosts the administrator desires. Once it sits on the right host, the start-up speed is remarkable, only taking a few seconds. An application is running almost instantly, not waiting for a server to be booted.

Such agility is further enhanced with container management tools like Docker. The open source software is the hottest name in technology at the moment, with a slew of industry giants – including Amazon Web Services and Microsoft – coming out in support, as well as many of the specialist containerisation vendors.

However, there is a misunderstanding by some that Docker itself provides containers.

“Docker automates the deployment of applications into containers,” says Neil Morarji, ANZ general manager for containerisation vendor Parallels. “It manages the taking of applications from one environment to another, through the development cycle, and takes care of multiple people working on the applications.” 

Parallels is the manufacturer of containerisation technology Virtuozzo. Its Asia-Pacific sales engineer, Alexei Anisimov, explains that Docker is an excellent complement to OS-level virtualisation. “Docker really makes it easier to create applications that are specifically designed for container technology. It makes it easy to deploy and run them. That’s why they’re an ideal partner for us.”

Next: Leaky containers make a mess