We are using containers (namely OpenVZ) more then 6 years now in production. And we are very happy with the solution. Till now when mentioning “virtualization” or VPS everybody thought about VMWare, KVM (used also by Amazon), OpenStack and similar “full” virtualization platforms – while compared to containers, in our view, such fully virtualized machines were much clumsier and heavier on the underlying host.

From the first time we tried containers we knew this is the right technology for our needs – and not just because it reminded us about FreeBSD’s jails. Containers enable much higher density, simpler operations and greater flexibility than fully virtualized alternatives. We could simply and swiftly create, clone, deploy ant put into operation many production servers on one host (mostly mail, web and database servers), make fine tuning concerning resource commitments and load balancing.

These containers are easy to backup using LVM snapshots and since the root directories of containers resides in the same file system of the main physical server its easy to move files around between individual containers. The biggest advantage though is that all containers are using the same single kernel instance – a single running kernel is used by the main host machine as well as by all the containers. The isolation is made on the process and filesystem level. This approach is very efficient and enables much higher density of containers than fully virtualized VPSs.

There are some disadvantages – though not so serious from our point of view. One drawback is that you can not use different kernels for each of your containers. The kernel installed and booted by your main host is used by all containers. The second disadvantage is – that you can not run other types of operating system than Linux. But who needs or uses Windows as a serious internet server anyhow?

It looks like containers are gaining recognition these days [1, 2]. Docker and Cubernates are often mentioned.  In our view Parallels division (today Virtuozzo) and Proxmox are pioneers in this respect. In the last Proxmox version the authors changed the containerization platform from OpenVZ to LXC (LinuX Containers). We have a host with LXC too and so far we did not experienced any difficulties.

It looks containers achieved their maturity and they are becoming a hype these days. Ultimately the winner will be anybody who will be able to make any competitive advantage out of containers’ capabilities.

References

  1. Virtuozzo’s new Kernel-based Virtual Machine for ISPs is a ‘huge thing,’ years in the making
    BY DAN RICHMAN on July 25, 2016 at 6:00 am
  2. The incredible shrinking operating system: How containers and serverless computing are changing the cloud
    BY TOM KRAZIT on October 26, 2017 at 7:00 am

 

Containers Hype
Tagged on:                                 

Leave a Reply