Kata Containers now available in Tumbleweed

Kata Containers is an open source container runtime that is crafted to seamlessly plug into the containers ecosystem.

We are now excited to announce that the Kata Containers packages are finally available in the official openSUSE Tumbleweed repository.

It is worthwhile to spend few words explaining why this is a great news, considering the role of Kata Containers (a.k.a. Kata) in fulfilling the need for security in the containers ecosystem, and given its importance for openSUSE and Kubic.

What is Kata

As already mentioned, Kata is a container runtime focusing on security and on ease of integration with the existing containers ecosystem. If you are wondering what’s a container runtime, this blog post by Sascha will give you a clear introduction about the topic.

Kata should be used when running container images whose source is not fully trusted, or when allowing other users to run their own containers on your platform.

Traditionally, containers share the same physical and operating system (OS) resources with host processes, and specific kernel features such as namespaces are used to provide an isolation layer between host and container processes. By contrast, Kata containers run inside lightweight virtual machines, adding an extra isolation and security layer, that minimizes the host attack surface and mitigates the consequences of containers breakout. Despite this extra layer, Kata achieves impressive runtime performances thanks to KVM hardware virtualization, and when configured to use a minimalist virtual machine manager (VMM) like Firecracker, a high density of microVM can be packed on a single host.

If you want to know more about Kata features and performances:

• katacontainers.io is a great starting point.
• For something more SUSE oriented, Flavio gave a interesting talk about Kata at SUSECON 2019,
• Kata folks hang out on katacontainers.slack.com, and will be happy to answer any quesitons.

Why is it important for Kubic and openSUSE

SUSE has been an early and relevant open source contributor to containers projects, believing that this technology is the future way of deploying and running software.

The most relevant example is the openSUSE Kubic project, that’s a certified Kubernetes distribution and a set of container-related technologies built by the openSUSE community.

We have also been working for some time in well known container projects, like runC, libpod and CRI-O, and since a year we also collaborate with Kata.

Kata complements other more popular ways to run containers, so it makes sense for us to work on improving it and to assure it can smoothly plug with our products.

How to use

While Kata may be used as a standalone piece of software, it’s intended use is serve as a runtime when integrated in a container engine like Podman or CRI-O.

This section shows a quick and easy way to spin up a Kata container using Podman on openSUSE Tumbleweed.

First, install the Kata packages:

$ sudo zypper in katacontainers

Make sure your system is providing the needed set of hardware virtualization features required by Kata:

$ sudo kata-runtime kata-check

If no errors are reported, great! Your system is now ready to run Kata Containers.

If you haven’t already, install podman with:

$ sudo zypper in podman

That’ all. Try running a your first Kata container with:

$ sudo podman run -it --rm --runtime=/usr/bin/kata-runtime opensuse/leap uname -a
Linux ab511687b1ed 5.2.5-1-kvmsmall #1 SMP Wed Jul 31 10:41:36 UTC 2019 (79b6a9c) x86_64 x86_64 x86_64 GNU/Linux

Differences with runC

Now that you have Kata up and running, let’s see some of the differences between Kata and runC, the most popular container runtime.

When starting a container with runC, container processes can be seen in the host processes tree:

...
10212 ?        Ssl    0:00 /usr/lib/podman/bin/conmon -s -c <ctr-id> -u <ctr-id>
10236 ?        Ss     0:00  \_ nginx: master process nginx -g daemon off;
10255 ?        S      0:00      \_ nginx: worker process
10256 ?        S      0:00      \_ nginx: worker process
10257 ?        S      0:00      \_ nginx: worker process
10258 ?        S      0:00      \_ nginx: worker process
...

With Kata, container processes are instead running in a dedicated VM, so they are not sharing OS resources with the host:

...
10651 ?        Ssl    0:00 /home/marco/go/src/github.com/containers/conmon/bin/conmon -s -c <ctr-id> -u <ctr-id>
10703 ?        Sl     0:01  \_ /usr/bin/qemu-system-x86_64 -name sandbox-<ctr-id> -uuid e54ee910-2927-456e-a180-836b92ce5e7a -machine pc,accel=kvm,kernel_ir
10709 ?        Ssl    0:00  \_ /usr/lib/kata-containers/kata-proxy -listen-socket unix:///run/vc/sbs/<ctr-id>/proxy.sock -mux-socket /run/vc/vm/829d8fe0680b
10729 ?        Sl     0:00  \_ /usr/lib/kata-containers/kata-shim -agent unix:///run/vc/sbs/<ctr-id>/proxy.sock -container <ctr-id>
...

Future plans

We are continuing to work to offer you a great user experience when using Kata on openSUSE by:

• improving packages quality and stability,
• delivering periodic releases,
• making sure that Kata well integrates with the other container projects, like Podman and CRI-O.

As a longer term goal, we will integrate Kata in the Kubic distribution and in CaaSP, to make them some of the most complete and secure solutions to manage containers.