Runtime

This repository contains the runtime for theKata Containers project.

For details of the other Kata Containers repositories, see therepository summary.

• Introduction
• License
• Platform support
  • Hardware requirements
• Download and install
• Quick start for developers
• Architecture overview
• Configuration
• Logging
  • Kata OCI
  • Kata containerd shimv2
• Debugging
• Limitations
• Community
  • Contact
• Further information
• Additional packages

Introduction

kata-runtime, referred to as "the runtime", is the Command-Line Interface(CLI) part of the Kata Containers runtime component. It leverages thevirtcontainerspackage to provide a high-performance standards-compliant runtime that createshardware-virtualized Linux containers running on Linux hosts.

The runtime isOCI-compatible,CRI-O-compatible, andContainerd-compatible,allowing itto work seamlessly with both Docker and Kubernetes respectively.

License

The code is licensed under an Apache 2.0 license.

See the license file for further details.

Platform support

Kata Containers currently works on systems supporting the followingtechnologies:

• Intel VT-x technology.
• ARM Hyp mode (virtualization extension).
• IBM Power Systems.
• IBM Z mainframes.

Hardware requirements

The runtime has a built-in command to determine if your host system is capableof running and creating a Kata Container:

$ kata-runtime kata-check

Note:

• By default, only a brief success / failure message is printed.If more details are needed, the --verbose flag can be used to display thelist of all the checks performed.

• root permission is needed to check if the system is capable of runningKata containers. In this case, additional checks are performed (e.g., if anotherincompatible hypervisor is running).

Download and install

See the installation guidesavailable for various operating systems.

Quick start for developers

See thedeveloper guide.

Architecture overview

See the architecture overviewfor details on the Kata Containers design.

Configuration

The runtime uses a TOML format configuration file called configuration.toml.The file contains comments explaining all options.

Note:

The initial values in the configuration file provide a good default configuration.You may need to modify this file to optimise or tailor your system, or if you havespecific requirements.

Since the runtime supports astateless system,it checks for this configuration file in multiple locations, two of which arebuilt in to the runtime. The default location is/usr/share/defaults/kata-containers/configuration.toml for a standardsystem. However, if /etc/kata-containers/configuration.toml exists, thistakes priority.

The below command lists the full paths to the configuration files that theruntime attempts to load. The first path that exists will be used:

$ kata-runtime --kata-show-default-config-paths

Aside from the built-in locations, it is possible to specify the path to acustom configuration file using the --kata-config option:

$ kata-runtime --kata-config=/some/where/configuration.toml ...

The runtime will log the full path to the configuration file it is using. Seethe logging section for further details.

To see details of your systems runtime environment (including the location ofthe configuration file being used), run:

$ kata-runtime kata-env

Logging

For detailed information and analysis on obtaining logs for other systemcomponents, see the documentation for thekata-log-parsertool.

For runtime logs, see the following sections for the CRI-O and containerd shimv2 based runtimes.

Kata OCI

The Kata OCI runtime (including when used with CRI-O), provides --log= and --log-format= options.However, the runtime also always logs to the system log (syslog or journald).

To view runtime log output:

$ sudo journalctl -t kata-runtime

Kata containerd shimv2

The Kata containerd shimv2 runtime logs through containerd, and its logs will be sentto wherever the containerd logs are directed. However, theshimv2 runtime also always logs to the system log (syslog or journald) under theidentifier name of kata.

To view the shimv2 runtime log output:

$ sudo journalctl -t kata

Debugging

See thedebugging section of the developer guide.

Limitations

See thelimitations filefor further details.

Community

See the community repository.

Contact

See how to reach the community.

Further information

See theproject table of contentsand thedocumentation repository.

Additional packages

For details of the other packages contained in this repository, see thepackage documentation.