Runtime

This repository contains the runtime for the Kata Containers project.

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

• Introduction
• License
• Platform support
  • Hardware requirements
• Quick start for developers
• Configuration
• Logging
• Debugging
• Community

Introduction

kata-runtime, referred to as "the runtime", is the Command-Line Interface (CLI) part of the Kata Containers runtime component. It leverages the virtcontainers package to provide a high-performance standards-compliant runtime that creates hardware-virtualized containers.

The runtime is both OCI-compatible and CRI-O-compatible, allowing it to 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 following technologies:

• Intel's VT-x technology.
• ARM's Hyp mode (virtualization extension).

Hardware requirements

The runtime has a built-in command to determine if your host system is capable of running a Kata Container:

$ kata-runtime kata-check

Note:

If you run the previous command as the root user, further checks will be performed (e.g. it will check if another incompatible hypervisor is running):

$ sudo kata-runtime kata-check

Quick start for developers

See the developer guide.

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 might need to modify this file if you have specialist needs.

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

The command below lists the full paths to the configuration files that the runtime attempts to load. The first path that exists is used:

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

Aside from the built-in locations, it is possible to specify the path to a custom 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. See the logging section for further details.

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

$ kata-runtime kata-env

Logging

The runtime provides --log= and --log-format= options. However, the runtime always logs to the system log (syslog or journald).

To view runtime log output:

$ sudo journalctl -t kata-runtime

For detailed information and analysis on obtaining logs for other system components, see the documentation for the kata-log-parser tool.

Debugging

See the debugging section of the developer guide.

Community

See the community repository.