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
• Download and install
• Quick start for developers
• Architecture overview
• Configuration
• Logging
• 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 the
virtcontainers
package to provide a high-performance standards-compliant runtime that creates
hardware-virtualized Linux containers running on Linux hosts.

The runtime is
OCI-compatible,
CRI-O-compatible, and
Containerd-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 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 capable
of 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 the
  list of all the checks performed.

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

Download and install

See the installation guides
available for various operating systems.

Quick start for developers

See the
developer guide.

Architecture overview

See the architecture overview
for 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 have
specific requirements.

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 below command lists the full paths to the configuration files that the
runtime 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 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 also 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.

Limitations

See the
limitations file
for further details.

Community

See the community repository.

Contact

See how to reach the community.

Further information

See the
project table of contents
and the
documentation repository.

Additional packages

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