fa9b15dafe
When our runtime is asked for the container status, we also handle the scenario where the container is stopped if the shim process for that container on the host has terminated. In the current implementation, we retrieve the container status before stopping the container, causing a wrong status to be returned. The wait for the original go-routine's completion was done in a defer within the caller of statusContainers(), resulting in the statusContainer()'s values to return the pre-stopped value. This bug is first observed when updating to docker v18.09/containerd v1.2.0. With the current implementation, containerd-shim receives the TaskExit when it detects kata-shim is terminating. When checking the container state, however, it does not get the expected "stopped" value. The following commit resolves the described issue by simplifying the locking used around the status container calls. Originally StatusContainer would request a read lock. If we needed to update the container status in statusContainer, we'd start a go-routine which would request a read-write lock, waiting for the original read lock to be released. Can't imagine a bug could linger in this logic. We now just request a read-write lock in the caller (StatusContainer), skipping the need for a separate go-routine and defer. This greatly simplifies the logic, and removes the original bug. Fixes #926 Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
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
- Quick start for users
- Quick start for developers
- Architecture overview
- Configuration
- Logging
- Debugging
- Limitations
- Community
- Further information
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 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:
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
rootuser, further checks will be performed (e.g. it will check if another incompatible hypervisor is running):$ sudo kata-runtime kata-check
Quick start for users
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 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.
Limitations
See the limitations file for further details.
Community
Contact
See how to reach the community.
Further information
See the project table of contents and the documentation repository.