07db945b09
There is a relation between the maximum number of vCPUs and the
memory footprint, if QEMU maxcpus option and kernel nr_cpus
cmdline argument are big, then memory footprint is big, this
issue only occurs if CPU hotplug support is enabled in the kernel,
might be because of kernel needs to allocate resources to watch all
sockets waiting for a CPU to be connected (ACPI event).
For example
```
+---------------+-------------------------+
| | Memory Footprint (KB) |
+---------------+-------------------------+
| NR_CPUS=240 | 186501 |
+---------------+-------------------------+
| NR_CPUS=8 | 110684 |
+---------------+-------------------------+
```
In order to do not affect CPU hotplug and allow to users to have containers
with the same number of physical CPUs, this patch tries to mitigate the
big memory footprint by using the actual number of physical CPUs as the
maximum number of vCPUs for each container if `default_maxvcpus` is <= 0 in
the runtime configuration file, otherwise `default_maxvcpus` is used as the
maximum number of vCPUs.
Before this patch a container with 256MB of RAM
```
total used free shared buff/cache available
Mem: 195M 40M 113M 26M 41M 112M
Swap: 0B 0B 0B
```
With this patch
```
total used free shared buff/cache available
Mem: 236M 11M 188M 26M 36M 186M
Swap: 0B 0B 0B
```
fixes #295
Signed-off-by: Julio Montes <julio.montes@intel.com>
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|---|---|---|
| .ci | ||
| .github | ||
| arch | ||
| cli | ||
| data | ||
| vendor | ||
| virtcontainers | ||
| .gitignore | ||
| .gitmodules | ||
| .pullapprove.yml | ||
| .travis.yml | ||
| CODE_OF_CONDUCT.md | ||
| CONTRIBUTING.md | ||
| Gopkg.lock | ||
| Gopkg.toml | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| VERSION | ||
| versions.yaml | ||
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 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:
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 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.