rt-operator

Experimental Kubernetes operator supporting containers with real-time threads on a cgroups v1 host like RHEL 7/CentOS 7. This operator runs a service on the host with a path to credentials for the cluster. As pod(s) are deployed with the following annotations present, the pod's containers' cgroup will be modified to have necessary capabilities to run real-time threads.

annotations:
  realtime: "true"
  rt_runtime_us: "25000"

Where

• realtime: set to either "true" or "false"
• rt_runtime_us: set to this container's rt_runtime_us value in microseconds

See example/threadtest.yaml for full pod deployment yaml showing the annotations. See CJLove/thread-playground for the source for building a container with real-time threads.

Container runtimes supported:

• containerd
• docker
• cri-o

Dependencies

• Python3
• Modules: kubernetes and its dependencies (see requirements.txt)

Building wheel

$ python3 setup.py bdist_wheel

Installing wheel

# pip3 install rt_operator-0.1.0-py3-none-any.wh

Running under systemd

Installing and enabling

• Adjust paths in rt-operator.service as necessary
• Adjust After setting in rt-operator.service to after the Kubelet.service for Kubernetes or k3s.service for K3S

$ sudo cp /usr/local/service/rt-operator.service /etc/systemd/system/
$ sudo systemctl enable rt-operator
$ sudo systemctl start rt-operator

Configuration

Settings in /usr/local/etc/rt-operator.yaml config file:

---
### rt-operator configuration settings

# Log level: WARN | INFO | DEBUG 
log_level: "DEBUG"

# Full path to kubernetes credentials file (override ~/.kube/config)
kube_path: /path/to/.kube/config

# Override system hostname used for comparisons with pod's node allocation
node_name: myhostname

# Override cgroup handler: noop | cgroup_v1 | cgroup_v2
# cgroup_handler: noop

# Override cgroup v1 handler settings:
# cpu.rt_runtime_capacity for all real-time pods on this node
cgroup_v1_capacity: 950000

Monitoring & Logs

$ systemctl status rt-operator
$ journalctl -u rt-operator -f