I'm trying to change the CPU Manager Policy for a Kubernetes cluster that I manage, as described here however, I've run into numerous issues while doing so.
The cluster is running in DigitalOcean and here is what I've tried so far.
--cpu-manager-policy
is a kubelet option I assume that I cannot change it via the API Server and have to change it manually on each node. (Is this assumption BTW?)ssh
into one of the nodes (droplets in DigitalOcean lingo) and run kubelet --cpu-manager-policy=static
command as described in the kubelet CLI reference here. It gives me the message Flag --cpu-manager-policy has been deprecated, This parameter should be set via the config file specified by the Kubelet's --config flag. See https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/ for more information.
ps aux | grep kubelet
and find that its /etc/kubernetes/kubelet.conf
.cpuManagerPolicy: static
to it, and also kubeReserved
and systemReserved
because they become required fields if specifying cpuManagerPolicy
.I'm a little lost about the following things
It might not be the global way of doing stuff, but I think it will be much more comfortable than what you are currently doing.
First you need to run kubectl proxy --port=8001 &
Download the configuration:
NODE_NAME="the-name-of-the-node-you-are-reconfiguring"; curl -sSL "http://localhost:8001/api/v1/nodes/${NODE_NAME}/proxy/configz" | jq '.kubeletconfig|.kind="KubeletConfiguration"|.apiVersion="kubelet.config.k8s.io/v1beta1"' > kubelet_configz_${NODE_NAME}
Edit it accordingly, and push the configuration to control plane. You will see a valid response if everything went well. Then you will have to edit the configuration so the Node starts to use the new ConfigMap. There are many more possibilities, for example you can go back to default settings if anything goes wrong.
This process is described with all the details in this documentation section.
Hope this helps.
One issue with Dynamic Configuration is that in case the node fails to restart, the API does not give a reasonable response back that tells you what you did wrong, you'll have to ssh
into the node and tail the kubelet logs. Plus, you have to ssh
into every node and set the --dynamic-config-dir
flag anyways.
The folllowing worked best for me
vim /etc/systemd/system/kubelet.service
--cpu-manager-policy=static \
--kube-reserved=cpu=1,memory=2Gi,ephemeral-storage=1Gi \
--system-reserved=cpu=1,memory=2Gi,ephemeral-storage=1Gi \
We need to set the --kube-reserved
and --system-reserved
flags because they're prerequisties to setting the --cpu-manager-policy
flag
rm -rf /var/lib/kubelet/cpu_manager_state
sudo systemctl daemon-reload
sudo systemctl stop kubelet
sudo systemctl start kubelet
kubectl proxy
on port 8001.curl -sSL "http://localhost:8001/api/v1/nodes/${NODE_NAME}/proxy/configz" | grep cpuManager