Ensure that the --streaming-connection-idle-timeout argument is not set to 0

Description:

Do not disable timeouts on streaming connections.

Rationale:

Setting idle timeouts ensures that you are protected against Denial-of-Service attacks, inactive connections and running out of ephemeral ports.

Note: By default, '--streaming-connection-idle-timeout' is set to 4 hours which might be too high for your environment. Setting this as appropriate would additionally ensure that such streaming connections are timed out after serving legitimate use cases.

Long-lived connections could be interrupted.

Remediation Method 1:

If modifying the Kubelet config file, edit the kubelet-config.json file '/etc/kubernetes/kubelet/kubelet-config.json' and set the below parameter to a non-zero value in the format of #h#m#s

"streamingConnectionIdleTimeout": "4h0m0s"

You should ensure that the kubelet service file '/etc/systemd/system/kubelet.service.d/10-kubelet-args.conf' does not specify a '--streaming-connection-idle-timeout' argument because it would override the Kubelet config file.

Remediation Method 2:

If using executable arguments, edit the kubelet service file '/etc/systemd/system/kubelet.service.d/10-kubelet-args.conf' on each worker node and add the below parameter at the end of the 'KUBELET_ARGS' variable string.

--streaming-connection-idle-timeout=4h0m0s

Remediation Method 3:

If using the api configz endpoint consider searching for the status of '"streamingConnectionIdleTimeout":' by extracting the live configuration from the nodes running kubelet.

**See detailed step-by-step configmap procedures in Reconfigure a Node's Kubelet in a Live Cluster, and then rerun the curl statement from audit process to check for kubelet configuration changes

kubectl proxy --port=8001 &

export HOSTNAME_PORT=localhost:8001 (example host and port number)
export NODE_NAME=ip-192.168.31.226.ec2.internal (example node name from "kubectl get nodes")

curl -sSL "http://${HOSTNAME_PORT}/api/v1/nodes/${NODE_NAME}/proxy/configz"

For all three remediations:
Based on your system, restart the 'kubelet' service and check status

systemctl daemon-reload
systemctl restart kubelet.service
systemctl status kubelet -l