node-sitter

node-sitter is a tool for implementing application fault tolerance in a node group with preemptible VMs.

The node-sitter features include:

• Pod eviction when cluster nodes on preemptible VMs shut down.
• Installation of additional trusted root certificates.
• Configuring container image downloads via a proxy.
• Advanced kubelet launch settings.

1. Configure the application:

   • Namespace: Create a new namespace, e.g., node-sitter. If you leave the default namespace, node-sitter may work incorrectly.
   • Application name: Specify the application name.
   • Install node-drainer: Leave this option enabled for the node-drainer script to prevent the Error or Completed pod states on the preemptible VM group nodes.
   • Tolerations key name: Specify the toleration key name. To enable node-sitter pods to configure new nodes before user load is distributed to them, specify a taint with the same key when creating or updating the node group with preemptible VMs. After the nodes are successfully configured, node-sitter will remove the taint policy so user applications can run on these nodes. If you skip this setting, the system will configure the nodes while starting user applications.
   • (Optional) Trusted certificates: Copy the contents of the PEM file with x.509 certificates to install them into the trusted certificate storage on the nodes of the preemptible VM group. When recreating nodes, the certificates will be reinstalled.
   • (Optional) Parameters for kubelet: Specify additional parameters for running kubelet on the nodes of the preemptible VM group.
   • (Optional) Proxy settings: Specify proxy settings for downloading container images on the nodes of the preemptible VM group. The settings are provided via the HTTP_PROXY and HTTPS_PROXY environment variables.
   • (Optional) Proxy exclusions: Specify a list of websites to access without a proxy. To provide the value, use the NO_PROXY environment variable.

2. Click Install.

3. Wait for the application to change its status to Deployed.

• Advanced setup of a node group with preemptible VMs in a Managed Kubernetes cluster.

Yandex Cloud technical support is available 24/7. The types of requests you can submit and the relevant response times depend on your pricing plan. You can switch to the paid support plan in the management console. You can learn more about the technical support terms and conditions here.