conclusionlogic/node-affinity-guard repository overview

⁠node-affinity-guard

node-affinity-guard is a Kubernetes utility designed to ensure that a specific StatefulSet or Deployment is running on the same node as a given floating IP (VIP).

It manages node labels for node affinity rules to maintain the desired state within the cluster.

⁠Features

• Monitors the presence of a specified VIP in the cluster.
• Ensures that a specified StatefulSet or Deployment is running on the same node as the VIP.
• Manages node labels to facilitate the correct placement of workloads using node affinity rules.
• Configurable logging levels for easy debugging and monitoring.

⁠Prerequisites

• Kubernetes cluster
• Appropriate permissions to interact with the Kubernetes API

⁠Installation

1. Clone the repository:

   git clone https://github.com/conclusionlogic/node-affinity-guard.git
   cd node-affinity-guard
   

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2. Build the binary:

   go build -o node-affinity-guard main.go
   

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   or with Docker:

   docker build .
   

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3. Set up the required environment variables:

   export HOSTNAME=<your-node-hostname>
   export CHECK_INTERVAL=<interval-duration>
   export IP_ADDRESS=<floating-ip-address>
   export NODE_LABEL_KEY=<node-label-key>
   export NODE_LABEL_VALUE_ACTIVE=<node-label-active-value>
   export NODE_LABEL_VALUE_INACTIVE=<node-label-inactive-value>
   export LOG_LEVEL=<log-level>  # Options: debug, info, warn, error
   

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⁠Usage

Run the node-affinity-guard binary:

./node-affinity-guard

The program will start monitoring the specified VIP and managing the node labels to ensure that the StatefulSet or Deployment is running on the same node as the VIP.

⁠Configuration

• HOSTNAME: The hostname of the node to monitor.
• CHECK_INTERVAL: The interval at which to check the presence of the VIP (e.g., "30s", "5m").
• IP_ADDRESS: The floating IP address to monitor.
• NODE_LABEL_KEY: The key of the node label to manage.
• NODE_LABEL_VALUE_ACTIVE: The value of the node label when the VIP is present on the node.
• NODE_LABEL_VALUE_INACTIVE: The value of the node label when the VIP is not present on the node.
• LOG_LEVEL: The level of logging detail (options: debug, info, warn, error).

⁠Using the node-affinity-guard Helm Chart

This repository contains the Helm chart for deploying the node-affinity-guard. Follow the steps below to add the Helm repository and deploy the chart.

⁠Helm Chart prerequisites

• Helm installed
• Kubernetes cluster

⁠Adding the Helm Repository

1. Add the Helm repository:

   helm repo add node-affinity-guard https://conclusionlogic.github.io/node-affinity-guard/
   

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2. Update the Helm repository to ensure you have the latest version of the chart:

   helm repo update
   

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⁠Deploying the Chart

1. Install the node-affinity-guard chart with a release name of your choice (e.g., my-release):

   helm install my-release node-affinity-guard/node-affinity-guard
   

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2. To customize the deployment, you can pass custom values via the --set flag or provide a values.yaml file. For example:

   helm install my-release node-affinity-guard/node-affinity-guard --set hostname=node-1,checkInterval=1m,ipAddress=192.168.1.100,nodeLabelKey=vip-active,nodeLabelValueActive=true,nodeLabelValueInactive=false,logLevel=info
   

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⁠Upgrading the Chart

To upgrade the chart to a new version:

helm upgrade my-release node-affinity-guard/node-affinity-guard

⁠Uninstalling the Chart

To uninstall the deployed release:

helm uninstall my-release

⁠Values

The following table lists the configurable parameters of the node-affinity-guard chart and their default values.

⁠Example

To deploy the node-affinity-guard with specific values:

helm install my-release node-affinity-guard/node-affinity-guard --set hostname=node-1,checkInterval=1m,ipAddress=192.168.1.100,nodeLabelKey=vip-active,nodeLabelValueActive=true,nodeLabelValueInactive=false,logLevel=info

For more details, refer to the Helm documentation⁠.

⁠Contributing

Contributions are welcome! Please submit a pull request or open an issue to discuss any changes.

⁠License

This project is licensed under the MIT License. See the LICENSE⁠ file for details.