K8s Notifier

A Python-based application for listening to a pubsub subscription for GKE cluster messages and sending notifications to slack.

GKE offers the option to send to a PubSub topic the following notification types:

• Version upgrade available (UpgradeAvailableEvent)
• Version upgrade started (UpgradeEvent)
• Security bulletin issued (SecurityBulletinEvent)

The aim of this tool is to provide a gke-notification-handler, which listen to a pubsub subscription and send notifications to a slack channel.

Read more details on GCP documentation.

Prerequisites

This is the list of prerequisites required for an existing GCP project:

• a PubSub topic and subscription
• a GKE cluster with Notifications feature enabled and declaring the Topic ID
• a Service Account with roles/pubsub.subscriber role to the subscription

You'll need also a Slack application with an incoming Webhook URL for the channel you'd like to receive these notifications. You can get more information at https://api.slack.com/messaging/webhooks.

How to use

Environment Variables

You will have to set the env variables below

Variable	Description
GCP_PROJECT_ID	The project ID on GCP
PUBSUB_SUBSCRIPTION_ID	The PubSub Subscription ID
SLACK_WEBHOOK_URL	The Webhook URL of the slack channel
GOOGLE_APPLICATION_CREDENTIALS	A credentials file path for the json key of Service Account
PUBSUB_TIMEOUT	Optionally set a timeout on subscription listening (in sec)

Try locally

For run - test locally set the vars in deploy.sh and run the following:

# run directly the python script by using the "app" as param
./deploy.sh app

# run locally as docker container by using an IMAGE_TAG value as param (this will build the image first)
deploy.sh IMAGE_TAG

Deploy on Kubernetes cluster

Use the following in order to deploy the application to a Kubernetes cluster:

# create a secret for the Service Account json key
kubectl create secret generic gcp-pubsub-sa-key --from-file=PATH_TO_GCP_PUBSUB_SA_KEY_FILE

# then update the environment variables and the image on deployment.yaml file and run the command:
kubectl apply -f deployment.yaml

Sample message from GKE

{
   data: 'Master is upgrading to version 1.23.8-gke.1900.'
   ordering_key: ''
   attributes: {
     "cluster_location": "us-east1",
     "cluster_name": "CLUSTER_NAME",
     "payload": "{\"resourceType\":\"MASTER\", \"operation\":\"operation-1662536672793-9f8f675f\", \"operationStartTime\":\"2022-09-07T07:44:32.793341429Z\", \"currentVersion\":\"1.23.7-gke.1400\", \"targetVersion\":\"1.23.8-gke.1900\"}",
     "project_id": "PROJECT_ID",
     "type_url": "type.googleapis.com/google.container.v1beta1.UpgradeEvent"
   }
}