k8s-oom-monitor

Monitor that alerts to Slack when a Kubernetes pod is killed with OutOfMemory (OOM).

This Go application has less than 150 lines of code but provides a critical monitoring feature for our infrastructure.

Install

1. Go to Your Slack Apps and create a new one. You can use any name you want and select the workspace you will use to receive the messages.

2. In the sidebar visit the Incoming Webhooks section and enable it with the switch On/Off in the top-right of the screen.

3. In the same sidebar move to Install App and install the application in your workspace. It will ask for permissions and you can select the destination channel.

4. Copy the Webhook URL for Your Workspace when you return to the install page after succesfully authorizing the new application.

5. Save the example deployment configuration to k8s-oom-monitor.yaml replacing the URL of SLACK_WEBHOOK with the webhook URL you copied in step 4. You have a copy as a standalone file here.

   apiVersion: v1
   kind: ServiceAccount
   metadata:
     name: k8s-oom-monitor
   ---
   apiVersion: rbac.authorization.k8s.io/v1beta1
   kind: ClusterRole
   metadata:
     name: k8s-oom-monitor
   rules:
   - apiGroups: ['']
     resources:
     - events
     verbs:
     - watch
   ---
   apiVersion: rbac.authorization.k8s.io/v1beta1
   kind: RoleBinding
   metadata:
     name: k8s-oom-monitor
   subjects:
   - kind: ServiceAccount
     name: k8s-oom-monitor
   roleRef:
     kind: ClusterRole
     name: k8s-oom-monitor
     apiGroup: rbac.authorization.k8s.io
   ---
   apiVersion: extensions/v1beta1
   kind: Deployment
   metadata:
     name: k8s-oom-monitor
   spec:
     replicas: 1
     revisionHistoryLimit: 10
     strategy:
       rollingUpdate:
         maxUnavailable: 0
     template:
       metadata:
         labels:
           app: k8s-oom-monitor
       spec:
         serviceAccount: k8s-oom-monitor
         containers:
         - name: k8s-oom-monitor
           image: altipla/k8s-oom-monitor:v1.0.2
           env:
           - name: SLACK_WEBHOOK
             value: https://REPLACE_URL/WITH_THE_REAL_ONE
           resources:
             requests:
               cpu: 10m
               memory: 50Mi
             limits:
               memory: 50Mi

6. If you are working with GKE (Google Kubernetes Engine) you will need to authorize your own account to have admin permissions to be able to create the ClusterRole the app needs. You can configure the permissions with the following command:

   kubectl create clusterrolebinding cluster-admin-binding \
     --clusterrole cluster-admin --user $(gcloud config get-value account)

7. Deploy the file to the Kubernetes cluster you want to monitorize: kubectl apply -f k8s-oom-monitor.yaml

Uninstall

To remove the application and all the authorizations it creates in the install tutorial use the following commands:

kubectl delete deployment k8s-oom-monitor
kubectl delete clusterrole k8s-oom-monitor
kubectl delete rolebinding k8s-oom-monitor
kubectl delete serviceaccount k8s-oom-monitor

Contributing

You can make pull requests or create issues in GitHub. Any code you send should be formatted using gofmt

License

MIT License