broom is a Kubernetes Custom Controller designed to gracefully handle Out of Memory (OOM) events in CronJobs by dynamically increasing memory limits.

It offers the following features:

• Dynamic Memory Limit Adjustment: Automatically increases the memory limit of containers that experience OOM events within CronJob specs.

• Flexible Memory Adjustment Methods: Users can choose between addition and multiplication methods for increasing memory limits.

• Automatic Job Restart: Optionally, broom can restart the failed jobs with updated spec for recovery.

• Flexible Targeting: Allows specifying target CronJobs using combinations of Name, Namespace, and Labels.

• Slack Notification Integration: Provides webhook notifications to Slack, informing users about the results of updates and restarts.

Description

How it works

When a phase: Failed Pod is detected, the reconciliation loop iterates as follows:

Upon identifying a Pod terminated due to reason: OOMKilled, the controller traces back through the ownerReferences from Pod to Job to CronJob. Once the controller identifies the relevant CronJob, it prepares a modified specification with relaxed memory limits (spec.jobTemplate.spec.containers[].resources.limits.memory), such as doubling the original limit. Subsequently, the controller updates the specification of the CronJob with the modified memory limits. Optionally, the controller can restart the failed Job once using the updated memory limits. Finally, the controller sends a notification to Slack with the following content:

Configuration

The controller can be configured using a Broom custom resource, which allows users to specify the following parameters:

apiVersion: ai.m3.com/v1alpha1
kind: Broom
metadata:
  name: broom-sample
spec:
  target:
    name: oom-sample
    labels:
      m3.com/use-broom: "true"
    namespace: broom
  adjustment:
    type: Mul
    value: "2"
    maxLimit: 250Mi
  restartPolicy: OnSpecChanged
  slackWebhook:
    secret:
      namespace: default
      name: broom
      key: SLACK_WEBHOOK_URL
    channel: "#alert"

• target (optional) : Target CronJob conditions. If not specified, the controller will target all CronJobs in the cluster.

  • namespace (optional) : Namespace of the target CronJob.
  • name (optional) : Name of the target CronJob.
  • labels (optional) : Labels to filter the target CronJobs.

• adjustment (required) : Memory limit adjustment parameters.

  • type (required) : Adjustment method. Choose between Add and Mul.
  • value (required) : Adjustment value. For Add, it is the value to add to the current limit (e.g., 100Mi). For Mul, it is the multiplier to apply to the current limit (e.g., "2", must be double-quoted).
  • maxLimit (optional) : Maximum memory limit to set.

• restartPolicy (required) : Policy for restarting failed Jobs. Choose among Never (no restart), OnOOM (restart when OOM CronJob is detected), and OnSpecChanged (restart only when OOM CronJob is detected and the memory limit is updated).

• slackWebhook (required) : Slack notification integration.

  • secret (required) : Kubernetes Secret containing the Slack webhook URL.
    • namespace (required) : Namespace of the Secret.
    • name (required) : Name of the Secret.
    • key (required) : Key containing the webhook URL.
  • channel (optional) : Slack channel to send notifications. If not specified, the notification will be sent to the default channel.

Getting Started

Prerequisites

• go version v1.21.0+
• docker version 17.03+.
• kubectl version v1.11.3+.
• Access to a Kubernetes v1.11.3+ cluster.

To Deploy on the cluster

Build and push your image to the location specified by IMG:

make docker-build docker-push IMG=<some-registry>/broom:tag

NOTE: This image ought to be published in the personal registry you specified. And it is required to have access to pull the image from the working environment. Make sure you have the proper permission to the registry if the above commands don’t work.

Install the CRDs into the cluster:

make install

Deploy the Manager to the cluster with the image specified by IMG:

make deploy IMG=<some-registry>/broom:tag

NOTE: If you encounter RBAC errors, you may need to grant yourself cluster-admin privileges or be logged in as admin.

Create instances of your solution You can apply the samples (examples) from the config/sample:

kubectl apply -k config/samples/

NOTE: Ensure that the samples has default values to test it out.

To Uninstall

Delete the instances (CRs) from the cluster:

kubectl delete -k config/samples/

Delete the APIs(CRDs) from the cluster:

make uninstall

UnDeploy the controller from the cluster:

make undeploy

Project Distribution

Following are the steps to build the installer and distribute this project to users.

1. Build the installer for the image built and published in the registry:

make build-installer IMG=<some-registry>/broom:tag

NOTE: The makefile target mentioned above generates an 'install.yaml' file in the dist directory. This file contains all the resources built with Kustomize, which are necessary to install this project without its dependencies.

2. Using the installer

Users can just run kubectl apply -f to install the project, i.e.:

kubectl apply -f https://raw.githubusercontent.com/<org>/broom/<tag or branch>/dist/install.yaml
# kubectl apply -f https://raw.githubusercontent.com/m3dev/broom/main/dist/install.yaml

NOTE: Run make help for more information on all potential make targets

More information can be found via the Kubebuilder Documentation

Contributing

We welcome contributions from the community! If you'd like to contribute to this project, please follow these guidelines:

Issues

If you encounter a bug, have a feature request, or would like to suggest an improvement, please open an issue on the GitHub repository. Make sure to provide detailed information about the problem or suggestion.

Pull Requests

We gladly accept pull requests! Before submitting a pull request, please ensure the following:

1. Fork the repository and create your branch from main.
2. Ensure your code adheres to the project's coding standards.
3. Test your changes thoroughly.
4. Make sure your commits are descriptive and well-documented.
5. Update the README and any relevant documentation if necessary.

Code of Conduct

Please note that this project is governed by our Code of Conduct. By participating, you are expected to uphold this code. Please report any unacceptable behavior.

Thank you for contributing to our project!

License

Copyright 2024.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.