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https://github.com/Ultimaker/k8s-mongo-operator

DEPRECATED - Kubernetes Operator for MongoDB Replica Sets and Backups.
https://github.com/Ultimaker/k8s-mongo-operator

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DEPRECATED - Kubernetes Operator for MongoDB Replica Sets and Backups.

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README 

        
# k8s-mongo-operator

MongoDB Operator for Kubernetes.



**This repository is no longer actively maintained. Please fork it and make the needed changes yourself.**



## Features

The following feature are currently available in this operator:



* Create, update or delete MongoDB replica sets.

* Automatically initialize the replica set configuration in the master node.

* Schedule backups to Google Cloud Storage using a Google service account and `mongodump`.



## Limitations

The current version has the limitations that shall be addressed in a later version:



- The watch API from Kubernetes is currently not being used, as we want to remain responsive for creating backups in case no events are received. This means:

  - We use list secret privilege to remove any admin operator secrets that are not used anymore. This is not part of the [best practices](https://kubernetes.io/docs/concepts/configuration/secret/#best-practices).

  - The solution is probably to listen to events with [`asyncio`](https://engineering.bitnami.com/articles/kubernetes-async-watches.html).

- Mongo instances are not using SSL certificates yet.



## Cluster interaction

Please refer to our [simplified diagram](./docs/architecture.png) to get an overview of the operator interactions with your Kubernetes cluster.



## Deployment

To deploy this operator in your own cluster, you'll need to create some configuration files.

An example of these configuration files can be found in [kubernetes/operators/mongo-operator](./kubernetes/operators/mongo-operator)



As you can see there is a service account (mongo-operator-service-account) which has some specific permissions in the cluster.

These permissions are registered in the cluster role and cluster role binding.



Lastly there is a deployment configuration to deploy the actual operator.

Usually you'd use an image value like `ultimaker/k8s-mongo-operator:master`, or a specific version.

All available tags can be found on [Docker Hub](https://hub.docker.com/r/ultimaker/k8s-mongo-operator/).



## Creating a Mongo object

To deploy a new replica set in your cluster using the operator, create a Kubernetes configuration file similar to this:



```yaml

apiVersion: "operators.ultimaker.com/v1"

kind: Mongo

metadata:

  name: mongo-cluster

spec:

  mongodb:

    replicas: 3

  backups:

    cron: "0 * * * *" # hourly

    gcs:

      bucket: "ultimaker-mongo-backups"

      serviceAccount:

        secretKeyRef:

          name: "storage-service-account"

          key: json

```



Then deploy it to the cluster like any other object:



```bash

kubectl apply -f mongo.yaml

```



### Configuration options

The following options are available to use in the `spec` section of the `yaml` configuration file. Keys with a `*` in front are required.



| Config key | Default | Description |

| --- | --- | --- |

| * `mongodb.mongo_name` | - | The name of the Mongo deployment. |

| `mongodb.storage_name` | mongo-storage | The name of the persistent volumes that Kubernetes will create and mount. |

| `mongodb.storage_size` | 30Gi | The size of the persistent volumes. |

| `mongodb.storage_data_path` | /data/db | The path on which the persistent volumes are mounted in the Mongo containers. |

| `mongodb.storage_class_name` | - | The name of the storage class to use to create the persistent values. If not passed it will use the Kubernetes cluster default storage class name. |

| `mongodb.cpu_limit` | 1 | The CPU limit of each container. |

| `mongodb.cpu_request` | 0.5 | The CPU request of each container. |

| `mongodb.memory_limit` | 2Gi | The memory limit of each container. |

| `mongodb.memory_request` | 1Gi | The memory request of each container. |

| `mongodb.wired_tiger_cache_size` | 0.25 | The wired tiger cache size. |

| `mongodb.replicas` | - | The amount of MongoDB replicas that should be available in the replica set. Must be an uneven positive integer and minimum 3. |

| * `backups.cron` | - | The cron on which to create a backup to cloud storage.

| * `backups.gcs.bucket` | - | The GCS bucket to upload the backup to. |

| `backups.gcs.restore_bucket` | - | The GCS bucket that contains the backup we wish to restore. If not specified, the value of backups.gcs.bucket is used. |

| `backups.gcs.restore_from` | - | Filename of the backup in the bucket we wish to restore. If not specified, or set to 'latest', the last backup created is used. |

| `backups.gcs.prefix` | backups/ | The file name prefix for the backup file. |



> Please read https://docs.mongodb.com/manual/administration/production-notes/#allocate-sufficient-ram-and-cpu for details about why setting the WiredTiger cache size is important when you change the container memory limit from the default value.



## Testing locally

To run the tests in a local Kubernetes (MiniKube) cluster, we have created a simple test script.



Ensure you have the following tools installed on your system:

- [Docker](https://store.docker.com/search?type=edition&offering=community)

- [MiniKube v0.25.2](https://github.com/kubernetes/minikube/releases/tag/v0.25.2) (please use this version specifically)



Then start a new MiniKube cluster using the following commands:



```bash

minikube start

```



Then you can run our test script to deploy the operator and execute some end-to-end tests.



Note that this script assumes there is a file `google-credentials.json` in this directory that will be uploaded to Kubernetes as the secret for the backups.

You will need to download this file from Google in order to run the script.



```bash

./build-and-deploy-local.sh

```



You will also see the operator logs streamed to your console.



## Contributing

Please make a GitHub issue or pull request to help us build this operator.



## Maintainance

The repo is currently maintained by Ultimaker. Contact us via the GitHub issues for questions or suggestions.