mailu-operator

The purpose of this project is to define Email Domains, Users and Aliases used in Mailu via CRs.

The Mailu-Operator uses the Mailu API to create/update/delete Domains, Users and Aliases, it therefore needs the API endpoint and token which can be set through command line or the environment variables MAILU_SERVER and MAILU_TOKEN.

Important note: A user can still make changes in the Mailu frontend which are not synced back to the CRDs. Also, some changes may be intended to be done "on-the-fly" in the Mailu frontend, for example setting auto reply or changing the password.

Description

This operator adds three custom resources: Domain, User and Alias and each resource represents an object in Mailu API. For details refer also to your Mailu API documentation: https://mailu.io/master/api.html

Domain fields and defaults (see sample)

• Name (required)
• Comment
• MaxUsers = 0
• MaxAliases = 0
• MaxQuotaBytes = 0
• SignupEnabled = false
• Alternatives

User fields and defaults (see sample)

• Name (required)
• Domain (required)
• AllowSpoofing = false
• ChangePwNextLogin = true
• Comment
• DisplayedName
• Enabled = false
• EnableImap = true
• EnablePop = true
• ForwardDestination
• ForwardEnabled = false
• ForwardKeep = false
• GlobalAdmin = false
• Password (hash, excluded from updates)
• PasswordSecret (takes precedence over RawPassword, secret name in the current namespace)
• PasswordKey (key within the PasswordSecret which contains the password)
• QuotaBytes = 0
• QuotaBytesUsed (excluded from updates)
• RawPassword (excluded from updates; optional: if not set, a random password will be generated)
• ReplyBody (TODO: excluded from updates)
• ReplyEnabled = false (TODO: excluded from updates)
• ReplyEnddate (TODO: excluded from updates)
• ReplyStartdate (TODO: excluded from updates)
• ReplySubject (TODO: excluded from updates)
• SpamEnabled = false
• SpamMarkAsRead = false
• SpamThreshold

Alias fields and defaults (see sample)

• Name (required)
• Domain (required)
• Comment
• Destination
• Wildcard = false

Simplified flow

Using Domain as an example resource

flowchart LR
  CRD(Domain resource)
  Controller
  MailuAPI(Mailu API)
  
  User -- 1. create/update/delete Domain resource --> CRD
  
  Controller -- 2. watch Domain resources --> CRD
  Controller -- 3. get/create/update/delete Domain --> MailuAPI
  Controller -- 4. update resource status --> CRD

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How to use the resources

Domain

Domains defines the domain names known to the mail system.

At the current state, this project does not touch DNS records in any form, nor does it trigger generation of DKIM keys. It might be interesting to automate DNS records in the future with external-dns: Mailu/Mailu#547 (comment)

User

Basically any email address that should be able to receive or send emails on its address must be a user. The domain used must be configured. Even if you only forward emails to an external address hosted elsewhere, you need to create a user (with forwardDestination set).

Alias

Aliases only work with domains and email addresses know to the system, i.e. you cannot define an alias to forward emails to an external address. For that, you need to create a user.

Aliases are used to route emails for multiple email addresses to a user (email) known to the system.

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.
• A running installation of Mailu with API enabled.

Try it out

As this project is brand new and in alpha stage, here are the current steps to try it out:

1. get and apply the install.yaml which contains the CRDs and the deployment of the operator.
2. edit the deployment to configure MAILU_API and MAILU_TOKEN environment variables.
3. create Domain, User and Alias resources that will be applied to your Mailu instance.

LATEST=https://raw.githubusercontent.com/SickHub/mailu-operator/main/dist/install.yaml
RELEASE=https://raw.githubusercontent.com/SickHub/mailu-operator/v0.0.2/dist/install.yaml
NAMESPACE=mailu
kubectl apply -n $NAMESPACE -f $RELEASE

# edit the deployment and set your Mailu API url and token
kubectl -n $NAMESPACE edit deployment mailu-operator-controller-manager

# now you can add Domain, User and Alias resources
kubectl apply -n $NAMESPACE -f config/samples/operator_v1alpha1_domain.yaml
kubectl apply -n $NAMESPACE -f config/samples/operator_v1alpha1_user.yaml
kubectl apply -n $NAMESPACE -f config/samples/operator_v1alpha1_alias.yaml

# remove the operator again
kubectl delete -n $NAMESPACE -f $RELEASE

Build and install the operator from your fork:

REGISTRY=<your-registry>
NAMESPACE=mailu
# 1. build the image and push it to your own registry
make docker-buildx IMG=$REGISTRY/mailu-operator:dev

# 2. build the `install.yaml` used to deploy the operator (including CRDs, Roles and Deployment)
make build-installer IMG=$REGISTRY/mailu-operator:dev

# 3. apply the `install.yaml` to your k8s cluster
kubectl apply -n $NAMESPACE -f dist/install.yaml

# 4. edit the `MAILU_API` and `MAILU_TOKEN` environment variables
kubectl -n $NAMESPACE edit deployment mailu-operator-controller-manager

Uninstall the operator

kubectl delete -n $NAMESPACE -f dist/install.yaml

Development: Build and deploy on your cluster

To setup the project, operator-sdk was used to generate the structure and custom resource objects:

operator-sdk init --plugins=go/v4 --domain mailu.io --repo github.com/sickhub/mailu-operator
operator-sdk create api --group operator --version v1alpha1 --kind Domain --resource --controller
operator-sdk create api --group operator --version v1alpha1 --kind User --resource --controller
operator-sdk create api --group operator --version v1alpha1 --kind Alias --resource --controller

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

make docker-build docker-push IMG=<some-registry>/mailu-operator: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>/mailu-operator: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

Releasing / Project Distribution

Following are the steps to build the installer and distribute this project to users. It is generally advised to create a fork of the repo and create Pull-Requests from your fork.

1. Build the installer for the release tag:

   git checkout -b release-0.0.2
   VERSION=0.0.2 make build-installer

2. Create a Pull-Request on GitHub with the changes

   • at least dist/install.yaml and config/manager/kustomization.yaml containing the latest tag

3. Get the Pull-Request reviewed/approved and merged

   • the image will be built and pushed to docker hub
   • a release with be created with generated release notes

4. Push the tag

   git checkout main
   git tag v0.0.2
   git push

Contributing

// TODO(user): Add detailed information on how you would like others to contribute to this project

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

More information can be found via the Kubebuilder Documentation