Mattermost Taint/Toleration Support

[runyontr]

Summary

The Mattermost Operator does not expose tolerations as part of the scheduling spec:

https://github.com/mattermost/mattermost-operator/blob/master/apis/mattermost/v1beta1/mattermost_types.go#L96

Steps to reproduce

Create Kubernetes nodes with a Taint and try and schedule the mattermost pods on those nodes.

Expected behavior

Given a taint, we should be able to tell the mattermost pods to tolerate the taint via:

apiVersion: installation.mattermost.com/v1beta1
kind: Mattermost
metadata:
  name: mattermost
  namespace: mattermost
spec:
  ... #omited for brevity
  scheduling:
    tolerations:
    - key: "key1"
      operator: "Equal"
      value: "value1"
      effect: "NoSchedule"

Observed behavior (that appears unintentional)

Possible fixes

1. Add toleration here: https://github.com/mattermost/mattermost-operator/blob/master/apis/mattermost/v1beta1/mattermost_types.go#L96

// Scheduling defines the configuration related to scheduling of the Mattermost pods
// as well as resource constraints.
type Scheduling struct {
	// Defines the resource requests and limits for the Mattermost app server pods.
	// +optional
	Resources v1.ResourceRequirements `json:"resources,omitempty"`
	// NodeSelector is a selector which must be true for the pod to fit on a node.
	// Selector which must match a node's labels for the pod to be scheduled on that node.
	// More info: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/
	// +optional
	NodeSelector map[string]string `json:"nodeSelector,omitempty"`
	// If specified, affinity will define the pod's scheduling constraints
	// +optional
	Affinity *v1.Affinity `json:"affinity,omitempty"`
        // +optional
        Tolerations *v1.Tolerations `json:"tolerations,omitempty"`
}

Toleration Spec

2. Pass tolerations into

   mattermost-operator/pkg/mattermost/mattermost.go

   Line 411 in 8df0b9e

   NodeSelector: mattermost.Spec.NodeSelector,

[Szymongib]

Hey, thanks for submitting the issue.

I think adding this could make sense and I really like the first solution proposed with a slight adjustment to keep it in line with PodSpec so that would be.

type Scheduling struct {
        ...
        Tolerations []v1.Toleration `json:"tolerations,omitempty"`
}

Marking it as a help wanted for now if anyone is willing to help on that.

[vineelyalamarthy]

@Szymongib is it up for grabs. What are other interesting problems to solve.

[gabrieljackson]

@vineelyalamarthy, yes this ticket is up for grabs if you want to take a shot at implementing it.

[vineelyalamarthy]

yes sure. @gabrieljackson would like to check out some tasks on the app backend as well. Any pointers.

[gabrieljackson]

Are you referring to the Mattermost App itself? If so, those help wanted tickets can be found here: https://github.com/mattermost/mattermost-server/issues?q=is%3Aopen+is%3Aissue+label%3A%22Up+For+Grabs%22

[vineelyalamarthy]

@gabrieljackson can you assign this to me.

[gabrieljackson]

@vineelyalamarthy Done! Thanks for taking this on.