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How can I enable feature gates for my cluster in Rancher 2.0? I am in need of enabling the --feature-gates MountPropagation=true. This will enable me to use storage solutions like StorageOS, CephFS, etc

There are 2 use cases here :

  1. If the Rancher is setup already and running?
  2. If I am setting up the cluster from scratch?
damitj07
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3 Answers3

7

Hello and hope this helps someone, After much googling and help from awesome people at Rancher I got the solution for this. Here is what you can do to set the feature gates flags for the Kubernetes engine RKE.

step 1: Open Rancher2.0 UI

step 2: View cluster in API

enter image description here

step 3: Click edit and modify the rancherKubernetesEngineConfig input box

enter image description here

  • Find the services key.

  • Then add extra args for kubelet in below format

    "services": {
"etcd": { "type": "/v3/schemas/etcdService" },
"kubeApi": {
    "podSecurityPolicy": false,
    "type": "/v3/schemas/kubeAPIService",
    "extraArgs": { "feature-gates": "PersistentLocalVolumes=true, VolumeScheduling=true,MountPropagation=true" }
},
"kubeController": { "type": "/v3/schemas/kubeControllerService" },
"kubelet": {
    "failSwapOn": false,
    "type": "/v3/schemas/kubeletService",
    "extraArgs": { "feature-gates": "PersistentLocalVolumes=true, VolumeScheduling=true,MountPropagation=true" }
}

step 4: Click show request .. you get a curl command and json request.

step 5: Verify the request body data which will be shown.

step 6: Make sure the key's which are not applicable are set to null. e.g amazonElasticContainerServiceConfig, azureKubernetesServiceConfig, googleKubernetesEngineConfig all need to null for me.

step 7: Click send request

You should get a response with status code 201. And your cluster will start updating. You can verify that your cluster RKE has updated by viewing the Cluster in API again.

damitj07
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3

I was strugling with enabling feature gate TTLAfterFinished. (same as MountPropagation=true)

Rancher v2.3.3

step 1: Open Rancher2.3.3 UI

step 2: Click edit cluster

step 3: Click the button "edit as YAML" next to "Cluster Options"

step 4: You need to add feature gate to all cluster services (see below)

step 5: add or edit extra_args similar to this:

    ...
        kube-api:
          extra_args:
            feature-gates: TTLAfterFinished=true
    ...
        kube-controller:
          extra_args:
            feature-gates: TTLAfterFinished=true
    ...
        kubelet:
          extra_args:
            feature-gates: TTLAfterFinished=true
    ...

Replace TTLAfterFinished with your feature gate. LIST HERE

Petr
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1

alternative (test is pending, blocked by https://github.com/rancher/rancher/issues/26261):

step 1: Open Rancher2.0 UI

step 2: Click edit for cluster (in menu with three vertical dots)

step 3: Click the button "edit as YAML" next to "Cluster Options"

step 4: find "services.kubelet" (or "services.WhatYouNeed")

step 5: add or edit extra_args similar to this:

    kubelet:
      extra_args:
        feature-gates: rancherKubernetesEngineConfig=true

(according to https://rancher.com/docs/rke/latest/en/config-options/services/services-extras/#extra-args)

step 6: click save (at bottom)

create new cluster

You can also edit "Cluster Options" as yaml when creating a new cluster. Probably this can also be included as an "rke template".

simohe
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