From 0462d79ef7933dcfd19b67b1b6056dcf47a4a394 Mon Sep 17 00:00:00 2001
From: Simon Croome <simon.croome@storageos.com>
Date: Wed, 18 Mar 2020 12:52:18 +0000
Subject: [PATCH] Pass cluster node selector to NFS pods (#236)

* Inherit NFS server node selectors from cluster
---
 README.md              |  2 +-
 pkg/nfs/statefulset.go |  7 ++++++-
 pkg/util/podspec.go    | 14 ++++++++++++++
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/README.md b/README.md
index 4daad761f..d618ba319 100644
--- a/README.md
+++ b/README.md
@@ -144,7 +144,7 @@ Parameter | Description | Default
 `disableTCMU` | Disable TCMU to allow co-existence with other storage systems but degrades performance | `false`
 `forceTCMU` | Forces TCMU to be enabled or causes StorageOS to abort startup | `false`
 `disableScheduler` | Disable StorageOS scheduler for data locality | `false`
-`nodeSelectorTerms` | Set node selector for storageos pod placement |
+`nodeSelectorTerms` | Set node selector for storageos pod placement, including NFS pods |
 `tolerations` | Set pod tolerations for storageos pod placement |
 `resources` | Set resource requirements for the containers |
 `k8sDistro` | The name of the Kubernetes distribution is use, e.g. `rancher` or `eks` |
diff --git a/pkg/nfs/statefulset.go b/pkg/nfs/statefulset.go
index c379d6436..fd87a2ef9 100644
--- a/pkg/nfs/statefulset.go
+++ b/pkg/nfs/statefulset.go
@@ -35,9 +35,14 @@ func (d *Deployment) createStatefulSet(pvcVS *corev1.PersistentVolumeClaimVolume
 	}
 	spec.Template.Spec.Volumes = append(spec.Template.Spec.Volumes, vol)
 
-	// TODO: Add node affinity support for NFS server pods.
 	util.AddTolerations(&spec.Template.Spec, d.nfsServer.Spec.Tolerations)
 
+	// If the cluster was configured with node selectors to only run on certain
+	// nodes, use the same selectors to selct the nodes that the NFS pods can
+	// run on.  NFSServer does not currently allow setting node selectors or
+	// affinity directly.
+	util.AddRequiredNodeAffinity(&spec.Template.Spec, d.cluster.Spec.NodeSelectorTerms)
+
 	return d.k8sResourceManager.StatefulSet(d.nfsServer.Name, d.nfsServer.Namespace, nil, spec).Create()
 }
 
diff --git a/pkg/util/podspec.go b/pkg/util/podspec.go
index 12e763e84..f4aa1bf97 100644
--- a/pkg/util/podspec.go
+++ b/pkg/util/podspec.go
@@ -18,3 +18,17 @@ func AddTolerations(podSpec *corev1.PodSpec, tolerations []corev1.Toleration) er
 	}
 	return nil
 }
+
+// AddRequiredNodeAffinity adds required node affinity to the given pod spec.
+func AddRequiredNodeAffinity(podSpec *corev1.PodSpec, terms []corev1.NodeSelectorTerm) {
+	if len(terms) == 0 {
+		return
+	}
+	podSpec.Affinity = &corev1.Affinity{
+		NodeAffinity: &corev1.NodeAffinity{
+			RequiredDuringSchedulingIgnoredDuringExecution: &corev1.NodeSelector{
+				NodeSelectorTerms: terms,
+			},
+		},
+	}
+}