test/nfs: Add new test for NFS client on fcos

Sets up a single VM with NFS server running as container.

Clients mounts the same export under different mouthpaths for
NFS versions 3 and 4, and checks existence of a tempfile

This test is added in relation with with the following issue:
coreos/fedora-coreos-tracker#1942

Author: PeaceRebel

mantle/kola/tests/misc/nfs-client.go

@@ -0,0 +1,163 @@
+// Copyright 2025 Red Hat, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package misc
+
+import (
+	"fmt"
+	"path"
+	"time"
+
+	"github.com/coreos/coreos-assembler/mantle/kola"
+	"github.com/coreos/coreos-assembler/mantle/kola/cluster"
+	"github.com/coreos/coreos-assembler/mantle/kola/register"
+	"github.com/coreos/coreos-assembler/mantle/platform/conf"
+	"github.com/coreos/coreos-assembler/mantle/util"
+)
+
+const (
+	machine_conf = `
+variant: fcos
+version: 1.5.0
+storage:
+  files:
+    - path: /etc/containers/systemd/nfs.container
+      overwrite: true
+      contents:
+        inline: |
+          [Container]
+          Image=quay.io/coreos-assembler/nfs
+          Volume=/tmp:/export
+          Network=host
+          PodmanArgs=--privileged
+          [Install]
+          WantedBy=default.target
+    - path: "/etc/hostname"
+      contents:
+        inline: "nfs-client"
+      mode: 0644
+systemd:
+  units:
+    - name: "var-mnt-nfsv4.mount"
+      enabled: true
+      contents: |-
+        [Unit]
+        Description=NFS Client
+        After=network-online.target
+        Requires=network-online.target
+        After=rpc-statd.service nfs.service
+        Requires=rpc-statd.service
+
+        [Mount]
+        What=127.0.0.1:/
+        Where=/var/mnt/nfsv4
+        Type=nfs4
+        Options=defaults,noexec,nfsvers=4
+
+        [Install]
+        WantedBy=multi-user.target
+    - name: "var-mnt-nfs.mount"
+      enabled: true
+      contents: |-
+        [Unit]
+        Description=NFS Client
+        After=network-online.target
+        Requires=network-online.target
+        After=rpc-statd.service nfs.service
+        Requires=rpc-statd.service
+
+        [Mount]
+        What=127.0.0.1:/export
+        Where=/var/mnt/nfs
+        Type=nfs
+        Options=vers=3
+
+        [Install]
+        WantedBy=multi-user.target`
+)
+
+// Test nfs client
+
+func init() {
+	register.RegisterTest(&register.Test{
+		Run:         nfsClientTest,
+		ClusterSize: 1,
+		UserData:    conf.Butane(machine_conf),
+		Name:        "linux.nfs.client",
+		Description: "Verifies NFS client works.",
+		Tags:        []string{kola.NeedsInternetTag},
+		Platforms:   []string{"qemu"},
+
+		// RHCOS has a separate test for NFS v4 server and client
+		ExcludeDistros: []string{"rhcos"},
+	})
+}
+
+func nfsClientTest(c cluster.TestCluster) {
+
+	nfs_machine := c.Machines()[0]
+
+	// Wait for nfs server to become active
+	// 1 minutes should be enough to pull the container image
+	err := util.Retry(4, 15*time.Second, func() error {
+
+		nfs_status, err := c.SSH(nfs_machine, "systemctl is-active nfs.service")
+
+		if err != nil {
+			return err
+		} else if string(nfs_status) == "inactive" {
+			return fmt.Errorf("nfs.service is not ready: %s.", string(nfs_status))
+		}
+		return nil
+	})
+	if err != nil {
+		c.Fatalf("Timed out while waiting for nfs.service to be ready: %v", err)
+	}
+
+	c.Log("NFS server booted")
+
+	// poke a file in /tmp
+	tmp := c.MustSSH(nfs_machine, "mktemp")
+
+	checkv4mount := func() error {
+		status, err := c.SSH(nfs_machine, "systemctl is-active var-mnt-nfsv4.mount")
+		if err != nil || string(status) != "active" {
+			return fmt.Errorf("var-mnt-nfsv4.mount status is %q: %v", status, err)
+		}
+
+		c.Log("Got NFSv4 mount.")
+		return nil
+	}
+
+	if err = util.Retry(10, 3*time.Second, checkv4mount); err != nil {
+		c.Fatal(err)
+	}
+
+	checkmount := func() error {
+		status, err := c.SSH(nfs_machine, "systemctl is-active var-mnt-nfs.mount")
+		if err != nil || string(status) != "active" {
+			return fmt.Errorf("var-mnt-nfs.mount status is %q: %v", status, err)
+		}
+
+		c.Log("Got NFSv3 mount.")
+		return nil
+	}
+
+	if err = util.Retry(10, 3*time.Second, checkmount); err != nil {
+		c.Fatal(err)
+	}
+
+	c.RunCmdSyncf(nfs_machine, "stat /var/mnt/nfsv4/%s", path.Base(string(tmp)))
+	c.RunCmdSyncf(nfs_machine, "stat /var/mnt/nfs/%s", path.Base(string(tmp)))
+}