[lxc-devel] [lxd/master] VM: Adds cephfs disk support

[tomponline on Github]

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From ccc072d6d8e8880f7af3ffb1305b94f6940fdeb6 Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Mon, 20 Apr 2020 10:36:07 +0100
Subject: [PATCH 1/2] lxd/devoce/device/utils/disk: Comment on
 diskCephfsOptions

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 lxd/device/device_utils_disk.go | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lxd/device/device_utils_disk.go b/lxd/device/device_utils_disk.go
index 8490bb144f..9047d62446 100644
--- a/lxd/device/device_utils_disk.go
+++ b/lxd/device/device_utils_disk.go
@@ -245,6 +245,7 @@ func cephFsConfig(clusterName string, userName string) ([]string, string, error)
 	return cephMon, cephSecret, nil
 }
 
+// diskCephfsOptions returns the mntSrcPath and fsOptions to use for mounting a cephfs share.
 func diskCephfsOptions(clusterName string, userName string, fsName string, fsPath string) (string, string, error) {
 	// Get the credentials and host
 	monAddresses, secret, err := cephFsConfig(clusterName, userName)

From 6ad54f8e56bc4583cd861c6cbf80272b2b1872c3 Mon Sep 17 00:00:00 2001
From: Thomas Parrott <thomas.parrott at canonical.com>
Date: Mon, 20 Apr 2020 10:36:37 +0100
Subject: [PATCH 2/2] lxd/device/disk: Adds cephfs support for VMs

Fixes #7184

Signed-off-by: Thomas Parrott <thomas.parrott at canonical.com>
---
 lxd/device/disk.go | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/lxd/device/disk.go b/lxd/device/disk.go
index 3e25b09ffb..39a4ec9401 100644
--- a/lxd/device/disk.go
+++ b/lxd/device/disk.go
@@ -426,10 +426,10 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 			}
 		} else {
 			srcPath := shared.HostPath(d.config["source"])
+			var err error
 
 			// Mount the pool volume and update srcPath to mount path.
 			if d.config["pool"] != "" {
-				var err error
 				srcPath, err = d.mountPoolVolume(revert)
 				if err != nil {
 					if !isRequired {
@@ -439,6 +439,13 @@ func (d *disk) startVM() (*deviceConfig.RunConfig, error) {
 						return nil, err
 					}
 				}
+			} else if strings.HasPrefix(d.config["source"], "cephfs:") {
+				// Mount the cephfs directory on the host and then treat as a normal directory to
+				// share with the VM using 9p below.
+				srcPath, err = d.createDevice()
+				if err != nil {
+					return nil, err
+				}
 			}
 
 			if !shared.PathExists(srcPath) {
@@ -1139,8 +1146,8 @@ func (d *disk) postStop() error {
 	// Clean any existing entry.
 	if shared.PathExists(devPath) {
 		// Unmount the host side if not already.
-		// Don't check for errors here as this is just to catch any existing mounts that
-		// we not unmounted on the host after device was started.
+		// Don't check for errors here as this is just to catch any existing mounts that we have not
+		// unmounted on the host after device was started (such as when using cephfs with VM 9p share).
 		unix.Unmount(devPath, unix.MNT_DETACH)
 
 		// Remove the host side.