feat(nbd-client/multi): allow partial connexion

@vates/nbd-client/multi.mjs

@@ -1,7 +1,9 @@
 import { asyncEach } from '@vates/async-each'
 import { NBD_DEFAULT_BLOCK_SIZE } from './constants.mjs'
 import NbdClient from './index.mjs'
+import { createLogger } from '@xen-orchestra/log'
 
+const { warn } = createLogger('vates:nbd-client:multi')
 export default class MultiNbdClient {
   #clients = []
   #readAhead
@@ -19,8 +21,25 @@ export default class MultiNbdClient {
   }
 
   async connect() {
-    for (const client of this.#clients) {
-      await client.connect()
+    const connectedClients = []
+    for (const clientId in this.#clients) {
+      const client = this.#clients[clientId]
+      try {
+        await client.connect()
+        connectedClients.push(client)
+      } catch (err) {
+        client.disconnect().catch(() => {})
+        warn(`can't connect to one nbd client`, { err })
+      }
+    }
+    if (connectedClients.length === 0) {
+      throw new Error(`Fail to connect to any Nbd client`)
+    }
+    if (connectedClients.length < this.#clients.length) {
+      warn(
+        `incomplete connection by multi Nbd, only ${connectedClients.length} over ${this.#clients.length} expected clients`
+      )
+      this.#clients = connectedClients
     }
   }
 

@xen-orchestra/backups/_runners/_vmRunners/IncrementalXapi.mjs

@@ -41,8 +41,8 @@ export const IncrementalXapi = class IncrementalXapiVmBackupRunner extends Abstr
 
     const deltaExport = await exportIncrementalVm(exportedVm, baseVm, {
       fullVdisRequired,
-      preferNbd: this._settings.preferNbd,
       nbdConcurrency: this._settings.nbdConcurrency,
+      preferNbd: this._settings.preferNbd,
     })
     // since NBD is network based, if one disk use nbd , all the disk use them
     // except the suspended VDI

packages/xo-server/src/api/backup-ng.mjs

@@ -22,15 +22,15 @@ const SCHEMA_SETTINGS = {
           minimum: 0,
           optional: true,
         },
-        preferNbd: {
-          type: 'boolean',
-          optional: true,
-        },
         nbdConcurrency: {
           type: 'number',
           minimum: 1,
           optional: true,
         },
+        preferNbd: {
+          type: 'boolean',
+          optional: true,
+        },
       },
       additionalProperties: true,
     },