THM-Health · samuelwei · Jul 15, 2026
diff --git a/app/Http/Controllers/api/v1/ServerPoolController.php b/app/Http/Controllers/api/v1/ServerPoolController.php
@@ -34,11 +34,12 @@ public function __construct()
     public function index(ServerPoolIndexRequest $request)
     {
         $additionalMeta = [];
-        $resource = ServerPool::withCount('servers');
+        $resource = ServerPool::withCount(['servers', 'backupServers']);
 
         // Sort by column, fallback/default is id
         $sortBy = match ($request->query('sort_by')) {
             'servers_count' => 'servers_count',
+            'backup_servers_count' => 'backup_servers_count',
             'name' => 'LOWER(name)',
             default => 'id',
         };
@@ -89,6 +90,7 @@ public function update(ServerPoolRequest $request, ServerPool $serverPool)
         $serverPool->name = $request->name;
         $serverPool->save();
         $serverPool->servers()->sync($request->servers);
+        $serverPool->backupServers()->sync($request->backup_servers);
 
         return (new ServerPoolResource($serverPool))->withServers();
     }
@@ -105,6 +107,7 @@ public function store(ServerPoolRequest $request)
         $serverPool->name = $request->name;
         $serverPool->save();
         $serverPool->servers()->sync($request->servers);
+        $serverPool->backupServers()->sync($request->backup_servers);
 
         return (new ServerPoolResource($serverPool))->withServers();
     }

diff --git a/app/Http/Requests/ServerPoolRequest.php b/app/Http/Requests/ServerPoolRequest.php
@@ -15,11 +15,16 @@ public function rules()
             'name' => ['required', 'string', 'max:255', Rule::unique('server_pools', 'name')],
             'description' => ['nullable', 'string', 'max:255'],
             'servers' => 'array',
+            // Backup servers are optional
+            // but if provided, they must be distinct and exist in the database
+            'backup_servers' => 'array',
             'servers.*' => ['distinct', 'integer', 'exists:App\Models\Server,id'],
+            'backup_servers.*' => ['distinct', 'integer', 'exists:App\Models\Server,id'],
         ];
 
         if ($this->serverPool) {
             $rules['name'] = ['required', 'string', 'max:255', Rule::unique('server_pools', 'name')->ignore($this->serverPool->id)];
+
         }
 
         return $rules;

diff --git a/app/Http/Resources/ServerPoolResource.php b/app/Http/Resources/ServerPoolResource.php
@@ -42,6 +42,10 @@ public function toArray($request)
             'servers' => $this->when($this->withServers, function () {
                 return ServerResource::collection($this->servers);
             }),
+            'backup_servers_count' => $this->backupServers()->count(),
+            'backup_servers' => $this->when($this->withServers, function () {
+                return ServerResource::collection($this->backupServers);
+            }),
             'model_name' => $this->model_name,
             'updated_at' => $this->updated_at,
         ];

diff --git a/app/Models/ServerPool.php b/app/Models/ServerPool.php
@@ -28,6 +28,14 @@ public function servers(): BelongsToMany
         return $this->belongsToMany(Server::class);
     }
 
+    /**
+     * Backup-Servers that are part of this server pool
+     */
+    public function backupServers(): BelongsToMany
+    {
+        return $this->belongsToMany(Server::class, 'backup_server_server_pool');
+    }
+
     /**
      * RoomTypes that are using this server pool
      *

diff --git a/app/Services/LoadBalancingService.php b/app/Services/LoadBalancingService.php
@@ -12,19 +12,40 @@ class LoadBalancingService
 {
     private $servers;
 
+    private $backupServers;
+
     public function setServerPool(ServerPool $serverPool)
     {
         $this->servers = $serverPool->servers;
+        $this->backupServers = $serverPool->backupServers;
 
         return $this;
     }
 
     /**
      * Find server in the pool with the lowest usage
+     *
+     * @return array{server:? Server, isPrefered:bool}
      */
-    public function getLowestUsageServer(): ?Server
+    public function getLowestUsageServer(): array
     {
-        return $this->servers
+        $preferredServer = $this->servers
+            ->where('status', ServerStatus::ENABLED)
+            ->where('recover_count', '>=', config('bigbluebutton.server_online_threshold'))
+            ->where('error_count', '=', 0)
+            ->whereNotNull('load')
+            ->sortBy(function (Server $server) {
+                return $server->load / $server->strength;
+            })
+            ->first();
+
+        // Check if the preferred server is available
+        if ($preferredServer) {
+            return ['server' => $preferredServer, 'isPreferred' => true];
+        }
+
+        // If no server is found, check backup servers
+        $backupServer = $this->backupServers
             ->where('status', ServerStatus::ENABLED)
             ->where('recover_count', '>=', config('bigbluebutton.server_online_threshold'))
             ->where('error_count', '=', 0)
@@ -33,5 +54,7 @@ public function getLowestUsageServer(): ?Server
                 return $server->load / $server->strength;
             })
             ->first();
+
+        return ['server' => $backupServer, 'isPreferred' => false];
     }
 }
diff --git a/app/Services/MeetingService.php b/app/Services/MeetingService.php
@@ -69,7 +69,7 @@ public function getCallbackUrl(): string
     /**
      * Start meeting with the properties saved for this meeting and room
      */
-    public function start(): ?CreateMeetingResponse
+    public function start(bool $isPreferredServer): ?CreateMeetingResponse
     {
         // Set meeting parameters
         $meetingParams = new CreateMeetingParameters($this->meeting->id, $this->meeting->room->name);
@@ -107,6 +107,12 @@ public function start(): ?CreateMeetingResponse
         $meetingParams->addMeta('bbb-origin', 'PILOS');
         $meetingParams->addMeta('pilos-sub-spool-dir', config('recording.spool-sub-directory'));
 
+        /* @TODO, optionally show banner on backup-server
+        if (! $isPreferredServer) {
+            $meetingParams->setBannerText('Test');
+            $meetingParams->setBannerColor('#DF2721');
+        }*/
+
         // get files that should be used in this meeting and add links to the files
         $files = $this->meeting->room->files()->where('use_in_meeting', true)->orderBy('default', 'desc')->get();
         foreach ($files as $file) {

diff --git a/app/Services/RoomService.php b/app/Services/RoomService.php
@@ -63,10 +63,15 @@ public function start(): MeetingService
 
             // Basic load balancing: get server with the lowest usage
             $loadBalancingService = new LoadBalancingService;
-            $server = $loadBalancingService
+            ['server' => $server, 'isPreferred' => $isPreferredServer] = $loadBalancingService
                 ->setServerPool($this->room->roomType->serverPool)
                 ->getLowestUsageServer();
 
+            // No preferred Server found, but backup server found
+            if (! $isPreferredServer && $server != null) {
+                Log::warning('No preferred server found! Fallback to backup server', ['room' => $this->room->getLogLabel()]);
+            }
+
             // If no server found, throw error
             if ($server == null) {
                 $lock->release();
@@ -84,20 +89,21 @@ public function start(): MeetingService
             $meeting->save();
 
             $meetingService = new MeetingService($meeting);
+            $serverType = $isPreferredServer ? 'server' : 'backup server';
 
-            Log::info('Starting new meeting for room {room} on server {server}', ['room' => $this->room->getLogLabel(), 'server' => $server->getLogLabel()]);
-            if (! $meetingService->start()) {
+            Log::info('Starting new meeting for room {room} on {serverType} {server}', ['room' => $this->room->getLogLabel(), 'serverType' => $serverType, 'server' => $server->getLogLabel()]);
+            if (! $meetingService->start($isPreferredServer)) {
                 // Creating Meeting failed, remove meeting
                 $meeting->forceDelete();
 
                 $lock->release();
-                Log::error('Failed to start meeting for room {room} on server {server}', ['room' => $this->room->getLogLabel(), 'server' => $server->getLogLabel()]);
+                Log::error('Failed to start meeting for room {room} on {serverType} {server}', ['room' => $this->room->getLogLabel(), 'serverType' => $serverType, 'server' => $server->getLogLabel()]);
                 Counter::get('room_start_errors_total')->inc('start_failed');
                 abort(CustomStatusCodes::ROOM_START_FAILED->value, __('app.errors.room_start'));
             }
 
             Counter::get('room_started_total')->inc();
-            Log::info('Successfully started new meeting for room {room} on server {server}', ['room' => $this->room->getLogLabel(), 'server' => $server->getLogLabel()]);
+            Log::info('Successfully started new meeting for room {room} on {serverType} {server}', ['room' => $this->room->getLogLabel(), 'server' => $server->getLogLabel()]);
 
             // Set start time after successful api call, prevents server poller from ending a meeting that has been started
             // but the api call has not been completed yet therefore the meeting will not be found on the server

diff --git a/database/migrations/2025_06_05_075646_create_backup_server_server_pool_table.php b/database/migrations/2025_06_05_075646_create_backup_server_server_pool_table.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Support\Facades\Schema;
+
+return new class extends Migration
+{
+    /**
+     * Run the migrations.
+     */
+    public function up(): void
+    {
+        Schema::create('backup_server_server_pool', function (Blueprint $table) {
+            $table->foreignId('server_id')->constrained()->onDelete('cascade');
+            $table->foreignId('server_pool_id')->constrained()->onDelete('cascade');
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     */
+    public function down(): void
+    {
+        Schema::dropIfExists('backup_server_server_pool');
+    }
+};
diff --git a/lang/en/admin.php b/lang/en/admin.php
@@ -94,8 +94,10 @@
                 'view_all' => 'Show all rooms',
             ],
             'server_pools' => [
+                'backup_servers' => 'Backup servers',
                 'create' => 'Create server pools',
                 'delete' => 'Delete server pools',
+                'select_server' => 'Select server',
                 'title' => 'Server pools',
                 'update' => 'Edit server pools',
                 'view' => 'Show server pools',
@@ -191,6 +193,8 @@
         'view' => 'Detailed information for the room type :name',
     ],
     'server_pools' => [
+        'backup_servers' => 'Backup servers',
+        'backup_server_count' => 'Number of backup servers',
         'delete' => [
             'confirm' => 'Do you really want to delete the server pool :name?',
             'failed' => 'Server pool can\'t be deleted because the following room types still use it:',

diff --git a/resources/js/views/AdminServerPoolsIndex.vue b/resources/js/views/AdminServerPoolsIndex.vue
@@ -99,6 +99,11 @@
         field="servers_count"
         sortable
       ></Column>
+      <Column
+        :header="$t('admin.server_pools.backup_server_count')"
+        field="backup_servers_count"
+        sortable
+      ></Column>
       <Column
         v-if="actionColumn.visible"
         :header="$t('app.actions')"

diff --git a/resources/js/views/AdminServerPoolsView.vue b/resources/js/views/AdminServerPoolsView.vue
@@ -93,6 +93,7 @@
           <div class="col-span-12 md:col-span-8">
             <InputGroup>
               <multiselect
+                id="servers"
                 ref="serversMultiselectRef"
                 v-model="model.servers"
                 data-test="server-dropdown"
@@ -179,6 +180,97 @@
             <FormError :errors="formErrors.fieldError('servers', true)" />
           </div>
         </div>
+        <!-- Begin server field for backup server -->
+        <div
+          class="field grid grid-cols-12 gap-4"
+          data-test="backup-server-field"
+        >
+          <label
+            id="backup-server-label"
+            class="col-span-12 md:col-span-4 md:mb-0"
+            >{{ $t("admin.server_pools.backup_servers") }}</label
+          >
+          <div class="col-span-12 md:col-span-8">
+            <InputGroup>
+              <multiselect
+                id="servers"
+                ref="backupServersMultiselectRef"
+                v-model="model.backup_servers"
+                data-test="backup-server-dropdown"
+                aria-labelledby="backup-servers-label"
+                :placeholder="$t('admin.server_pools.select_servers')"
+                track-by="id"
+                open-direction="bottom"
+                :multiple="true"
+                :searchable="false"
+                :internal-search="false"
+                :clear-on-select="false"
+                :close-on-select="false"
+                :show-no-results="false"
+                :show-labels="false"
+                :options="servers"
+                :disabled="
+                  isBusy ||
+                  modelLoadingError ||
+                  serversLoading ||
+                  serversLoadingError ||
+                  viewOnly
+                "
+                :loading="serversLoading"
+                :allow-empty="true"
+                :class="{
+                  'is-invalid': formErrors.fieldInvalid('backup_servers', true),
+                }"
+              >
+                <template #noOptions>
+                  {{ $t("admin.servers.no_data") }}
+                </template>
+                <template #option="{ option }">
+                  {{ option.name }}
+                </template>
+                <template #tag="{ option, remove }">
+                  <Chip :label="option.name" data-test="server-chip">
+                    <span>{{ option.name }}</span>
+                    <Button
+                      v-if="!viewOnly"
+                      severity="contrast"
+                      class="h-5 w-5 rounded-full text-sm"
+                      icon="fas fa-xmark"
+                      :aria-label="
+                        $t('admin.server_pools.remove_server', {
+                          name: option.name,
+                        })
+                      "
+                      data-test="remove-server-button"
+                      @click="remove(option)"
+                    />
+                  </Chip>
+                </template>
+                <template #afterList>
+                  <Button
+                    :disabled="serversLoading || serversCurrentPage === 1"
+                    outlined
+                    severity="secondary"
+                    icon="fa-solid fa-arrow-left"
+                    :label="$t('app.previous_page')"
+                    data-test="previous-page-button"
+                    @click="loadServers(Math.max(1, serversCurrentPage - 1))"
+                  />
+                  <Button
+                    :disabled="serversLoading || !serversHasNextPage"
+                    outlined
+                    severity="secondary"
+                    icon="fa-solid fa-arrow-right"
+                    :label="$t('app.next_page')"
+                    data-test="next-page-button"
+                    @click="loadServers(serversCurrentPage + 1)"
+                  />
+                </template>
+              </multiselect>
+            </InputGroup>
+          </div>
+        </div>
+        <!-- End server field for backup server -->
         <div v-if="!viewOnly">
           <div class="flex justify-end">
             <Button
@@ -256,6 +348,7 @@ const props = defineProps({
 
 const model = ref({
   servers: [],
+  backup_servers: [],
 });
 const name = ref("");
 
@@ -277,6 +370,7 @@ const serversCurrentPage = ref(1);
 const serversHasNextPage = ref(false);
 const serversLoadingError = ref(false);
 const serversMultiselectRef = ref(false);
+const backupServersMultiselectRef = ref(false);
 
 /**
  * Loads the server pool and servers from the backend
@@ -341,6 +435,7 @@ function loadServers(page = 1) {
     })
     .catch((error) => {
       serversMultiselectRef.value.deactivate();
+      backupServersMultiselectRef.value.deactivate();
       serversLoadingError.value = true;
       api.error(error);
     })
@@ -363,6 +458,9 @@ function saveServerPool() {
   };
 
   config.data.servers = config.data.servers.map((server) => server.id);
+  config.data.backup_servers = config.data.backup_servers.map(
+    (backupServer) => backupServer.id,
+  );
 
   api
     .call(