feat: multi-cluster management with pool-based load balancing

- Add ClusterPool entity for grouping clusters into named pools
- Support 3 deployment modes: manual cluster, pool load-balanced, default fallback
- Pool strategies: least-apps (fewest deployed apps) and round-robin
- Add pool CRUD API endpoints (admin) and public pool listing
- Frontend deploy page: 3-mode cluster selector (Default/Manual/Pool)
- Frontend app detail: shows assigned cluster and pool info
- Admin pools management page with cluster selection and strategy picker
- Application entity extended with poolId field

backend/src/applications/applications.service.ts

@@ -20,22 +20,46 @@ export class ApplicationsService {
   ) {}
 
   async create(userId: string, dto: CreateApplicationDto): Promise<Application> {
-    // Auto-assign default cluster if not specified
+    // Cluster assignment: 3 modes
+    // 1. Manual: specific clusterId provided
+    // 2. Pool-based LB: poolId provided → pick from pool using pool's strategy
+    // 3. Default fallback: no clusterId/poolId → use default cluster
+
     let clusterId = dto.clusterId;
+    let poolId = dto.poolId;
+
     if (!clusterId) {
-      try {
-        const defaultCluster = await this.clustersService.getDefault();
-        clusterId = defaultCluster.id;
-        this.logger.log(`Auto-assigned default cluster "${defaultCluster.name}" to app "${dto.name}"`);
-      } catch {
-        this.logger.warn('No default cluster found — app will be created without cluster assignment');
+      if (poolId) {
+        // Mode 2: Pool-based load balancing
+        try {
+          const optimal = await this.clustersService.getOptimalClusterFromPool(poolId);
+          clusterId = optimal.id;
+          this.logger.log(`Pool-assigned cluster "${optimal.name}" to app "${dto.name}" (pool LB)`);
+        } catch (err: any) {
+          this.logger.warn(`Pool assignment failed for app "${dto.name}": ${err.message}`);
+          poolId = undefined; // Clear invalid pool
+        }
       }
+
+      // Mode 3: Default fallback (no manual cluster, no pool, or pool failed)
+      if (!clusterId) {
+        try {
+          const defaultCluster = await this.clustersService.getDefault();
+          clusterId = defaultCluster.id;
+          this.logger.log(`Default-assigned cluster "${defaultCluster.name}" to app "${dto.name}"`);
+        } catch {
+          this.logger.warn('No cluster available — app will be created without cluster assignment');
+        }
+      }
+    } else {
+      this.logger.log(`Manual cluster assignment for app "${dto.name}" → cluster ${clusterId}`);
     }
 
     const app = this.appsRepository.create({
       ...dto,
       userId,
       clusterId,
+      poolId,
       subdomain: `${dto.name}-${userId.split('-')[0]}`,
     });
     return this.appsRepository.save(app);

backend/src/applications/dto/application.dto.ts

@@ -88,6 +88,11 @@ export class CreateApplicationDto {
   @IsOptional()
   @IsString()
   clusterId?: string;
+
+  @ApiPropertyOptional({ description: 'Cluster pool ID for load-balanced deployment' })
+  @IsOptional()
+  @IsString()
+  poolId?: string;
 }
 
 export class UpdateApplicationDto {

backend/src/applications/entities/application.entity.ts

@@ -74,6 +74,9 @@ export class Application {
   @Column({ nullable: true })
   clusterId: string;
 
+  @Column({ nullable: true })
+  poolId: string; // Cluster pool used for load-balanced assignment
+
   @OneToMany(() => Deployment, (deployment: Deployment) => deployment.application)
   deployments: Deployment[];
 

backend/src/clusters/clusters.controller.ts

@@ -12,6 +12,7 @@ import { AuthGuard } from '@nestjs/passport';
 import { ApiTags, ApiOperation, ApiBearerAuth } from '@nestjs/swagger';
 import { ClustersService } from './clusters.service';
 import { CreateClusterDto, UpdateClusterDto } from './dto/cluster.dto';
+import { CreateClusterPoolDto, UpdateClusterPoolDto } from './dto/cluster-pool.dto';
 import { RolesGuard } from '../common/guards/roles.guard';
 import { Roles } from '../common/decorators/roles.decorator';
 import { UserRole } from '../common/enums';
@@ -20,44 +21,103 @@ import { UserRole } from '../common/enums';
 @ApiBearerAuth()
 @Controller('clusters')
 @UseGuards(AuthGuard('jwt'), RolesGuard)
-@Roles(UserRole.ADMIN)
 export class ClustersController {
   constructor(private readonly clustersService: ClustersService) {}
 
+  // ─── Public endpoints (any authenticated user) ────────────────────
+
+  @Get('public')
+  @ApiOperation({ summary: 'List available clusters (public info, no kubeconfig)' })
+  async findAllPublic() {
+    return this.clustersService.findAllPublic();
+  }
+
+  @Get('pools/public')
+  @ApiOperation({ summary: 'List active cluster pools with resolved cluster names' })
+  async findAllPoolsPublic() {
+    return this.clustersService.findAllPoolsPublic();
+  }
+
+  // ─── Cluster admin endpoints ──────────────────────────────────────
+
   @Post()
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Register a new Kubernetes cluster (Admin only)' })
   async create(@Body() dto: CreateClusterDto) {
     return this.clustersService.create(dto);
   }
 
   @Get()
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'List all clusters (Admin only)' })
   async findAll() {
     return this.clustersService.findAll();
   }
 
   @Get(':id')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Get cluster details (Admin only)' })
   async findOne(@Param('id') id: string) {
     return this.clustersService.findOne(id);
   }
 
   @Patch(':id')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Update cluster configuration (Admin only)' })
   async update(@Param('id') id: string, @Body() dto: UpdateClusterDto) {
     return this.clustersService.update(id, dto);
   }
 
   @Post(':id/test')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Test connectivity to a registered cluster (Admin only)' })
   async testConnection(@Param('id') id: string) {
     return this.clustersService.testClusterById(id);
   }
 
   @Delete(':id')
+  @Roles(UserRole.ADMIN)
   @ApiOperation({ summary: 'Remove a cluster (Admin only)' })
   async delete(@Param('id') id: string) {
     await this.clustersService.delete(id);
     return { message: 'Cluster deleted' };
   }
+
+  // ─── Cluster Pool admin endpoints ─────────────────────────────────
+
+  @Post('pools')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Create a cluster pool for load balancing (Admin only)' })
+  async createPool(@Body() dto: CreateClusterPoolDto) {
+    return this.clustersService.createPool(dto);
+  }
+
+  @Get('pools')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'List all cluster pools (Admin only)' })
+  async findAllPools() {
+    return this.clustersService.findAllPools();
+  }
+
+  @Get('pools/:id')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Get cluster pool details (Admin only)' })
+  async findOnePool(@Param('id') id: string) {
+    return this.clustersService.findOnePool(id);
+  }
+
+  @Patch('pools/:id')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Update cluster pool (Admin only)' })
+  async updatePool(@Param('id') id: string, @Body() dto: UpdateClusterPoolDto) {
+    return this.clustersService.updatePool(id, dto);
+  }
+
+  @Delete('pools/:id')
+  @Roles(UserRole.ADMIN)
+  @ApiOperation({ summary: 'Delete a cluster pool (Admin only)' })
+  async deletePool(@Param('id') id: string) {
+    await this.clustersService.deletePool(id);
+    return { message: 'Cluster pool deleted' };
+  }
 }

backend/src/clusters/clusters.module.ts

@@ -3,9 +3,10 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 import { ClustersService } from './clusters.service';
 import { ClustersController } from './clusters.controller';
 import { Cluster } from './entities/cluster.entity';
+import { ClusterPool } from './entities/cluster-pool.entity';
 
 @Module({
-  imports: [TypeOrmModule.forFeature([Cluster])],
+  imports: [TypeOrmModule.forFeature([Cluster, ClusterPool])],
   controllers: [ClustersController],
   providers: [ClustersService],
   exports: [ClustersService],

backend/src/clusters/clusters.service.ts

@@ -1,18 +1,25 @@
 import { Injectable, NotFoundException, Logger, BadRequestException } from '@nestjs/common';
 import { InjectRepository } from '@nestjs/typeorm';
-import { Repository } from 'typeorm';
+import { Repository, DataSource, In } from 'typeorm';
 import * as k8s from '@kubernetes/client-node';
 import { Cluster } from './entities/cluster.entity';
+import { ClusterPool } from './entities/cluster-pool.entity';
 import { CreateClusterDto, UpdateClusterDto } from './dto/cluster.dto';
+import { CreateClusterPoolDto, UpdateClusterPoolDto } from './dto/cluster-pool.dto';
 import { ClusterStatus } from '../common/enums';
 
 @Injectable()
 export class ClustersService {
   private readonly logger = new Logger(ClustersService.name);
+  private roundRobinIndex = 0;
+  private poolRoundRobinIndices = new Map<string, number>();
 
   constructor(
     @InjectRepository(Cluster)
     private clustersRepository: Repository<Cluster>,
+    @InjectRepository(ClusterPool)
+    private poolsRepository: Repository<ClusterPool>,
+    private dataSource: DataSource,
   ) {}
 
   /**
@@ -135,8 +142,210 @@ export class ClustersService {
     return result;
   }
 
+  /**
+   * Public cluster list (no sensitive data) — for users to select a cluster.
+   */
+  async findAllPublic(): Promise<Pick<Cluster, 'id' | 'name' | 'region' | 'provider' | 'isDefault' | 'status'>[]> {
+    return this.clustersRepository.find({
+      select: ['id', 'name', 'region', 'provider', 'isDefault', 'status'],
+      where: { status: ClusterStatus.ACTIVE },
+      order: { isDefault: 'DESC', name: 'ASC' },
+    });
+  }
+
+  /**
+   * Get the optimal cluster using load-balancing strategy.
+   * Strategy: 'least-apps' — picks the active cluster with fewest deployed applications.
+   * Falls back to default cluster if only one active cluster exists.
+   */
+  async getOptimalCluster(strategy: 'least-apps' | 'round-robin' = 'least-apps'): Promise<Cluster> {
+    const activeClusters = await this.clustersRepository.find({
+      where: { status: ClusterStatus.ACTIVE },
+    });
+
+    if (activeClusters.length === 0) {
+      throw new NotFoundException('No active clusters available');
+    }
+
+    if (activeClusters.length === 1) {
+      return activeClusters[0];
+    }
+
+    if (strategy === 'round-robin') {
+      const cluster = activeClusters[this.roundRobinIndex % activeClusters.length];
+      this.roundRobinIndex++;
+      this.logger.log(`Round-robin selected cluster "${cluster.name}" (index: ${this.roundRobinIndex - 1})`);
+      return cluster;
+    }
+
+    // least-apps: count applications per cluster
+    const appCounts: { clusterId: string; count: string }[] = await this.dataSource.query(`
+      SELECT "clusterId", COUNT(*) as count
+      FROM applications
+      WHERE "clusterId" IS NOT NULL
+      GROUP BY "clusterId"
+    `);
+
+    const countMap = new Map<string, number>();
+    for (const row of appCounts) {
+      countMap.set(row.clusterId, parseInt(row.count, 10));
+    }
+
+    // Sort by app count ascending (least apps first)
+    activeClusters.sort((a, b) => {
+      const countA = countMap.get(a.id) || 0;
+      const countB = countMap.get(b.id) || 0;
+      return countA - countB;
+    });
+
+    const selected = activeClusters[0];
+    const selectedCount = countMap.get(selected.id) || 0;
+    this.logger.log(`Least-apps selected cluster "${selected.name}" (${selectedCount} apps)`);
+    return selected;
+  }
+
   async delete(id: string): Promise<void> {
     const cluster = await this.findOne(id);
     await this.clustersRepository.remove(cluster);
   }
+
+  // ─── Cluster Pool Methods ─────────────────────────────────────────
+
+  async createPool(dto: CreateClusterPoolDto): Promise<ClusterPool> {
+    // Validate that all cluster IDs exist
+    if (dto.clusterIds.length === 0) {
+      throw new BadRequestException('Pool must contain at least one cluster');
+    }
+    const clusters = await this.clustersRepository.find({
+      where: { id: In(dto.clusterIds) },
+    });
+    if (clusters.length !== dto.clusterIds.length) {
+      const foundIds = clusters.map((c) => c.id);
+      const missingIds = dto.clusterIds.filter((id) => !foundIds.includes(id));
+      throw new BadRequestException(`Clusters not found: ${missingIds.join(', ')}`);
+    }
+
+    const pool = this.poolsRepository.create(dto);
+    const saved = await this.poolsRepository.save(pool);
+    this.logger.log(`Cluster pool "${saved.name}" created with ${dto.clusterIds.length} clusters (strategy: ${dto.strategy})`);
+    return saved;
+  }
+
+  async findAllPools(): Promise<ClusterPool[]> {
+    return this.poolsRepository.find({ order: { createdAt: 'DESC' } });
+  }
+
+  /**
+   * Public pool list — returns pools with resolved cluster names for UI.
+   */
+  async findAllPoolsPublic(): Promise<(ClusterPool & { clusters: Pick<Cluster, 'id' | 'name' | 'region' | 'provider' | 'status'>[] })[]> {
+    const pools = await this.poolsRepository.find({
+      where: { isActive: true },
+      order: { createdAt: 'DESC' },
+    });
+
+    const allClusterIds = [...new Set(pools.flatMap((p) => p.clusterIds))];
+    const clusters = allClusterIds.length > 0
+      ? await this.clustersRepository.find({
+          where: { id: In(allClusterIds) },
+          select: ['id', 'name', 'region', 'provider', 'status'],
+        })
+      : [];
+
+    const clusterMap = new Map(clusters.map((c) => [c.id, c]));
+
+    return pools.map((pool) => ({
+      ...pool,
+      clusters: pool.clusterIds
+        .map((id) => clusterMap.get(id))
+        .filter(Boolean) as Pick<Cluster, 'id' | 'name' | 'region' | 'provider' | 'status'>[],
+    }));
+  }
+
+  async findOnePool(id: string): Promise<ClusterPool> {
+    const pool = await this.poolsRepository.findOne({ where: { id } });
+    if (!pool) {
+      throw new NotFoundException('Cluster pool not found');
+    }
+    return pool;
+  }
+
+  async updatePool(id: string, dto: UpdateClusterPoolDto): Promise<ClusterPool> {
+    const pool = await this.findOnePool(id);
+
+    if (dto.clusterIds && dto.clusterIds.length > 0) {
+      const clusters = await this.clustersRepository.find({
+        where: { id: In(dto.clusterIds) },
+      });
+      if (clusters.length !== dto.clusterIds.length) {
+        const foundIds = clusters.map((c) => c.id);
+        const missingIds = dto.clusterIds.filter((cid) => !foundIds.includes(cid));
+        throw new BadRequestException(`Clusters not found: ${missingIds.join(', ')}`);
+      }
+    }
+
+    Object.assign(pool, dto);
+    return this.poolsRepository.save(pool);
+  }
+
+  async deletePool(id: string): Promise<void> {
+    const pool = await this.findOnePool(id);
+    await this.poolsRepository.remove(pool);
+    this.poolRoundRobinIndices.delete(id);
+  }
+
+  /**
+   * Get the optimal cluster from a specific pool using the pool's strategy.
+   * Only considers ACTIVE clusters within the pool.
+   */
+  async getOptimalClusterFromPool(poolId: string): Promise<Cluster> {
+    const pool = await this.findOnePool(poolId);
+    if (!pool.isActive) {
+      throw new BadRequestException(`Pool "${pool.name}" is not active`);
+    }
+
+    const activeClusters = await this.clustersRepository.find({
+      where: {
+        id: In(pool.clusterIds),
+        status: ClusterStatus.ACTIVE,
+      },
+    });
+
+    if (activeClusters.length === 0) {
+      throw new NotFoundException(`No active clusters in pool "${pool.name}"`);
+    }
+
+    if (activeClusters.length === 1) {
+      return activeClusters[0];
+    }
+
+    if (pool.strategy === 'round-robin') {
+      const idx = this.poolRoundRobinIndices.get(pool.id) || 0;
+      const cluster = activeClusters[idx % activeClusters.length];
+      this.poolRoundRobinIndices.set(pool.id, idx + 1);
+      this.logger.log(`Pool "${pool.name}" round-robin → cluster "${cluster.name}"`);
+      return cluster;
+    }
+
+    // least-apps strategy
+    const appCounts: { clusterId: string; count: string }[] = await this.dataSource.query(`
+      SELECT "clusterId", COUNT(*) as count
+      FROM applications
+      WHERE "clusterId" = ANY($1)
+      GROUP BY "clusterId"
+    `, [pool.clusterIds]);
+
+    const countMap = new Map<string, number>();
+    for (const row of appCounts) {
+      countMap.set(row.clusterId, parseInt(row.count, 10));
+    }
+
+    activeClusters.sort((a, b) => {
+      return (countMap.get(a.id) || 0) - (countMap.get(b.id) || 0);
+    });
+
+    const selected = activeClusters[0];
+    this.logger.log(`Pool "${pool.name}" least-apps → cluster "${selected.name}" (${countMap.get(selected.id) || 0} apps)`);
+    return selected;
+  }
 }

backend/src/clusters/dto/cluster-pool.dto.ts

@@ -0,0 +1,50 @@
+import { IsString, IsOptional, IsBoolean, IsArray, IsIn } from 'class-validator';
+import { ApiProperty, ApiPropertyOptional } from '@nestjs/swagger';
+
+export class CreateClusterPoolDto {
+  @ApiProperty({ example: 'production-pool' })
+  @IsString()
+  name: string;
+
+  @ApiPropertyOptional({ example: 'Load-balanced pool for production workloads' })
+  @IsOptional()
+  @IsString()
+  description?: string;
+
+  @ApiProperty({ example: 'least-apps', enum: ['least-apps', 'round-robin'] })
+  @IsIn(['least-apps', 'round-robin'])
+  strategy: 'least-apps' | 'round-robin';
+
+  @ApiProperty({ example: ['uuid-1', 'uuid-2'], description: 'Array of cluster IDs in this pool' })
+  @IsArray()
+  @IsString({ each: true })
+  clusterIds: string[];
+}
+
+export class UpdateClusterPoolDto {
+  @ApiPropertyOptional({ example: 'production-pool-v2' })
+  @IsOptional()
+  @IsString()
+  name?: string;
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsString()
+  description?: string;
+
+  @ApiPropertyOptional({ enum: ['least-apps', 'round-robin'] })
+  @IsOptional()
+  @IsIn(['least-apps', 'round-robin'])
+  strategy?: 'least-apps' | 'round-robin';
+
+  @ApiPropertyOptional({ description: 'Array of cluster IDs in this pool' })
+  @IsOptional()
+  @IsArray()
+  @IsString({ each: true })
+  clusterIds?: string[];
+
+  @ApiPropertyOptional()
+  @IsOptional()
+  @IsBoolean()
+  isActive?: boolean;
+}

backend/src/clusters/entities/cluster-pool.entity.ts

@@ -0,0 +1,40 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  UpdateDateColumn,
+} from 'typeorm';
+
+export type PoolStrategy = 'least-apps' | 'round-robin';
+
+@Entity('cluster_pools')
+export class ClusterPool {
+  @PrimaryGeneratedColumn('uuid')
+  id: string;
+
+  @Column()
+  name: string;
+
+  @Column({ nullable: true })
+  description: string;
+
+  @Column({ default: 'least-apps' })
+  strategy: PoolStrategy;
+
+  /**
+   * Array of cluster UUIDs that belong to this pool.
+   * Only active clusters from this list will be considered for load balancing.
+   */
+  @Column({ type: 'jsonb', default: [] })
+  clusterIds: string[];
+
+  @Column({ default: true })
+  isActive: boolean;
+
+  @CreateDateColumn()
+  createdAt: Date;
+
+  @UpdateDateColumn()
+  updatedAt: Date;
+}

frontend/src/app/dashboard/admin/pools/page.tsx

@@ -0,0 +1,326 @@
+'use client';
+
+import { useState } from 'react';
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import api from '@/lib/api';
+import toast from 'react-hot-toast';
+import type { Cluster, ClusterPool } from '@/types';
+
+export default function AdminPoolsPage() {
+  const queryClient = useQueryClient();
+  const [showForm, setShowForm] = useState(false);
+  const [editingPool, setEditingPool] = useState<ClusterPool | null>(null);
+  const [form, setForm] = useState({
+    name: '',
+    description: '',
+    strategy: 'least-apps' as 'least-apps' | 'round-robin',
+    clusterIds: [] as string[],
+  });
+
+  const { data: pools = [], isLoading } = useQuery<ClusterPool[]>({
+    queryKey: ['admin-pools'],
+    queryFn: () => api.get('/clusters/pools').then((r) => r.data),
+  });
+
+  const { data: clusters = [] } = useQuery<Cluster[]>({
+    queryKey: ['admin-clusters'],
+    queryFn: () => api.get('/clusters').then((r) => r.data),
+  });
+
+  const createMutation = useMutation({
+    mutationFn: (data: typeof form) => api.post('/clusters/pools', data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-pools'] });
+      toast.success('Cluster pool created!');
+      resetForm();
+    },
+    onError: (err: any) => {
+      toast.error(err?.response?.data?.message || 'Failed to create pool');
+    },
+  });
+
+  const updateMutation = useMutation({
+    mutationFn: ({ id, data }: { id: string; data: typeof form }) =>
+      api.patch(`/clusters/pools/${id}`, data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-pools'] });
+      toast.success('Cluster pool updated!');
+      resetForm();
+    },
+    onError: (err: any) => {
+      toast.error(err?.response?.data?.message || 'Failed to update pool');
+    },
+  });
+
+  const deleteMutation = useMutation({
+    mutationFn: (id: string) => api.delete(`/clusters/pools/${id}`),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['admin-pools'] });
+      toast.success('Cluster pool deleted');
+    },
+  });
+
+  const resetForm = () => {
+    setShowForm(false);
+    setEditingPool(null);
+    setForm({ name: '', description: '', strategy: 'least-apps', clusterIds: [] });
+  };
+
+  const startEdit = (pool: ClusterPool) => {
+    setEditingPool(pool);
+    setForm({
+      name: pool.name,
+      description: pool.description || '',
+      strategy: pool.strategy,
+      clusterIds: pool.clusterIds,
+    });
+    setShowForm(true);
+  };
+
+  const handleSubmit = () => {
+    if (editingPool) {
+      updateMutation.mutate({ id: editingPool.id, data: form });
+    } else {
+      createMutation.mutate(form);
+    }
+  };
+
+  const toggleCluster = (clusterId: string) => {
+    setForm((prev) => ({
+      ...prev,
+      clusterIds: prev.clusterIds.includes(clusterId)
+        ? prev.clusterIds.filter((id) => id !== clusterId)
+        : [...prev.clusterIds, clusterId],
+    }));
+  };
+
+  return (
+    <div className="space-y-6">
+      <div className="flex justify-between items-center">
+        <div>
+          <h1 className="text-2xl font-bold text-gray-900">Cluster Pools</h1>
+          <p className="text-sm text-gray-500 mt-1">
+            Create load-balanced groups of clusters for automatic app distribution
+          </p>
+        </div>
+        <button
+          onClick={() => { showForm ? resetForm() : setShowForm(true); }}
+          className="btn-primary"
+        >
+          {showForm ? 'Cancel' : '+ Create Pool'}
+        </button>
+      </div>
+
+      {/* Create/Edit Form */}
+      {showForm && (
+        <div className="card space-y-4">
+          <h2 className="text-lg font-semibold">
+            {editingPool ? `Edit "${editingPool.name}"` : 'Create New Cluster Pool'}
+          </h2>
+
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="block text-sm font-medium text-gray-700 mb-1">Pool Name</label>
+              <input
+                className="input-field"
+                placeholder="production-pool"
+                value={form.name}
+                onChange={(e) => setForm({ ...form, name: e.target.value })}
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium text-gray-700 mb-1">Strategy</label>
+              <select
+                className="input-field"
+                value={form.strategy}
+                onChange={(e) => setForm({ ...form, strategy: e.target.value as any })}
+              >
+                <option value="least-apps">📊 Least Apps — deploy to cluster with fewest apps</option>
+                <option value="round-robin">🔄 Round Robin — rotate across clusters evenly</option>
+              </select>
+            </div>
+          </div>
+
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-1">Description</label>
+            <input
+              className="input-field"
+              placeholder="Load-balanced pool for production workloads"
+              value={form.description}
+              onChange={(e) => setForm({ ...form, description: e.target.value })}
+            />
+          </div>
+
+          {/* Cluster selection */}
+          <div>
+            <label className="block text-sm font-medium text-gray-700 mb-2">
+              Select Clusters ({form.clusterIds.length} selected)
+            </label>
+            {clusters.length === 0 ? (
+              <p className="text-sm text-gray-400 py-4 text-center">
+                No clusters registered. Add clusters first.
+              </p>
+            ) : (
+              <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
+                {clusters.map((cluster) => {
+                  const isSelected = form.clusterIds.includes(cluster.id);
+                  return (
+                    <button
+                      key={cluster.id}
+                      type="button"
+                      onClick={() => toggleCluster(cluster.id)}
+                      className={`p-3 rounded-xl border-2 text-left transition-all ${
+                        isSelected
+                          ? 'border-primary-500 bg-primary-50 shadow-sm'
+                          : 'border-gray-200 hover:border-gray-300'
+                      }`}
+                    >
+                      <div className="flex items-center justify-between">
+                        <div className="flex items-center space-x-3">
+                          <div className={`w-5 h-5 rounded border-2 flex items-center justify-center ${
+                            isSelected ? 'border-primary-500 bg-primary-500' : 'border-gray-300'
+                          }`}>
+                            {isSelected && <span className="text-white text-xs">✓</span>}
+                          </div>
+                          <div>
+                            <p className="font-semibold text-sm text-gray-900">
+                              {cluster.name}
+                              {cluster.isDefault && (
+                                <span className="ml-2 text-xs bg-blue-100 text-blue-700 px-1.5 py-0.5 rounded">
+                                  Default
+                                </span>
+                              )}
+                            </p>
+                            <p className="text-xs text-gray-500">
+                              {cluster.provider || 'Unknown'} · {cluster.region || 'N/A'}
+                            </p>
+                          </div>
+                        </div>
+                        <span className={`px-2 py-0.5 rounded-full text-xs font-medium ${
+                          cluster.status === 'active'
+                            ? 'bg-green-100 text-green-700'
+                            : 'bg-red-100 text-red-700'
+                        }`}>
+                          {cluster.status}
+                        </span>
+                      </div>
+                    </button>
+                  );
+                })}
+              </div>
+            )}
+          </div>
+
+          <div className="flex space-x-3">
+            <button
+              onClick={handleSubmit}
+              disabled={
+                !form.name ||
+                form.clusterIds.length === 0 ||
+                createMutation.isPending ||
+                updateMutation.isPending
+              }
+              className="btn-primary disabled:opacity-50"
+            >
+              {createMutation.isPending || updateMutation.isPending
+                ? '⏳ Saving...'
+                : editingPool
+                ? 'Update Pool'
+                : 'Create Pool'}
+            </button>
+            <button onClick={resetForm} className="btn-secondary">
+              Cancel
+            </button>
+          </div>
+        </div>
+      )}
+
+      {/* Pool List */}
+      {isLoading ? (
+        <div className="card text-center py-12 text-gray-500">Loading pools...</div>
+      ) : pools.length === 0 ? (
+        <div className="card text-center py-12">
+          <div className="text-4xl mb-3">⚖️</div>
+          <p className="text-gray-500">No cluster pools created yet</p>
+          <p className="text-sm text-gray-400 mt-1">
+            Create a pool to enable load-balanced deployment across multiple clusters
+          </p>
+        </div>
+      ) : (
+        <div className="grid gap-4">
+          {pools.map((pool) => {
+            const poolClusters = clusters.filter((c) => pool.clusterIds.includes(c.id));
+            const activeClusters = poolClusters.filter((c) => c.status === 'active');
+            return (
+              <div key={pool.id} className="card">
+                <div className="flex items-start justify-between">
+                  <div className="flex-1">
+                    <div className="flex items-center space-x-3 mb-2">
+                      <h3 className="text-lg font-semibold text-gray-900">{pool.name}</h3>
+                      <span className={`px-2 py-0.5 rounded-full text-xs font-medium ${
+                        pool.isActive ? 'bg-green-100 text-green-700' : 'bg-gray-100 text-gray-500'
+                      }`}>
+                        {pool.isActive ? 'Active' : 'Inactive'}
+                      </span>
+                      <span className="px-2 py-0.5 bg-purple-100 text-purple-700 text-xs rounded-full font-medium">
+                        {pool.strategy === 'least-apps' ? '📊 Least Apps' : '🔄 Round Robin'}
+                      </span>
+                    </div>
+                    {pool.description && (
+                      <p className="text-sm text-gray-500 mb-3">{pool.description}</p>
+                    )}
+
+                    {/* Cluster chips */}
+                    <div className="flex flex-wrap gap-2">
+                      {poolClusters.length > 0 ? poolClusters.map((cluster) => (
+                        <div
+                          key={cluster.id}
+                          className={`inline-flex items-center space-x-1.5 px-3 py-1.5 rounded-lg text-xs font-medium ${
+                            cluster.status === 'active'
+                              ? 'bg-green-50 text-green-700 border border-green-200'
+                              : 'bg-red-50 text-red-700 border border-red-200'
+                          }`}
+                        >
+                          <span>{cluster.status === 'active' ? '✅' : '❌'}</span>
+                          <span>{cluster.name}</span>
+                          <span className="text-gray-400">
+                            ({cluster.provider || 'N/A'} · {cluster.region || 'N/A'})
+                          </span>
+                        </div>
+                      )) : (
+                        <p className="text-xs text-gray-400">No clusters in this pool (they may have been deleted)</p>
+                      )}
+                    </div>
+
+                    <p className="text-xs text-gray-400 mt-2">
+                      {activeClusters.length}/{poolClusters.length} clusters active · Created {new Date(pool.createdAt).toLocaleDateString()}
+                    </p>
+                  </div>
+
+                  <div className="flex items-center space-x-3 ml-4">
+                    <button
+                      onClick={() => startEdit(pool)}
+                      className="text-sm px-3 py-1.5 bg-blue-50 text-blue-700 rounded-md hover:bg-blue-100 transition-colors"
+                    >
+                      ✏️ Edit
+                    </button>
+                    <button
+                      onClick={() => {
+                        if (confirm(`Delete pool "${pool.name}"? Apps already assigned to this pool will keep their current cluster.`)) {
+                          deleteMutation.mutate(pool.id);
+                        }
+                      }}
+                      className="text-sm text-red-600 hover:text-red-800"
+                    >
+                      Remove
+                    </button>
+                  </div>
+                </div>
+              </div>
+            );
+          })}
+        </div>
+      )}
+    </div>
+  );
+}

frontend/src/app/dashboard/apps/[id]/page.tsx

@@ -4,7 +4,7 @@ import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
 import { useParams, useRouter } from 'next/navigation';
 import api from '@/lib/api';
 import toast from 'react-hot-toast';
-import type { Application, Deployment, ResourceUsage } from '@/types';
+import type { Application, Deployment, ResourceUsage, ClusterPublic, ClusterPoolPublic } from '@/types';
 import { useState, useRef, useCallback, useEffect } from 'react';
 
 const statusColors: Record<string, string> = {
@@ -85,6 +85,16 @@ export default function AppDetailPage() {
     refetchInterval: showResources ? 5000 : false,
   });
 
+  const { data: clusters = [] } = useQuery<ClusterPublic[]>({
+    queryKey: ['clusters-public'],
+    queryFn: () => api.get('/clusters/public').then((r) => r.data),
+  });
+
+  const { data: pools = [] } = useQuery<ClusterPoolPublic[]>({
+    queryKey: ['pools-public'],
+    queryFn: () => api.get('/clusters/pools/public').then((r) => r.data),
+  });
+
   // Sync form when resource data loads
   useEffect(() => {
     if (resourceUsage?.configured) {
@@ -378,6 +388,22 @@ export default function AppDetailPage() {
               <dt className="text-sm text-gray-500">Port</dt>
               <dd className="text-sm font-medium text-gray-900">{app.port}</dd>
             </div>
+            {app.clusterId && (
+              <div className="flex justify-between">
+                <dt className="text-sm text-gray-500">Cluster</dt>
+                <dd className="text-sm font-medium text-gray-900">
+                  🖥️ {clusters.find((c) => c.id === app.clusterId)?.name || 'Unknown'}
+                </dd>
+              </div>
+            )}
+            {app.poolId && (
+              <div className="flex justify-between">
+                <dt className="text-sm text-gray-500">Pool</dt>
+                <dd className="text-sm font-medium text-gray-900">
+                  ⚖️ {pools.find((p) => p.id === app.poolId)?.name || 'Unknown'}
+                </dd>
+              </div>
+            )}
             {app.latestImageTag && (
               <div className="flex justify-between">
                 <dt className="text-sm text-gray-500">Image</dt>

frontend/src/app/dashboard/deploy/page.tsx

@@ -2,10 +2,10 @@
 
 import { useState, useRef, useCallback } from 'react';
 import { useRouter } from 'next/navigation';
-import { useMutation } from '@tanstack/react-query';
+import { useMutation, useQuery } from '@tanstack/react-query';
 import api from '@/lib/api';
 import toast from 'react-hot-toast';
-import type { CreateApplicationDto } from '@/types';
+import type { CreateApplicationDto, ClusterPublic, ClusterPoolPublic } from '@/types';
 
 const steps = ['Basic Info', 'Runtime & Database', 'Resources', 'Review'];
 
@@ -34,8 +34,19 @@ export default function DeployPage() {
   const [zipFile, setZipFile] = useState<File | null>(null);
   const [uploadProgress, setUploadProgress] = useState(0);
   const [isDragging, setIsDragging] = useState(false);
+  const [clusterMode, setClusterMode] = useState<'default' | 'manual' | 'pool'>('default');
   const fileInputRef = useRef<HTMLInputElement>(null);
 
+  const { data: clusters = [] } = useQuery<ClusterPublic[]>({
+    queryKey: ['clusters-public'],
+    queryFn: () => api.get('/clusters/public').then((r) => r.data),
+  });
+
+  const { data: pools = [] } = useQuery<ClusterPoolPublic[]>({
+    queryKey: ['pools-public'],
+    queryFn: () => api.get('/clusters/pools/public').then((r) => r.data),
+  });
+
   const createMutation = useMutation({
     mutationFn: async (data: CreateApplicationDto) => {
       const res = await api.post('/applications', data);
@@ -367,6 +378,170 @@ export default function DeployPage() {
         {step === 2 && (
           <div className="space-y-6">
             <h2 className="text-lg font-semibold">Resources & Configuration</h2>
+
+            {/* Cluster Assignment Mode */}
+            <div>
+              <label className="block text-sm font-medium text-gray-700 mb-2">Cluster Assignment</label>
+              <div className="grid grid-cols-3 gap-3 mb-4">
+                <button
+                  type="button"
+                  onClick={() => {
+                    setClusterMode('default');
+                    setForm({ ...form, clusterId: undefined, poolId: undefined });
+                  }}
+                  className={`p-3 rounded-xl border-2 text-center transition-colors ${
+                    clusterMode === 'default'
+                      ? 'border-primary-500 bg-primary-50'
+                      : 'border-gray-200 hover:border-gray-300'
+                  }`}
+                >
+                  <span className="text-xl">🏠</span>
+                  <p className="mt-1 font-semibold text-sm text-gray-900">Default</p>
+                  <p className="text-xs text-gray-500">Use default cluster</p>
+                </button>
+                <button
+                  type="button"
+                  onClick={() => {
+                    setClusterMode('manual');
+                    setForm({ ...form, poolId: undefined });
+                  }}
+                  className={`p-3 rounded-xl border-2 text-center transition-colors ${
+                    clusterMode === 'manual'
+                      ? 'border-primary-500 bg-primary-50'
+                      : 'border-gray-200 hover:border-gray-300'
+                  }`}
+                >
+                  <span className="text-xl">🎯</span>
+                  <p className="mt-1 font-semibold text-sm text-gray-900">Manual</p>
+                  <p className="text-xs text-gray-500">Pick a specific cluster</p>
+                </button>
+                <button
+                  type="button"
+                  onClick={() => {
+                    setClusterMode('pool');
+                    setForm({ ...form, clusterId: undefined });
+                  }}
+                  className={`p-3 rounded-xl border-2 text-center transition-colors ${
+                    clusterMode === 'pool'
+                      ? 'border-primary-500 bg-primary-50'
+                      : 'border-gray-200 hover:border-gray-300'
+                  }`}
+                >
+                  <span className="text-xl">⚖️</span>
+                  <p className="mt-1 font-semibold text-sm text-gray-900">Load Balanced</p>
+                  <p className="text-xs text-gray-500">Pick a cluster pool</p>
+                </button>
+              </div>
+
+              {/* Manual: show cluster list */}
+              {clusterMode === 'manual' && (
+                <div className="space-y-2">
+                  {clusters.length === 0 ? (
+                    <p className="text-sm text-gray-400 text-center py-4">No clusters available</p>
+                  ) : (
+                    clusters.map((cluster) => (
+                      <button
+                        key={cluster.id}
+                        type="button"
+                        onClick={() => setForm({ ...form, clusterId: cluster.id })}
+                        className={`w-full p-3 rounded-xl border-2 text-left transition-colors ${
+                          form.clusterId === cluster.id
+                            ? 'border-primary-500 bg-primary-50'
+                            : 'border-gray-200 hover:border-gray-300'
+                        }`}
+                      >
+                        <div className="flex items-center justify-between">
+                          <div className="flex items-center space-x-3">
+                            <span className="text-lg">🖥️</span>
+                            <div>
+                              <p className="font-semibold text-sm text-gray-900">
+                                {cluster.name}
+                                {cluster.isDefault && (
+                                  <span className="ml-2 text-xs bg-blue-100 text-blue-700 px-1.5 py-0.5 rounded">Default</span>
+                                )}
+                              </p>
+                              <p className="text-xs text-gray-500">
+                                {[cluster.provider, cluster.region].filter(Boolean).join(' · ') || 'No region info'}
+                              </p>
+                            </div>
+                          </div>
+                          <span className={`px-2 py-0.5 rounded-full text-xs font-medium ${
+                            cluster.status === 'active' ? 'bg-green-100 text-green-700' : 'bg-gray-100 text-gray-500'
+                          }`}>
+                            {cluster.status}
+                          </span>
+                        </div>
+                      </button>
+                    ))
+                  )}
+                </div>
+              )}
+
+              {/* Pool: show pool list */}
+              {clusterMode === 'pool' && (
+                <div className="space-y-2">
+                  {pools.length === 0 ? (
+                    <div className="text-center py-4">
+                      <p className="text-sm text-gray-400">No cluster pools configured</p>
+                      <p className="text-xs text-gray-400 mt-1">Ask your admin to create a cluster pool</p>
+                    </div>
+                  ) : (
+                    pools.map((pool) => (
+                      <button
+                        key={pool.id}
+                        type="button"
+                        onClick={() => setForm({ ...form, poolId: pool.id })}
+                        className={`w-full p-3 rounded-xl border-2 text-left transition-colors ${
+                          form.poolId === pool.id
+                            ? 'border-primary-500 bg-primary-50'
+                            : 'border-gray-200 hover:border-gray-300'
+                        }`}
+                      >
+                        <div className="flex items-center justify-between">
+                          <div className="flex items-center space-x-3">
+                            <span className="text-lg">⚖️</span>
+                            <div>
+                              <p className="font-semibold text-sm text-gray-900">{pool.name}</p>
+                              {pool.description && (
+                                <p className="text-xs text-gray-500">{pool.description}</p>
+                              )}
+                              <div className="flex items-center space-x-2 mt-1">
+                                <span className="text-xs bg-purple-100 text-purple-700 px-1.5 py-0.5 rounded">
+                                  {pool.strategy === 'least-apps' ? '📊 Least Apps' : '🔄 Round Robin'}
+                                </span>
+                                <span className="text-xs text-gray-400">
+                                  {pool.clusters.length} cluster{pool.clusters.length !== 1 ? 's' : ''}:
+                                  {' '}{pool.clusters.map((c) => c.name).join(', ')}
+                                </span>
+                              </div>
+                            </div>
+                          </div>
+                        </div>
+                      </button>
+                    ))
+                  )}
+                </div>
+              )}
+
+              {/* Default: info text */}
+              {clusterMode === 'default' && (
+                <div className="p-3 bg-gray-50 rounded-xl border border-gray-200">
+                  <div className="flex items-center space-x-3">
+                    <span className="text-lg">🏠</span>
+                    <div>
+                      <p className="text-sm font-medium text-gray-700">Default cluster will be used</p>
+                      <p className="text-xs text-gray-500">
+                        Your app will be deployed to the platform&apos;s default cluster
+                        {clusters.find((c) => c.isDefault) && (
+                          <> — <strong>{clusters.find((c) => c.isDefault)?.name}</strong></>
+                        )}
+                      </p>
+                    </div>
+                  </div>
+                </div>
+              )}
+            </div>
+
             <div className="grid grid-cols-2 gap-4">
               <div>
                 <label className="block text-sm font-medium text-gray-700 mb-1">CPU Request</label>
@@ -497,6 +672,16 @@ export default function DeployPage() {
                   <span className="text-sm font-medium text-green-600">🔑 Token provided</span>
                 </div>
               )}
+              <div className="flex justify-between">
+                <span className="text-sm text-gray-500">Cluster</span>
+                <span className="text-sm font-medium">
+                  {clusterMode === 'manual' && form.clusterId
+                    ? `🎯 ${clusters.find((c) => c.id === form.clusterId)?.name || form.clusterId}`
+                    : clusterMode === 'pool' && form.poolId
+                    ? `⚖️ ${pools.find((p) => p.id === form.poolId)?.name || 'Pool'} (Load Balanced)`
+                    : '🏠 Default Cluster'}
+                </span>
+              </div>
               <div className="flex justify-between">
                 <span className="text-sm text-gray-500">CPU</span>
                 <span className="text-sm font-medium">{form.cpuRequest} / {form.cpuLimit}</span>

frontend/src/app/dashboard/layout.tsx

@@ -14,6 +14,7 @@ const userNavItems = [
 const adminNavItems = [
   { href: '/dashboard/admin/users', label: 'Users', icon: '👥' },
   { href: '/dashboard/admin/clusters', label: 'Clusters', icon: '🖥️' },
+  { href: '/dashboard/admin/pools', label: 'Cluster Pools', icon: '⚖️' },
 ];
 
 export default function DashboardLayout({ children }: { children: React.ReactNode }) {

frontend/src/types/index.ts

@@ -28,6 +28,7 @@ export interface Application {
   port: number;
   userId: string;
   clusterId?: string;
+  poolId?: string;
   latestImageTag?: string;
   subdomain?: string;
   deployments?: Deployment[];
@@ -95,6 +96,37 @@ export interface CreateApplicationDto {
   memoryLimit?: string;
   replicas?: number;
   port?: number;
+  clusterId?: string;
+  poolId?: string;
+}
+
+export interface ClusterPublic {
+  id: string;
+  name: string;
+  region?: string;
+  provider?: string;
+  isDefault: boolean;
+  status: 'active' | 'inactive' | 'maintenance';
+}
+
+export interface ClusterPoolPublic {
+  id: string;
+  name: string;
+  description?: string;
+  strategy: 'least-apps' | 'round-robin';
+  clusterIds: string[];
+  isActive: boolean;
+  clusters: Pick<ClusterPublic, 'id' | 'name' | 'region' | 'provider' | 'status'>[];
+}
+
+export interface ClusterPool {
+  id: string;
+  name: string;
+  description?: string;
+  strategy: 'least-apps' | 'round-robin';
+  clusterIds: string[];
+  isActive: boolean;
+  createdAt: string;
 }
 
 export interface PodInfo {