diff --git a/create-a-container/bin/create-container.js b/create-a-container/bin/create-container.js
index af221df9..289234ec 100755
--- a/create-a-container/bin/create-container.js
+++ b/create-a-container/bin/create-container.js
@@ -28,7 +28,7 @@ const path = require('path');
 
 // Load models from parent directory
 const db = require(path.join(__dirname, '..', 'models'));
-const { Container, Node, Site, Service, HTTPService, ExternalDomain, Setting, ResourceRequest } = db;
+const { Container, Node, Site, Service, HTTPService, ExternalDomain, Setting, ResourceRequest, Job } = db;
 
 // Load utilities
 const { parseArgs } = require(path.join(__dirname, '..', 'utils', 'cli'));
@@ -230,6 +230,15 @@ async function main() {
     console.log('Allocating VMID from Proxmox...');
     const vmid = await client.nextId();
     console.log(`Allocated VMID: ${vmid}`);
+
+    // Check if our job was cancelled (e.g., container was deleted while we were starting)
+    if (container.creationJobId) {
+      const job = await Job.findByPk(container.creationJobId);
+      if (job && job.status === 'cancelled') {
+        console.error('Job was cancelled — aborting container creation.');
+        process.exit(1);
+      }
+    }
     
     if (isDocker) {
       // Docker image: pull from OCI registry, then create container
@@ -341,6 +350,21 @@ async function main() {
       console.log('Container configured');
     }
     
+    // Verify the DB record still exists before proceeding.
+    // If another workflow deleted it while we were creating on Proxmox,
+    // destroy the orphan and abort to prevent duplicate containers.
+    const freshContainer = await Container.findByPk(container.id);
+    if (!freshContainer) {
+      console.error(`Container record ${container.id} was deleted during creation. Destroying orphaned Proxmox container ${vmid}...`);
+      try {
+        await client.deleteContainer(node.name, vmid, true, true);
+        console.log(`Orphaned Proxmox container ${vmid} destroyed successfully.`);
+      } catch (cleanupErr) {
+        console.error(`Failed to destroy orphaned container ${vmid}: ${cleanupErr.message}`);
+      }
+      process.exit(1);
+    }
+
     // Snapshot the template's env/entrypoint onto the container record now, as
     // if the user had supplied them (user-supplied values still win). Templates
     // are mutable Docker refs we can't re-query on a later reconfigure, so we
diff --git a/create-a-container/routers/api/v1/containers.js b/create-a-container/routers/api/v1/containers.js
index f962b776..f20edc95 100644
--- a/create-a-container/routers/api/v1/containers.js
+++ b/create-a-container/routers/api/v1/containers.js
@@ -413,6 +413,18 @@ router.post(
       } = req.body || {};
 
       if (!hostname || !hostname.trim()) throw new ApiError(400, 'invalid_request', 'hostname is required');
+      const existingContainer = await Container.findOne({
+        where: { siteId: site.id, hostname },
+        transaction: t,
+        lock: t.LOCK.UPDATE,
+      });
+      if (existingContainer) {
+        throw new ApiError(
+          409,
+          'duplicate_hostname',
+          `Container with hostname "${hostname}" already exists in this site`,
+        );
+      }
 
       // Contract: `collaborators`, when present, is an array of usernames.
       // Validated here so the insert below can trust its shape.
@@ -748,6 +760,12 @@ router.delete(
     );
     const node = container.node;
     let dnsWarnings = [];
+    if (container.creationJobId) {
+      const creationJob = await Job.findByPk(container.creationJobId);
+      if (creationJob && (creationJob.status === 'pending' || creationJob.status === 'running')) {
+        await creationJob.update({ status: 'cancelled' });
+      }
+    }
     const httpServices = (container.services || [])
       .filter((s) => s.httpService?.externalDomain)
       .map((s) => ({