diff --git a/scripts/timezone.js b/scripts/timezone.js
index 369ea9e..1568c3d 100644
--- a/scripts/timezone.js
+++ b/scripts/timezone.js
@@ -7,6 +7,11 @@ document.addEventListener('DOMContentLoaded', function () {
     const elements = document.getElementsByClassName('to-local-time');
     for (let element of elements) {
         const innerText = element.innerText;
-        element.replaceChild(document.createTextNode(window.formatTime(innerText)), element.firstChild);
+        if (element.firstChild) {
+            element.replaceChild(document.createTextNode(window.formatTime(innerText)), element.firstChild);
+        }
+        else {
+            element.appendChild(document.createTextNode('-'));
+        }
     }
 });
\ No newline at end of file
diff --git a/src/BuildController.ts b/src/BuildController.ts
index a43f2f2..476b16c 100644
--- a/src/BuildController.ts
+++ b/src/BuildController.ts
@@ -15,11 +15,15 @@ interface BuildEvent {
     message: any;
 }
 
+function getContainerName(id: number) {
+    return `archery-build-${id}`;
+}
+
 class BuildController extends EventEmitter {
     private db: DB;
-    private process: spawn.ChildProcess | null = null;
     private running: boolean = false;
     private interval: NodeJS.Timeout;
+    private cancelled: boolean = false;
 
     constructor(config = {}) {
         super();
@@ -37,6 +41,7 @@ class BuildController extends EventEmitter {
 
     private kickOffBuild = async () => {
         this.running = true;
+        this.cancelled = false;
         const build = await this.db.dequeue();
         if (build === null) {
             this.running = false;
@@ -80,7 +85,7 @@ class BuildController extends EventEmitter {
 
     private build = async (build: Build) => {
         return new Promise<void>((resolve, reject) => {
-            const docker = this.process = spawn.spawn('docker', this.createBuildParams(build));
+            const docker = spawn.spawn('docker', this.createBuildParams(build));
             docker.on('spawn', () => {
                 const remainder = {
                     std: '',
@@ -106,8 +111,7 @@ class BuildController extends EventEmitter {
                 docker.stderr.on('data', createLogFunction('err'));
             });
             docker.on('close', (code) => {
-                this.process = null;
-                const status = code === 0 ? 'success' : 'error';
+                const status = code === 0 ? 'success' : (this.cancelled ? 'cancelled' : 'error');
                 this.emitLog({
                     id: build.id,
                     type: 'finish',
@@ -115,12 +119,7 @@ class BuildController extends EventEmitter {
                 });
                 this.db.finishBuild(build.id, status);
 
-                if (code === 0) {
-                    resolve();
-                }
-                else {
-                    reject(code);
-                }
+                resolve();
             });
         });
     }
@@ -136,15 +135,40 @@ class BuildController extends EventEmitter {
             // TODO: implement COMMIT
             params.push('-e', `COMMIT=${build.commit}`);
         }
+        params.push('--name', getContainerName(build.id));
         params.push(docker_images[build.distro]);
         return params;
     }
 
-    cancelBuild = async (pid: number) => {
-        const p = this.process
-        if (p && p.pid === pid) {
-            return p.kill();
+    cancelBuild = async (id: number) => {
+        const running = this.running;
+        const build = await this.db.getBuild(id);
+        if (running && build.status === 'queued') {
+            await this.db.finishBuild(id, 'cancelled');
+            return;
         }
+        await new Promise<void>((resolve, reject) => {
+            const dockerPs = spawn.spawn('docker', ['ps', '--filter', `name=${getContainerName(id)}`, '--format', '{{.ID}}']);
+            let output = '';
+            dockerPs.on('spawn', () => {
+                dockerPs.stdout.on('data', (data: Buffer | string) => {
+                    output += data.toString();
+                });
+            });
+            dockerPs.on('close', (code) => {
+                if (code > 0) {
+                    return reject('failed to get container id');
+                }
+                this.cancelled = true;
+                const dockerKill = spawn.spawn('docker', ['stop', output.trim()]);
+                dockerKill.on('close', (code) => {
+                    if (code > 0) {
+                        return reject('failed to kill container');
+                    }
+                    resolve();
+                });
+            });
+        });
     }
 
     setDB = (db: DB) => {
diff --git a/src/Web.ts b/src/Web.ts
index 02fec01..81c7093 100644
--- a/src/Web.ts
+++ b/src/Web.ts
@@ -19,7 +19,7 @@ function notStupidParseInt(v: string | undefined): number {
 }
 
 function timeElapsed(date1: Date, date2: Date) {
-    if (!date2 || ! date1) {
+    if (!date2 || !date1) {
         return '-';
     }
     const ms = Math.abs(date2.getTime() - date1.getTime());
@@ -33,12 +33,12 @@ class Web {
     private _webserver: http.Server | null = null;
     private db: DB;
     private buildController: BuildController;
-    private app: Express;
+    private app: expressWs.Application;
     private port: number;
 
     constructor(options: WebConfig = {}) {
-        const app: Express = this.app = express();
-        const wsApp = expressWs(app).app;
+        const app: Express = express();
+        const wsApp = this.app = expressWs(app).app;
         this.port = notStupidParseInt(process.env.PORT) || options['port'] as number || 8080;
 
         app.set('trust proxy', 1);
@@ -120,6 +120,21 @@ class Web {
             });
         });
 
+        app.get('/build/:num/cancel', async (req, res) => {
+            const build = await this.db.getBuild(parseInt(req.params.num));
+            if (!build) {
+                res.sendStatus(404);
+                return;
+            }
+            try {
+                await this.buildController.cancelBuild(build.id);
+            }
+            catch (ex) {
+                console.error(ex);
+            }
+            res.redirect(`/build/${build.id}`);
+        });
+
         app.get('/build/:num/logs/?', async (req, res) => {
             const build = await this.db.getBuild(parseInt(req.params.num));
             if (!build) {
diff --git a/styles/01-styles.scss b/styles/01-styles.scss
index 9c7ad0b..f73cbfb 100644
--- a/styles/01-styles.scss
+++ b/styles/01-styles.scss
@@ -99,6 +99,7 @@ form {
 button,
 a.button,
 input[type="submit"] {
+    font-size: 12pt;
     background-color: var(--primary);
     border: .4em double var(--primary);
     border-radius: .6em;
@@ -106,7 +107,7 @@ input[type="submit"] {
     padding: .3em .6em;
     color: #fff;
     margin-bottom: .4em;
-
+    text-decoration: none;
     box-shadow: 0px .4em 0 0 var(--primary-dark);
 
     &:active {
diff --git a/views/build.ejs b/views/build.ejs
index f349149..ed5c249 100644
--- a/views/build.ejs
+++ b/views/build.ejs
@@ -18,6 +18,11 @@
             <label>Dependencies</label> <span><%= build.dependencies %></span>
             <label>Start time</label> <span class="to-local-time"><%= build.startTime %></span>
         </div>
+        <% if (!ended) { %>
+        <div>
+            <a href="/build/<%= build.id %>/cancel" class="button">Cancel build</a>
+        </div>
+        <% } %>
         <p><a href="/build/<%= build.id %>/logs">Full logs</a></p>
         <div class="logs" id="logs">
             <% (log || []).forEach(line => { %>