title: (gcloud.run.deploy) Cloud Run error: Container failed to start. Failed to start and then listen on the port
body: <p>After successfully deploying a container using <code>gcloud builds submit --tag gcr.io/projectname/testserver</code> and then attempting to run <code>gcloud run deploy --image gcr.io/projectname/testserver --platform managed</code> I see this error:</p>
  
  <pre><code>$ gcloud run deploy --image gcr.io/projectname/testserver --platform managed
  Please specify a region:
   // options removed
  
  Service name (testserver):  
  Allow unauthenticated invocations to [testserver] (y/N)?  y
  
  Deploying container to Cloud Run service [testserver] in project [projectname] region [us-central1]
  X Deploying new service... Cloud Run error:
   Container failed to start. Failed to start
   and then listen on the port defined by the
   PORT environment variable. Logs for this r
  evision might contain more information.    
    X Creating Revision... Cloud Run error: C
    ontainer failed to start. Failed to start
     and then listen on the port defined by t
    he PORT environment variable. Logs for th
    is revision might contain more informatio
    n.                                       
    . Routing traffic...                     
    ✓ Setting IAM Policy...                  
  Deployment failed                          
  ERROR: (gcloud.run.deploy) Cloud Run error: Container failed to start. Failed to start and then listen on the port defined by the PORT environment variable. Logs for this revision might contain more information.
  
  </code></pre>
  
  <p>I have a very simple project, all in the root folder:</p>
  
  <pre><code>// Dockerfile
  FROM node:12-slim
  
  # Create app folder
  WORKDIR /usr/src/app
  
  # Install app deps. Copy the lock file
  COPY package*.json ./
  RUN npm install
  
  COPY . ./
  CMD ["node", "testServer.js"]
  </code></pre>
  
  <pre><code>// testServer.js
  const Koa = require("koa");
  const koa = new Koa();
  
  koa.get('/', async ctx =&gt; {
    ctx.body = "Koa server running"
  });
  
  const port = process.env.PORT || 8080;
  
  koa.listen(port);
  
  </code></pre>
  
  <p>Anyone know what's causing this? Been trying to solve it since yesterday and now even with this minimal project it seems to be having issues.</p>