title: Spawn containers on ACI using @azure/arm-containerinstance
body: <p>I am working on processing data microservice. I have this microservice dockerized and now I want to deploy it. To achieve it, I am trying to manage containers in Azure Container Instances using Azure Function written in node.js.</p>
  <p>The first thing I wanted to test is spawning containers within a group. My idea was:</p>
  <pre><code>const oldConfig = await client.containerGroups.get(
      'resourceGroup',
      'resourceName'
  );
  
  const response = await client.containerGroups.createOrUpdate(
    'resourceGroup',
    'resourceName',
    {
      osType: oldConfig.osType,
      containers: [
        ...oldConfig.containers,
        {
          name: 'test',
          image: 'hello-world',
          resources: {
            requests: {
              memoryInGB: 1,
              cpu: 1,
            },
          },
        },
      ],
    }
  );
  </code></pre>
  <p>I've added osType, because docs and interface says it's required, but when I do this I receive error 'to update osType you need to remove and create group containers&quot;. When I remove osType, request is successful, but ACI does not change. I cannot recreate whole group upon every new container, because I want them to process jobs and terminate by themselves.</p>