Retrieve container logs and events in Azure Container Instances

When you have a misbehaving container in Azure Container Instances, start by viewing its logs with az container logs and streaming its standard out and standard error with az container attach. You can also view logs and events for container instances in the Azure portal, or send log and event data for container groups to Azure Monitor logs.

View logs

To view logs from your application code within a container, you can use the az container logs command.

The following sample output is log output from the example task-based container in Set the command line in a container instance, after being provided an invalid URL using a command-line override:

az container logs --resource-group myResourceGroup --name mycontainer

Traceback (most recent call last):
  File "wordcount.py", line 11, in <module>
    urllib.request.urlretrieve (sys.argv[1], "foo.txt")
  File "/usr/local/lib/python3.6/urllib/request.py", line 248, in urlretrieve
    with contextlib.closing(urlopen(url, data)) as fp:
  File "/usr/local/lib/python3.6/urllib/request.py", line 223, in urlopen
    return opener.open(url, data, timeout)
  File "/usr/local/lib/python3.6/urllib/request.py", line 532, in open
    response = meth(req, response)
  File "/usr/local/lib/python3.6/urllib/request.py", line 642, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/local/lib/python3.6/urllib/request.py", line 570, in error
    return self._call_chain(*args)
  File "/usr/local/lib/python3.6/urllib/request.py", line 504, in _call_chain
    result = func(*args)
  File "/usr/local/lib/python3.6/urllib/request.py", line 650, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)
urllib.error.HTTPError: HTTP Error 404: Not Found

Attach output streams

The az container attach command provides diagnostic information during container startup. Once the container starts, it streams STDOUT and STDERR to your local console.

For example, here's output from the task-based container in Set the command line in a container instance, after being supplied a valid URL of a large text file to process:

az container attach --resource-group myResourceGroup --name mycontainer

Container 'mycontainer' is in state 'Unknown'...
Container 'mycontainer' is in state 'Waiting'...
Container 'mycontainer' is in state 'Running'...
(count: 1) (last timestamp: 2019-03-21 19:42:39+00:00) pulling image "mcr.microsoft.com/azuredocs/aci-wordcount:latest"
Container 'mycontainer1' is in state 'Running'...
(count: 1) (last timestamp: 2019-03-21 19:42:39+00:00) pulling image "mcr.microsoft.com/azuredocs/aci-wordcount:latest"
(count: 1) (last timestamp: 2019-03-21 19:42:52+00:00) Successfully pulled image "mcr.microsoft.com/azuredocs/aci-wordcount:latest"
(count: 1) (last timestamp: 2019-03-21 19:42:55+00:00) Created container
(count: 1) (last timestamp: 2019-03-21 19:42:55+00:00) Started container

Start streaming logs:
[('the', 22979),
 ('I', 20003),
 ('and', 18373),
 ('to', 15651),
 ('of', 15558),
 ('a', 12500),
 ('you', 11818),
 ('my', 10651),
 ('in', 9707),
 ('is', 8195)]

Get diagnostic events

If your container fails to deploy successfully, review the diagnostic information provided by the Azure Container Instances resource provider. To view the events for your container, run the az container show command:

az container show --resource-group myResourceGroup --name mycontainer

The output includes the core properties of your container, along with deployment events (shown here truncated):

{
  "containers": [
    {
      "command": null,
      "environmentVariables": [],
      "image": "mcr.microsoft.com/azuredocs/aci-helloworld",
      ...
        "events": [
          {
            "count": 1,
            "firstTimestamp": "2019-03-21T19:46:22+00:00",
            "lastTimestamp": "2019-03-21T19:46:22+00:00",
            "message": "pulling image \"mcr.microsoft.com/azuredocs/aci-helloworld\"",
            "name": "Pulling",
            "type": "Normal"
          },
          {
            "count": 1,
            "firstTimestamp": "2019-03-21T19:46:28+00:00",
            "lastTimestamp": "2019-03-21T19:46:28+00:00",
            "message": "Successfully pulled image \"mcr.microsoft.com/azuredocs/aci-helloworld\"",
            "name": "Pulled",
            "type": "Normal"
          },
          {
            "count": 1,
            "firstTimestamp": "2019-03-21T19:46:31+00:00",
            "lastTimestamp": "2019-03-21T19:46:31+00:00",
            "message": "Created container",
            "name": "Created",
            "type": "Normal"
          },
          {
            "count": 1,
            "firstTimestamp": "2019-03-21T19:46:31+00:00",
            "lastTimestamp": "2019-03-21T19:46:31+00:00",
            "message": "Started container",
            "name": "Started",
            "type": "Normal"
          }
        ],
        "previousState": null,
        "restartCount": 0
      },
      "name": "mycontainer",
      "ports": [
        {
          "port": 80,
          "protocol": null
        }
      ],
      ...
    }
  ],
  ...
}

Next steps

Learn how to troubleshoot common container and deployment issues for Azure Container Instances.

Learn how to send log and event data for container groups to Azure Monitor logs.