Retrieve container logs and events in Azure Container Instances

When you have a misbehaving container, start by viewing its logs with az container logs, and streaming its standard out and standard error with az container attach.

View logs

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

The following is log output from the example task-based container in Run a containerized task in ACI, after having fed it an invalid URL to process:

$ 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 has started, it streams STDOUT and STDERR to your local console.

For example, here is output from the task-based container in Run a containerized task in ACI, after having 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, you need to review the diagnostic information provided by the Azure Container Instances resource provider. To view the events for your container, run the [az container show][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.