How to debug Cloud deployment problems

Start with the debugging checklist. Work through the checklist by selecting the most appropriate answer for each question until you arrive at a probable fault for the symptoms you’re seeing.

There is also a complete decision tree for the debugging process.

Debugging checklist

Start here: a deployment has not worked as expected

Does the environment pane show a “Last deployment failed” error message?

The Control Panel shows a Last deployment failed message

Open the failed link to see the deployment log. The relevant section will be towards the end, so work backwards from the end. Any error will be clearly stated.

What does the deployment log contain?

Probable fault: temporary problem

Please try again. This is a rare and usually temporary problem. You may need to wait a few minutes for the condition to clear.

The deployment log contains no obvious error

The build process succeeded without errors, creating an image and then releasing containers that passed the all health-checks, but all the same, the site is not working as expected. This should not occur, but can do in certain quite specific circumstances.

Check the environment’s runtime logs.

Do you see any obvious errors in the runtime logs for the environment’s web container?

The runtime log contains no errors

Either the application is failing to write error logs, or some other problem has occurred. Please contact Divio Support.

The runtime log contains errors

The probable cause is a programming issue. The runtime logs should help you understand the nature of this problem.

The deployment log contains an error

The end of the log will generally contain the key error.

Is the error:

Container error: unable to connect to the container

You will see something like:

Trying to connect to internal container http://10.0.0.164:11453/ (0:00:59.666292 with 148 retries)...
connection error.
Unable to connect! Endpoint verification failed.

The load-balancer was unable to connect to each of the environment’s newly-launched containers and obtain a positive HTTP response within 20 seconds of making the connection. The environment’s runtime logs will contain more information about the problem. If the logs don’t contain a traceback revealing a programming error, the most likely issue is that the application was too slow to start up.

Could not find a version that matches [...]

Python project, indicates that a specified dependency cannot be found - typically because two or more of the components in your system have specified incompatible Python dependencies.

For Aldryn Django projects, see How to identify and resolve a dependency conflict.

npm ERR! [...] ERR! /npm-debug.log

Probable fault: A Node error has halted the build.

ReadTimeoutError

This may occasionally occur when our deployment infrastructure is under heavy load. In most cases you can simply try again.

The environment does not show a “Last deployment failed” error

Probable fault: programming error at runtime

Sometimes there is no failed deployment log, but the site fails to start. This is very rare, and is typically caused by a programming error that becomes apparent only at runtime, after basic health-checks have passed.

The error will be shown in the site’s runtime logs, available from the Logs menu in the Control Panel.

Decision tree

This tree represents the logic of the debugging checklist.