DocumentationReferenceDebugging an applicationUsing Docker

Using Docker

From time to time you may need to have a look at the internal workings of wolkenkit. As wolkenkit is built on Docker it helps to be familiar with it. Anyway, there are a few recurring situations you will probably find yourself in, so it is useful to have the following commands at hand.

Listing containers

If you need to verify the status of the containers of an application, e.g. to verify whether they are actually running, run:

$ docker ps

Monitoring containers

If you want to continuously monitor which containers are being started and stopped use one of the following commands, depending on your operating system.

On macOS

Run the following command:

$ while :; do clear; docker ps; sleep 1; done

On Linux

Run the following command:

$ watch -n 1 docker ps

Entering a running container

Sometimes it is useful to be able to enter a running container, e.g. to inspect the files within the container. Depending on which container you want to enter, run one of the following commands:

# Write model
$ docker exec -it <application>-core sh

# Read model
$ docker exec -it <application>-broker sh

# Flows
$ docker exec -it <application>-flows sh

To exit from a container, just type exit.

Freeing disk space

If you are using Docker on a virtual machine, the virtual machine may run out of disk space eventually. To free disk space run the following command:

$ docker system prune