...
Note, you can customize the MQTT user name and password using the mqtt_user and mqtt_pwd variables in the docker/playbook/group_vars/all/mqtt.yml file. By default the user name is "edge" and the password "edgemqtt". These credentials must be used if you want to, for example, use the mosquitto_sub command to monitor incoming MQTT messages from the edge nodes.
...
be used if you want to, for example, use the mosquitto_sub command to monitor incoming MQTT messages from the edge nodes.
Creating the Docker Registry
This blueprint sets up a private Docker registry on the master node to hold all the images which will be downloaded to the edge nodes. The following command with start the registry. This command also creates and installs a cryptographic key that is used to identify the registry to the edge nodes.
ansible-playbook -i ./hosts start_registry.yml --ask-become-pass
Once this command has been run the registry will run as a service and will automatically restart if the master node reboots for some reason. If you need to stop the registry or clear its contents, see the instructions in the Stopping and Clearing the Docker Registry section of the Uninstall Guide.
Note that if you stop and restart the registry new keys will be generated and you will need to run the edge_install.yml playbook again to copy them to the edge nodes.
Preparing Edge Nodes
Add an administrative account to all the edge nodes. This account will be used by the deploy node when it needs to run commands directly on the edge nodes (e.g. for installing base software, or for joining or leaving the cluster). The following commands run on each edge node will add a user account named "edge" and add it to the group of users with sudo privileges.
...
Removing Edge Nodes
Stopping Kubernetes
Stopping and Clearing the Docker Registry
Uninstalling Software Components
...