Explanation
Uninstalling 'docker-ce' package before installing 'docker-ee' package does upgrade Docker Engine CE to Docker Engine EE. Docker Engine CE is the free and open source edition of Docker Engine, while Docker Engine EE is the enterprise-ready edition that includes additional features and support. To upgrade from CE to EE, you need to uninstall the 'docker-ce' package and its dependencies, and then install the 'docker-ee' package from the Docker repository. References:
https://docs.docker.com/engine/install/centos/#upgrade-docker-after-using-the-convenience-script,
https://docs.docker.com/engine/install/centos/#install-using-the-repository

Explanation
Using 'docker ls -a' does not list all nodes in a swarm cluster from the command line. The docker ls command is not a valid command. To list containers, you need to use 'docker container ls' or 'docker ps'. To list images, you need to use 'docker image ls' or 'docker images'. To list nodes in a swarm cluster, you need to use
'docker node ls'. References: https://docs.docker.com/engine/reference/commandline/container_ls/,
https://docs.docker.com/engine/reference/commandline/image_ls/,
https://docs.docker.com/engine/reference/commandline/node_ls/

Explanation
pid is not a Linux kernel namespace that is disabled by default and must be enabled at Docker engine runtime to be used. pid is a Linux kernel namespace that provides process isolation for containers. It ensures that processes in one container cannot see or signal processes in another container or on the host system. pid is enabled by default for Docker containers and does not require any special flag or option to be used. However, you can disable pid isolation for a container by using --pid host option when creating or running a container.
This option connects the container to the host's pid namespace and allows the container to see and signal processes on the host system. References: https://docs.docker.com/engine/reference/run/#pid-settings-pid,
https://en.wikipedia.org/wiki/Linux_namespaces#Process_ID_(pid)

Explanation
Using docker system events --filter splunk does not configure a Docker container to export container logs to the logging solution. The docker system events command shows real-time events from the server, such as container creation, image deletion, network connection, etc. It does not show or export container logs to any external service. The --filter option allows filtering events by type, action, image, container, etc., but it does not accept splunk as a valid filter value. References:
https://docs.docker.com/engine/reference/commandline/system_events/,
https://docs.docker.com/config/containers/logging/