Explanation
Using 'docker service inspect http' does not enable you to view the list of historical tasks for this service. The docker service inspect command shows low-level information about one or more services, such as their configuration, replicas, networks, endpoints, etc. It does not show the history of tasks that have been run by the service. To view the list of historical tasks for this service, you need to use 'docker service ps http'.
References: https://docs.docker.com/engine/reference/commandline/service_inspect/,
https://docs.docker.com/engine/reference/commandline/service_ps/

Explanation
SELinux could be blocking the operation of setting the system time from inside a Docker container. SELinux is a security mechanism that enforces mandatory access control (MAC) policies on Linux systems. It restricts the actions that processes can perform based on their security contexts, such as user, role, type, and level. By default, SELinux prevents Docker containers from accessing or modifying the host's system time, as this could pose a security risk or cause inconsistency. To allow Docker containers to set the system time, SELinux needs to be configured with the appropriate permissions or labels, or disabled altogether. However, this is not recommended, as it could compromise the security and stability of the system. References:
* Change system date time in Docker containers without impacting host
* Change Date Inside a Docker Container
* How to Handle Timezones in Docker Containers
* 5 ways to change time in Docker container
* How to set system time dynamically in a Docker container

Explanation
This is how they should be distributed across three datacenters or availability zones, because having an even distribution of managers across datacenters or availability zones ensures that the swarm can survive the loss of any one datacenter or availability zone and maintain quorum. According to the official documentation, managers should be distributed evenly across datacenters or availability zones to ensure that the swarm can survive the loss of any one datacenter or availability zone.
References: https://docs.docker.com/engine/swarm/admin_guide/#add-manager-nodes-for-fault-tolerance

Explanation
Running docker engine activate does upgrade Docker Engine CE to Docker Engine EE. The docker engine activate command is a convenience script that automates the process of uninstalling Docker Engine CE and installing Docker Engine EE on supported platforms. It requires an activation token or license file that can be obtained from Docker Hub or Docker Store. References:
https://docs.docker.com/engine/install/centos/#upgrade-docker-after-using-the-convenience-script,
https://docs.docker.com/engine/install/ubuntu/#upgrade-docker-after-using-the-convenience-script,
https://docs.docker.com/engine/install/debian/#upgrade-docker-after-using-the-convenience-script