Explanation
Using seccomp does not limit a Docker container's access to host resources, such as CPU or memory.
Seccomp is a Linux kernel facility that allows filtering system calls made by a process. It can be used to enhance the security and isolation of a container by restricting its access to certain system calls. However, it does not affect the resource allocation or consumption of a container. References:
https://docs.docker.com/engine/security/seccomp/,
https://www.kernel.org/doc/html/v4.14/userspace-api/seccomp_filter.html

Explanation
This command does create a swarm service that only listens on port 53 using the UDP protocol. The docker service create command creates a new service in a swarm cluster. The --name flag sets the name of the service.
The -p or --publish flag publishes a port or a range of ports to the swarm. The syntax for publishing a port is -p
<published-port>:<target-port>[/protocol]. The protocol can be tcp or udp. If no protocol is specified, tcp is used by default. In this case, the command publishes port 53 on the swarm and maps it to port 53 in the container using the udp protocol. Therefore, this command creates a swarm service that only listens on port 53 using the udp protocol. References: https://docs.docker.com/engine/reference/commandline/service_create/,
https://docs.docker.com/engine/reference/commandline/service_create/#publish-service-ports-externally-to-the-s