Information
Seccomp filtering provides a means for a process to specify a filter for incoming system calls. The default Docker seccomp profile works on whitelist basis and allows 311 system calls blocking all others. It should not be disabled unless it hinders your container application usage.
Rationale:
A large number of system calls are exposed to every userland process with many of them going unused for the entire lifetime of the process. Most of the applications do not need all the system calls and thus benefit by having a reduced set of available system calls. The reduced set of system calls reduces the total kernel surface exposed to the application and thus improvises application security.
Solution
By default, seccomp profiles are enabled. You do not need to do anything unless you want to modify and use the modified seccomp profile.
Impact:
With Docker 1.10 and greater, the default seccomp profile blocks syscalls, regardless of --cap-add passed to the container. You should create your own custom seccomp profile in such cases. You may also disable the default seccomp profile by passing --security-opt=seccomp:unconfined on docker run.
Default Value:
When you run a container, it uses the default profile unless you override it with the --security-opt option.