One important element of keeping your system secure is making sure you keep it up to date with all the latest security patches. This approach needs to be applied to your application code and your server's operating system and applications, and, if you are using Docker, you also need to ensure that your containers are up to date to ensure you are free from vulnerabilities.
One of the simplest ways to keep your containers secure is to ensure that you build and deploy them regularly. Quite often, if a service is not under active development, then it may not be deployed to production for months on end. Because of this problem, you may be patching host-level application libraries such as OpenSSL, but because of the application isolation that a container gives, you may have vulnerable binaries at a container level. The simplest way of keeping things up to date is to run a regular build and deploy even if the application code does not change. You also need to ensure...