Containers, a pinnacle of fast and secure deployment or a panacea of false security? In recent years Linux containers have developed from an insecure and loose collection of Linux kernel namespaces to a production-ready OS virtualization stack. In this talk, the audience will first learn the basics of how containers function, understanding namespaces, capabilities and cgroups in order to see how Linux containers and the supporting kernel features can offer an effective application and system sandboxing solution yet to be widely deployed or adopted. Understanding LXC or Docker use, weaknesses and security for PaaS and application sandboxing is only the beginning. Leveraging container technologies is rapidly becoming popular within the modern PaaS and devops world but little has been publicly discussed in terms of actual security risks or guarantees. Understanding prior container vulnerabilities or escapes, and current risks or pitfalls in major public platforms will be explored in this talk. I'll cover methods to harden containers against future attacks and common mistakes to avoid when using systems such as LXC and Docker. This will also include an analysis and discussion of techniques such as Linux kernel hardening, reduced capabilities, Mandatory Access Controls (MAC), the User kernel namespace and seccomp-bpf (syscall filtering); all of which help actually contain containers. The talk will end on some methods for creating minimal, highly-secure containers and end on where containers are going and why they might show up where you least expect them.