eBPF allows us to build custom programs that run directly within the kernel. This talk explores how eBPF enables observability, security and connectivity tools that no longer need to rely on the sidecar model, and shows how Cilium now supports both sidecar-based and sidecarless Service Mesh. Along the way this talk will clarify some container and kernel concepts so that attendees can leave with a mental model for the pros and cons of sidecar-based or sidecarless approaches.