  Edge and fog computing architectures utilize container technologies in order
to offer a lightweight application deployment. Container images are stored in
registry services and operated by orchestration platforms to download and start
the respective applications on nodes of the infrastructure. During large
application rollouts, the connection to the registry is prone to become a
bottleneck, which results in longer provisioning times and deployment
latencies. Previous work has mainly addressed this problem by proposing
scalable registries, leveraging the BitTorrent protocol or distributed storage
to host container images. However, for lightweight and dynamic edge
environments the overhead of several dedicated components is not feasible in
regard to its interference of the actual workload and is subject to failures
due to the introduced complexity.
  In this paper we introduce a fully decentralized container registry called
EdgePier, that can be deployed across edge sites and is able to decrease
container deployment times by utilizing peer-to-peer connections between
participating nodes. Image layers are shared without the need for further
centralized orchestration entities. The conducted evaluation shows that the
provisioning times are improved by up to 65% in comparison to a baseline
registry, even with limited bandwidth to the cloud.
