Last week, ITS upgraded several Linux servers from Debian Bullseye to Bookworm. As part of this upgrade, Docker was also updated to a newer release. This update removed compatibility for Docker’s long‑deprecated "link" feature, which several of our internal services were still relying on for container‑to‑container communication.
The outage was caused by the continued use of Docker’s legacy link feature, which is not supported in the Docker version included with Debian Bookworm. After the upgrade, containers were unable to establish the expected communication paths, leaving the service non‑functional.
This morning, ITS engineers migrated the affected services to Docker’s modern network‑based communication model, replacing all uses of the disabled link feature. This required development work to adjust service configuration, update scripts, and ensure all components functioned correctly under the newer networking model. All services have now been updated, tested, and brought back online.