Bluefin Developer Mode#

Developer Mode (bluefin-dx) is Bluefin's opt-in developer experience layer. It adds cloud-native tooling — Docker Engine, Podman Desktop, devcontainer support, virtualization, and performance profiling tools — on top of the base Bluefin image 1. The philosophy is explicit OS/tooling separation: development happens in containers, VMs, or user-space (Homebrew), not via host packages.

Architecture note: There is no longer a separate -dx OCI image that users rebase into. Developer mode is activated in-place via ujust devmode — a wizard that installs tooling and configures group membership without an image switch. 2

Enabling Developer Mode#

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Bluefin LTS users skip Step 2 — group membership is handled automatically. 4

ujust toggle-devmode is a maintained alias for ujust devmode. 5

Note: On the current in-place wizard (bctl-based), group membership may be handled during the wizard run itself, making Step 2 unnecessary. The two-step process applies to systems without bctl installed.

How the wizard works#

When bctl (bluefinctl) is installed (default on current images), ujust devmode delegates to bctl --screen developer for a richer TUI. On systems without bctl, it falls back to an interactive gum choose UI. 6

The wizard:

• Presents tool groups (Docker, Podman, Virtualization, IDE, CLI Editors) as a selection screen
• Writes a ~/.config/bluefin/devmode marker to detect re-runs
• Manages group membership via pkexec in a single pass — no need for a separate ujust dx-group invocation post-wizard 2

What's Included#

Full feature reference: docs.projectbluefin.io/bluefin-dx 7

Optional installs:

• ujust jetbrains-toolbox — JetBrains Toolbox (manages IDEs in $HOME, independent of image)
• ujust bbrew → k8s-tools — Kubernetes toolset (kubectl, helm, k9s, kind, etc.)
• ujust cncf — browser/installer for 89 CNCF projects 8

Dakota and the -dx Image Removal#

Dakota (the Bluefin build stream) previously had a devmode override that attempted to rebase to a ghcr.io/projectbluefin/dakota-dx:latest image — which was never published. This caused ujust devmode to fail with a 403 Forbidden error on Dakota systems. 9

The override was removed in dakota#1028 (June 2026). Dakota is developer-experience-on by default and delegates to common's in-place wizard. 9

Legacy Migration Paths#

ublue-os → projectbluefin (LTS users)#

Users on the old ghcr.io/ublue-os/bluefin-lts or bluefin-dx images are migrated automatically via a systemd service shipped in the last weekly build of the old image. The service runs bootc switch non-destructively and leaves an MOTD notice for the next reboot. 10

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Former -dx users land on the base bluefin-lts:stable image and re-enable developer mode with ujust devmode after the first reboot — the MOTD includes this reminder. 12

Manual switch#

sudo bootc switch ghcr.io/projectbluefin/bluefin-lts:lts --enforce-container-sigpolicy

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Note: Rebasing between the Fedora-based Bluefin and the CentOS-based Bluefin LTS families is not a supported upgrade path — treat those as fresh installs. 14

Key Source References#