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Containers

The Containers page surfaces the Docker containers running on the GenMaster host so you can see their state at a glance and take basic actions (start, restart, view logs) without dropping into a terminal. It's a lightweight Portainer-style UI scoped to just GenMaster's stack.

Containers page overview with all 9 containers

Initial load can take 10–15 seconds

On first navigation, the page shows a "Taking attendance..." (then "Shaking the containers to see what rattles...") spinner while it queries the Docker daemon. If the list is still empty after 30 seconds, click Refresh in the top-right.

Top stat row

Card Meaning
Total All containers visible to the Docker daemon.
Running Currently up.
Stopped Defined but not running.
Unhealthy Running but a healthcheck is failing.

Filter bar

  • Status filter dropdown — All Statuses, Running Only, Stopped Only.
  • Refresh (top-right) — re-polls the Docker daemon. The page also auto-refreshes on a timer.
  • Expand All (right side, above the list) — opens the detail panel on every row at once.

The "Showing X of Y containers" label tells you how many match your current filter.

The container list

A two-column grid of containers. Each row shows:

  • The chevron (>) on the left — click to expand the detail panel inline.
  • A status icon (green checkmark for healthy, red triangle for unhealthy).
  • The container name (e.g. genmaster_nginx) and image tag (e.g. nginx:alpine) below it.
  • Status badges: Running / Stopped plus optionally healthy / unhealthy.

For the GenMaster stack, the containers you'll typically see are:

Container name Image Role
genmaster rjsears/genmaster:latest Backend API (FastAPI). State machine, scheduler, Victron GPIO listener.
genmaster_nginx nginx:alpine Reverse proxy, TLS termination.
genmaster_db postgres:16-alpine PostgreSQL — state, run history, config.
genmaster_redis redis:7-alpine Cache and websocket pub/sub.
genmaster_host_tools rjsears/genmaster-host-tools:latest Privileged sidecar for whitelisted host commands (reboot, shutdown, network changes).
genmaster_tailscale tailscale/tailscale:latest Optional Tailscale daemon.
genmaster_cloudflared cloudflare/cloudflared:latest Optional Cloudflare Tunnel.
genmaster_portainer portainer/portainer-ce:latest Optional Portainer UI.
genmaster_certbot certbot/dns-cloudflare:latest Let's Encrypt certificate renewal (DNS-01 challenge).

Expanded container detail

Click a row's chevron (or Expand All) to see live stats and action buttons for that container.

Expanded container row showing live stats and action buttons

The expanded panel shows:

Element Meaning
Recreate Container Tears down and re-creates the container from the same image. Use after pulling a new image tag or after changing .env values that aren't picked up by a simple restart.
Uptime Time since the container last started.
CPU Current CPU usage as a percentage.
Memory Current RAM usage in MB.
Network Cumulative network I/O since container start (download + upload).
Memory Usage bar Visual indicator of memory percentage relative to the host's RAM.
Stop / Start Graceful stop or start. The label switches based on current state.
Restart docker restart — issues a stop, then a start.
Logs Opens the Logs dialog (see below).

Logs dialog

Clicking Logs opens a modal with live container output.

Logs dialog for genmaster_nginx

Control Behavior
Lines How many recent log lines to show (default 200; common picks: 50, 100, 200, 500, 1000).
Since Restrict to lines newer than this duration or timestamp (1h, 30m, 2024-01-01, etc.).
Follow Toggle live tail — new lines stream in as the container produces them.
Refresh Re-fetch logs immediately.
Search logs... Filter the displayed lines client-side.
Showing N lines (footer) How many lines are currently rendered.
Close Dismiss the dialog.

The log content area is monospaced and scrollable. Application logs, access logs (for nginx), and stderr all appear here interleaved.

Sensitive data

Container logs frequently include IP addresses, request paths, and occasionally tokens or session IDs. Mask before sharing screenshots externally.

Critical Container Warnings

Stopping certain containers can take down the GenMaster web UI or sever your remote access. To prevent accidental shutdown, GenMaster intercepts the Stop action on any container deemed critical and shows a Danger Zone confirmation dialog. The dialog spells out exactly what you'll lose and how to bring it back.

Connectivity-loss warning (e.g. genmaster_nginx)

Critical container warning when stopping genmaster_nginx

When you click Stop on a container that hosts the web UI itself (such as genmaster_nginx), the warning explains:

  • What happens: "This action may cause the loss of connectivity to GenMaster!" — you'll lose access to this very page.
  • How to recover: SSH to the docker host and run docker compose up -d genmaster_nginx from the pizero_generator_control directory.
  • Cancel safely returns you to the container list with no action taken.
  • SHUTDOWN (red, destructive) confirms the stop.

Remote-access warning (e.g. genmaster_tailscale)

Critical container warning when stopping genmaster_tailscale

When you click Stop on the Tailscale container, the warning is more nuanced — you may still be able to reach GenMaster via Cloudflare or your local network, but Tailscale-only access will go away:

"This action may cause the loss of connectivity to GenMaster host server! If you stop this container, you may lose access to your GenMaster docker host if you are using Tailscale exclusively for connectivity. GenMaster will still be accessible via CloudFlare or from within your network. You can start it again by running: docker compose up -d genmaster_tailscale from the pizero_generator_control directory on the docker host."

Which containers trigger this dialog

Container Why it's critical
genmaster Stops the API — UI loses its data source.
genmaster_nginx Stops the web server — UI becomes unreachable from any path.
genmaster_db Backend will error on the next DB query; closing in-flight requests.
genmaster_redis Cache loss; websocket events stop firing.
genmaster_cloudflared Public Cloudflare-Tunnel access goes away.
genmaster_tailscale Tailscale-VPN access goes away.

Non-critical containers (e.g. genmaster_certbot, genmaster_portainer, genmaster_host_tools) typically stop without a confirmation dialog.

Don't stop genmaster_db while genmaster is running

The API will error and close in-flight requests. Stop genmaster first, then genmaster_db, and reverse the order to restart.

When to use this page vs. SSH

The Containers tab is great for:

  • Quick health checks ("is everything green?").
  • Restarting a specific service after a config change.
  • Tailing logs without opening a shell.
  • Recreating a container after a docker pull.

For deeper work — docker compose down, image rebuilds, mounting different volumes, or changing the compose file — SSH into the host and use docker compose directly.

What's next