What is ContainerNursery?

ContainerNursery is a self-hosted reverse proxy written in Node.js that puts Docker containers to sleep when idle and wakes them when new HTTP requests arrive. It connects to the Docker daemon via /var/run/docker.sock. Key capabilities include automatic container start/stop based on configurable timeout, WebSocket-aware stopping, a loading page that auto-reloads when the target is ready, support for multiple domains and containers per host, HTTPS proxying to containers, CPU-aware stopping prevention, and customizable ready-check HTTP methods. Configuration uses a config.yml file with live reload, plus environment variables for logging and port. The project recommends running behind another reverse proxy for HTTPS. It is distributed as a Docker image on ghcr.io.

Should you self-host ContainerNursery?

ContainerNursery scores 47/100 on selfhost.directory (how scoring works) and ranks #4 of 5 in Docker Management. It has 256 GitHub stars.

There was no stable release in the past 12 months, so check the repository's recent activity before you rely on it.

Setup is moderate: expect some configuration beyond a single command. An official Docker image is available. It is MIT-licensed and written mostly in Typescript.

Its closest alternative on selfhost.directory is dockge (76/100, 24 700 stars). It scores higher overall, so compare the two before you pick. See ContainerNursery vs dockge side by side.

Features

Automatic container start/stop
CPU-aware stopping prevention
Customizable ready-check HTTP method
HTTPS proxying to containers
Live configuration reload
Loading page with auto-reload
Multiple containers per host
Multiple domains per proxy host
WebSocket-aware stopping

How to configure ContainerNursery

CN_LOG_JSONfalseIf set to true all logging is done in a machine readable format (JSON)
If set to true all logging is done in a machine readable format (JSON)
values: true / false
CN_LOG_LEVELinfoSets the minimum log level. Log entries below this importance level won't be printed to the console
Sets the minimum log level. Log entries below this importance level won't be printed to the console
values: debug / info / warn / error
CN_PORT80Sets the port ContainerNursery listens on for new http connections. The proxyListeningPort option in the config.yml file takes precedence if both are set
Sets the port ContainerNursery listens on for new http connections. The proxyListeningPort option in the config.yml file takes precedence if both are set
values: integer
containerNameArray or string of which container(s) (by name or id) to start and stop. ContainerNursery can start and stop multiple containers for a single proxy host
Array or string of which container(s) (by name or id) to start and stop. ContainerNursery can start and stop multiple containers for a single proxy host
values: array or string
displayNameThe name (of the service) that should be displayed on the waiting page
The name (of the service) that should be displayed on the waiting page
values: string
domainArray or string containing domain(s) to listen for (equals the host header)
Array or string containing domain(s) to listen for (equals the host header)
values: array or string
proxyHostDomain / IP of container (use custom Docker bridge networks for dynDNS using the name of the container)
Domain / IP of container (use custom Docker bridge networks for dynDNS using the name of the container)
values: string
proxyListeningPort80The port ContainerNursery should listen on for new http connections
The port ContainerNursery should listen on for new http connections
values: integer
proxyPortPort on which the containers webserver listens on
Port on which the containers webserver listens on
values: integer
proxyUseCustomMethodCan be set to a HTTP method (HEAD, GET, ...) which should be used for the ready check
Can be set to a HTTP method (HEAD, GET, ...) which should be used for the ready check
values: HTTP method string
proxyUseHttpsfalseBoolean indicating if the proxy should use HTTPS to connect to the container. Defaults to false. This should only be used if the container only accepts HTTPS requests
Boolean indicating if the proxy should use HTTPS to connect to the container. Defaults to false. This should only be used if the container only accepts HTTPS requests
values: true / false
stopOnTimeoutIfCpuUsageBelowIf set, prevents the container from stopping when reaching the configured timeout if the averaged CPU usage of the main container is above this value
If set, prevents the container from stopping when reaching the configured timeout if the averaged CPU usage of the main container is above this value
values: integer (percentage 0-100*core count)
timeoutSecondsSeconds after which the container should be stopped. The internal timeout gets reset to this configured value every time a new HTTP request is made, or when the timer runs out while a Websocket connection is still active
Seconds after which the container should be stopped. The internal timeout gets reset to this configured value every time a new HTTP request is made, or when the timer runs out while a Websocket connection is still active
values: integer