Requirements

The installer stops without Docker, Compose, 2 GiB of RAM or a free port, and warns when memory or disk is below the recommendation. On an existing installation, ./railhook doctor checks Docker, Compose and the configuration on disk.

Host

Resource	Requirement
Docker	Docker Engine 20.10 or newer, with the daemon running and reachable by your user
Compose	Compose v2, as `docker compose` or the standalone `docker-compose`
Memory	About 4 GiB. Between 2 and 4 GiB the installer warns you to expect swapping; below 2 GiB it stops
Disk	At least 5 GiB free for the images, plus room for the database. The installer warns below 5 GiB
Tools	`curl` and `openssl`, which the installer uses to download files and generate secrets

The stack runs two JVMs, a database and a cache. The default memory limits per container, each set in .env, add up to about 3.1 GiB:

Service	Limit	Variable
`api`	768m	`API_MEMORY_LIMIT`
`worker`	768m	`WORKER_MEMORY_LIMIT`
`postgres`	1G	`POSTGRES_MEMORY_LIMIT`
`redis`	512m	`REDIS_MEMORY_LIMIT`
`ui`	128m	`UI_MEMORY_LIMIT`

Ports

Port	When
`80`	Without a domain. Change it with `--port` if something else already holds it
`80` and `443`	With `--domain`. Both must be free, because the TLS terminator takes them
`8080` on `127.0.0.1`	With `--domain --behind-proxy`. Your proxy keeps 80 and 443. Change it with `--port`

Nothing else is published to the host.

Network

Inbound: the one port above, from wherever your users and your webhook providers are.
Outbound, to install and upgrade: raw.githubusercontent.com and api.github.com for the release files, and ghcr.io for the images.
Outbound, to deliver: HTTP and HTTPS to your endpoints and destinations, on whatever ports they use.

Kubernetes

The Helm chart needs Kubernetes 1.24+ and Helm 3.8+, plus PostgreSQL 16+ and Redis 7+ that you supply. See Kubernetes.