Bind address and port
Which addresses and ports Overcast binds for the AWS API and the web console, how to bind several at once, and what LocalStack's GATEWAY_LISTEN maps onto.
Overcast serves the AWS API on 127.0.0.1:4566 natively and 0.0.0.0:4566 in a
container. OVERCAST_LISTEN and OVERCAST_PORT move it:
OVERCAST_LISTEN=127.0.0.1,172.17.0.1 OVERCAST_PORT=4576 overcast serve| Variable | Default | Sets |
|---|---|---|
OVERCAST_LISTEN | 0.0.0.0 containerised, 127.0.0.1 native | Address(es) the AWS API binds; comma-separate to bind several |
OVERCAST_PORT | 4566 | TCP port for the AWS API |
OVERCAST_UI_PORT | 4567 | Port for the web console; 0 disables it |
GATEWAY_LISTEN (LocalStack) | (none) | Both of the first two at once, as <ip>:<port>[,…] |
Binding more than one address
A comma-separated list is how one instance stays reachable from this machine and from its containers over the Docker bridge, without being on any network the machine is attached to. A wildcard cannot be combined with a specific address, and the web console binds the first address only.
An explicit value always wins over the environment-dependent default in either
direction — OVERCAST_LISTEN=0.0.0.0 restores the native reach from a VM or
another machine. OVERCAST_HOST was renamed to OVERCAST_LISTEN and removed; a
leftover one fails startup naming the replacement rather than being silently
ignored.
GATEWAY_LISTEN
LocalStack’s GATEWAY_LISTEN maps to OVERCAST_LISTEN and OVERCAST_PORT
together, and counts as an explicit bind-address setting. Every entry must share
one port: a value naming two has no single OVERCAST_PORT to become, so startup
fails rather than dropping a bind.
Related
- Running two instances on one host — the other ports, and which of them get out of the way on their own
- Environment variable reference
- Configuration