Applications are private, and private networking is how they talk to each other, to your databases, and to your servers.
Projects
Every application belongs to a project. Apps in the same project share a private network and can reach each other by name, so a web app can call an API app in the same project without any address wrangling. Apps in different projects cannot reach each other. Your account starts with one default project, which is all most setups need.
Managed databases belong to a project too, which is how an app finds a database it is allowed to use.
Connect one of your own networks
To join an application to one of your own private networks, alongside your servers, open the app and Connect a network. Pick the network, then choose how the app addresses itself on it:
- a static range, where you set a First address and Last address, or
- DHCP, where the network assigns the address.
An application can connect up to 4 private networks. A static range must leave room for the app and must not overlap the addresses your servers, databases or other apps already use on that network.
Connecting a network redeploys the app
Attaching or changing a network redeploys the current release so the new network interface takes effect. It does not rebuild, and it is held behind the health check, so a good release keeps serving until the new one is ready.
Reaching the internet
A private network lets your app reach your other private resources, not the public internet. To give an app outbound internet access without a public address, or to let the internet reach it, put a Cloud Firewall on the network. See Make an application reachable from the internet.