edge:: Enables communication through HTTP between the proxy and Keycloak.
This mode is suitable for deployments with a highly secure internal network where the reverse proxy keeps a secure connection (HTTP over TLS) with clients while communicating with Keycloak using HTTP.
Some Keycloak features rely on the assumption that the remote address of the HTTP request connecting to Keycloak is the real IP address of the clients machine.
If this header is incorrectly configured, rogue clients can set this header and trick Keycloak into thinking the client is connected from a different IP address than the actual address.
Keycloak assumes it is exposed through the reverse proxy under the same context path as Keycloak is configured for. By default Keycloak is exposed through the root (`/`), which means it expects to be exposed through the reverse proxy on `/` as well.
You can use `hostname-path` or `hostname-url` in these cases, for example using `--hostname-path=/auth` if Keycloak is exposed through the reverse proxy on `/auth`.
Alternatively you can also change the context path of Keycloak itself to match the context path for the reverse proxy using the `http-relative-path` option, which will change the context-path of Keycloak itself to match the context path used by the reverse proxy.
By default, Keycloak needs to know under which hostname it will be called. If your reverse proxy is configured to check for the correct hostname, you can set Keycloak to accept any hostname.
Typical cluster deployment consists of the load balancer (reverse proxy) and 2 or more Keycloak servers on private network.
For performance purposes, it may be useful if load balancer forwards all requests related to particular browser session to the same Keycloak backend node.
The reason is, that Keycloak is using Infinispan distributed cache under the covers for save data related to current authentication session and user session.
The Infinispan distributed caches are configured with two owners by default. That means that particular session is primarily stored on two cluster nodes and the other nodes need to lookup the session remotely if they want to access it.
For example if authentication session with ID 123 is saved in the Infinispan cache on node1, and then node2 needs to lookup this session, it needs to send the request to node1 over the network to return the particular session entity.
It is beneficial if particular session entity is always available locally, which can be done with the help of sticky sessions. The workflow in the cluster environment with the public frontend load balancer and two backend Keycloak nodes can be like this:
* User sends initial request to see the Keycloak login screen
* This request is served by the frontend load balancer, which forwards it to some random node (eg. node1). Strictly said, the node doesn't need to be random, but can be chosen according to some other criterias (client IP address etc). It all depends on the implementation and configuration of underlying load balancer (reverse proxy).
* Infinispan distributed cache assigns the primary owner of the session based on the hash of session ID. See Infinispan documentation for more details around this. Let's assume that Infinispan assigned node2 to be the owner of this session.
* Keycloak creates the cookie AUTH_SESSION_ID with the format like <session-id>.<owner-node-id> . In our example case, it will be 123.node2 .
* Response is returned to the user with the Keycloak login screen and the AUTH_SESSION_ID cookie in the browser
From this point, it is beneficial if load balancer forwards all the next requests to the node2 as this is the node, who is owner of the authentication session with ID 123 and hence Infinispan can lookup this session locally. After authentication is finished, the authentication session is converted to user session, which will be also saved on node2 because it has same ID 123 .
The sticky session is not mandatory for the cluster setup, however it is good for performance for the reasons mentioned above. You need to configure your loadbalancer to sticky over the AUTH_SESSION_ID cookie. How exactly do this is dependent on your loadbalancer.
If your proxy supports session affinity without processing cookies from backend nodes, you should set the `spi-sticky-session-encoder-infinispan-should-attach-route` option
to `false` in order to avoid attaching the node to cookies and just rely on the reverse proxy capabilities.
By default, the administration console URLs are created solely based on the requests to resolve the proper scheme, host name, and port. For instance,
if you are using the `edge` proxy mode and your proxy is misconfigured, backend requests from your TLS termination proxy are going to use plain HTTP and potentially cause the administration
console from being accessible because URLs are going to be created using the `http` scheme and the proxy does not support plain HTTP.
In order to proper expose the administration console, you should make sure that your proxy is setting the `X-Forwarded-*` headers herein mentioned in order
to create URLs using the scheme, host name, and port, being exposed by your proxy.
As it's true that the `js` path is needed for internal clients like the account console, it's good practice to use `keycloak.js` from a JavaScript package manager like npm or yarn for your external clients.
When the proxy is configured as a TLS termination proxy the client certificate information can be forwarded to the server through specific HTTP request headers and then used to authenticate
clients. You are able to configure how the server is going to retrieve client certificate information depending on the proxy you are using.
The server supports some of the most commons TLS termination proxies such as:
The NGINX SSL/TLS module does not expose the client certificate chain. Keycloak's NGINX certificate lookup provider rebuilds it by using the Keycloak truststore.
