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+# Keycloak Integration (OIDC) with SeaweedFS S3 Gateway
+
+This guide shows how to integrate Keycloak (OpenID Connect) with SeaweedFS S3 Gateway using the advanced IAM and STS configuration. It supports both:
+
+- Direct OIDC authentication to S3 with Bearer tokens
+- OIDC to STS role assumption using trust policies and role mapping
+
+## Prerequisites
+
+- A running Keycloak server and a realm (e.g. `seaweedfs`)
+- A Keycloak client (e.g. `seaweedfs-s3`) created in that realm
+- SeaweedFS with advanced IAM enabled via `-iam.config`
+
+## Step 1: Configure Keycloak
+
+1) Create a client
+- Client ID: `seaweedfs-s3`
+- Access Type: public or confidential (confidential requires a client secret)
+- Standard Flow: enabled (for browser login flows)
+
+2) Add role/group claims to tokens
+- Add a mapper of type "Group Membership" or "User Realm Role" that puts roles/groups into a top-level claim:
+  - Claim name: `groups` (recommended) or `roles`
+  - Add to ID token: true
+  - Add to Access token: true
+
+3) Confirm OIDC discovery
+- Open your realm discovery document and note the issuer and certs endpoints (Keycloak Quarkus defaults):
+  - Issuer: `https://KEYCLOAK/realms/<realm>`
+  - JWKS (certs): `https://KEYCLOAK/realms/<realm>/protocol/openid-connect/certs`
+  - UserInfo: `https://KEYCLOAK/realms/<realm>/protocol/openid-connect/userinfo`
+
+Note: For older Keycloak distributions, issuer may include `/auth` in the path.
+
+## Step 2: Prepare SeaweedFS IAM config
+
+Create an IAM configuration JSON file (e.g. `/etc/seaweed/iam_keycloak.json`) and reference it with `weed s3 -iam.config=...`.
+
+Minimal example with Keycloak OIDC provider, role mapping, roles, and policies:
+
+```json
+{
+  "sts": {
+    "tokenDuration": "1h",
+    "maxSessionLength": "12h",
+    "issuer": "seaweedfs-sts",
+    "signingKey": "c2Vhd2VlZGZzLXNpZ25pbmcta2V5LTMyLWNoYXJzLWxvbmc="
+  },
+  "providers": [
+    {
+      "name": "keycloak",
+      "type": "oidc",
+      "enabled": true,
+      "config": {
+        "issuer": "https://KEYCLOAK/realms/seaweedfs",
+        "clientId": "seaweedfs-s3",
+        "clientSecret": "<optional-if-confidential>",
+        "jwksUri": "https://KEYCLOAK/realms/seaweedfs/protocol/openid-connect/certs",
+        "userInfoUri": "https://KEYCLOAK/realms/seaweedfs/protocol/openid-connect/userinfo",
+        "scopes": ["openid", "profile", "email", "roles", "groups"],
+        "roleMapping": {
+          "rules": [
+            { "claim": "groups", "value": "admins", "role": "arn:seaweed:iam::role/S3AdminRole" },
+            { "claim": "groups", "value": "developers", "role": "arn:seaweed:iam::role/S3WriteRole" }
+          ],
+          "defaultRole": "arn:seaweed:iam::role/S3ReadOnlyRole"
+        }
+      }
+    }
+  ],
+  "policies": [
+    {
+      "name": "S3ReadOnlyPolicy",
+      "document": {
+        "Version": "2012-10-17",
+        "Statement": [
+          { "Effect": "Allow", "Action": ["s3:List*", "s3:Get*"], "Resource": ["*"] }
+        ]
+      }
+    },
+    {
+      "name": "S3WritePolicy",
+      "document": {
+        "Version": "2012-10-17",
+        "Statement": [
+          { "Effect": "Allow", "Action": ["s3:List*", "s3:Get*", "s3:Put*", "s3:DeleteObject"], "Resource": ["*"] }
+        ]
+      }
+    },
+    {
+      "name": "S3AdminPolicy",
+      "document": {
+        "Version": "2012-10-17",
+        "Statement": [
+          { "Effect": "Allow", "Action": ["s3:*"] , "Resource": ["*"] }
+        ]
+      }
+    }
+  ],
+  "roles": [
+    {
+      "roleName": "S3ReadOnlyRole",
+      "roleArn": "arn:seaweed:iam::role/S3ReadOnlyRole",
+      "attachedPolicies": ["S3ReadOnlyPolicy"],
+      "trustPolicy": {
+        "Version": "2012-10-17",
+        "Statement": [
+          {
+            "Effect": "Allow",
+            "Principal": { "Federated": "*" },
+            "Action": ["sts:AssumeRoleWithWebIdentity"],
+            "Condition": {
+              "StringEquals": { "seaweed:Issuer": "https://KEYCLOAK/realms/seaweedfs" }
+            }
+          }
+        ]
+      }
+    },
+    {
+      "roleName": "S3WriteRole",
+      "roleArn": "arn:seaweed:iam::role/S3WriteRole",
+      "attachedPolicies": ["S3WritePolicy"],
+      "trustPolicy": {
+        "Version": "2012-10-17",
+        "Statement": [
+          {
+            "Effect": "Allow",
+            "Principal": { "Federated": "*" },
+            "Action": ["sts:AssumeRoleWithWebIdentity"],
+            "Condition": {
+              "StringEquals": { "seaweed:Issuer": "https://KEYCLOAK/realms/seaweedfs" }
+            }
+          }
+        ]
+      }
+    },
+    {
+      "roleName": "S3AdminRole",
+      "roleArn": "arn:seaweed:iam::role/S3AdminRole",
+      "attachedPolicies": ["S3AdminPolicy"],
+      "trustPolicy": {
+        "Version": "2012-10-17",
+        "Statement": [
+          {
+            "Effect": "Allow",
+            "Principal": { "Federated": "*" },
+            "Action": ["sts:AssumeRoleWithWebIdentity"],
+            "Condition": {
+              "StringEquals": { "seaweed:Issuer": "https://KEYCLOAK/realms/seaweedfs" }
+            }
+          }
+        ]
+      }
+    }
+  ]
+}
+```
+
+Notes:
+- Set `signingKey` to a strong random secret (base64-encoded 32+ bytes). All S3 gateway instances must share the same STS `issuer` and `signingKey`.
+- Explicit `jwksUri` and `userInfoUri` are recommended for Keycloak.
+- Ensure your Keycloak mappers populate a top-level `groups` (or `roles`) claim.
+
+## Step 3: Start the S3 Gateway
+
+```bash
+weed s3 -filer=filer:8888 -port=8333 -iam.config=/etc/seaweed/iam_keycloak.json
+```
+
+For multi-instance deployments, use the same IAM config on each instance.
+
+## Using It
+
+- Direct OIDC to S3 (Bearer): obtain a Keycloak access or ID token for client `seaweedfs-s3` and call S3 with:
+
+```bash
+curl -H "Authorization: Bearer $KEYCLOAK_TOKEN" http://s3-gateway:8333/
+```
+
+- Role selection: SeaweedFS maps OIDC claims via `roleMapping`. With the example above, users in `admins` get `S3AdminRole`, `developers` get `S3WriteRole`, others default to `S3ReadOnlyRole`.
+
+## Troubleshooting
+
+- Invalid token: verify token `iss` equals the configured provider `issuer` and `aud` or `azp` equals the client ID.
+- JWKS errors: ensure `jwksUri` is reachable from the S3 gateway. For Keycloak, use the `.../protocol/openid-connect/certs` endpoint.
+- No roles applied: confirm Keycloak mapper emits `groups` (or `roles`) at top-level in the token, and adjust `roleMapping` rules accordingly.
+- Trust policy denied: ensure `seaweed:Issuer` in the trust policy matches your Keycloak realm issuer exactly.
diff --git a/_Sidebar.md b/_Sidebar.md
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--- a/_Sidebar.md
+++ b/_Sidebar.md
@@ -91,6 +91,7 @@
 ### AWS IAM
 * [[Amazon IAM API]]
 * [[AWS IAM CLI]]
+* [[Keycloak Integration]]
 
 ### Machine Learning
 * [[TensorFlow with SeaweedFS]]