[#596] feat(doc): Add doc for Hadoop access (#602)

### What changes were proposed in this pull request?
 - add `How to access Hadoop`
 - add runtime environment set up doc
 - Revised some content

### Why are the changes needed?
The workaround of cannot specify the Hadoop username

### Does this PR introduce _any_ user-facing change?
no

### How was this patch tested?
local test

conf/gravitino-env.sh.template

@@ -10,4 +10,4 @@
 # export GRAVITINO_HOME
 # export GRAVITINO_CONF_DIR
 # export GRAVITINO_LOG_DIR     # Where log files are stored.  PWD by default.
-# export GRAVITINO_MEM         # Gravitino jvm mem options Default -Xms1024m -Xmx1024m -XX:MaxMetaspaceSize=512m
+# export GRAVITINO_MEM         # Gravitino jvm mem options Default -Xms1024m -Xmx1024m -XX:MaxMetaspaceSize=512m

docs/gravitino-server-config.md

@@ -47,3 +47,15 @@ The following table lists the configuration items in the `gravitino.conf` file.
 |-----------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------|---------------|
 | `gravitino.catalog.cache.evictionIntervalMs`  | The interval in milliseconds to evict the catalog cache, default 3600000ms(1h)                                                                                                                          | `3600000`     | 0.1.0         |
 | `gravitino.catalog.classloader.isolated`      | Whether to use an isolated classloader for catalog, if it's true, all catalog-related libraries and configurations will be loaded by an isolated classloader NOT by AppClassLoader. Default value is `true` | `true`        | 0.1.0         |
+
+## How to set up runtime environment variables
+
+Gravitino server also supports setting up runtime environment variables by editing the `gravitino-env.sh` file, which is located in the `conf` directory.
+
+### How to access Hadoop
+
+Currently, due to the absence of a comprehensive user permission system, Gravitino can only use a single username for
+Hadoop access. Please ensure that the user starting the Gravitino server has Hadoop (HDFS, YARN, etc.) access
+permissions; otherwise, you may encounter a `Permission denied` error. There are also several ways to resolve this error:
+* Granting the Gravitino startup user permissions in Hadoop
+* Specify the authorized Hadoop username in the environment variables `HADOOP_USER_NAME` before starting the Gravitino server.

docs/iceberg-rest-service.md

@@ -1,5 +1,5 @@
 ---
-title: "How to setup Gravitino Iceberg REST server"
+title: "How to set up Gravitino Iceberg REST server"
 date: 2023-10-18T09:03:20-08:00
 license: "Copyright 2023 Datastrato.
 This software is licensed under the Apache License version 2."
@@ -12,6 +12,8 @@ Gravitino Iceberg REST Server follows the [Iceberg REST API specification](https
 * Support Iceberg REST API defined in Iceberg 1.3.1, support all namespace&table interface. `Token`, `ReportMetrics` and `Config` interface are not supported yet.
 * Worked as a catalog proxy, supports HiveCatalog and JdbcCatalog for now.
 * Build with Iceberg `1.3.1`, which means the Iceberg table format version is `1` by default.
+* When writing to HDFS, the Gravitino Iceberg REST server can only operate as the specified HDFS user when startup and
+  does not yet support proxying to other HDFS users. see *How to access Hadoop* in document *How to customize Gravitino server configurations* gravitino-server-config for more details.
 
 ## How to start the Gravitino Iceberg REST server
 

docs/integration-test.md

@@ -95,7 +95,7 @@ Before running the tests, make sure Docker is installed.
 Additionally, the Gravitino Server and third-party data source Docker runtime environments will use certain ports. Ensure that these ports are not already in use:
 
 - Gravitino Server: Port `8090`
-- Hive Docker runtime environment: Ports are `22`, `7180`, `8088`, `8888`, `9000`, `9083`, `10000`, `10002`, `50070`, and `50075`
+- Hive Docker runtime environment: Ports are `22`, `7180`, `8088`, `8888`, `9000`, `9083`, `10000`, `10002`, `50010`, `50070`, and `50075`
 
 ## Debugging Gravitino Server and Integration Tests
 
@@ -118,7 +118,7 @@ To debug the Gravitino Server and integration tests, you have two modes: `embedd
         - If you only debug integration test codes, You don't have to do any setup to debug directly
         - If you need to debug Gravitino server codes, follow these steps:
             - Enable the `GRAVITINO_DEBUG_OPTS` environment variable in the `distribution/package/conf/gravitino-env.sh` file to enable remote JVM debugging
-            - Manually start the Gravitino Server using the `./distribution/package/bin/gravitino-server.sh start` command
+            - Manually start the Gravitino Server using the `./distribution/package/bin/gravitino.sh start` command
             - Select `gravitino.server.main` module classpath in the `Remote JVM Debug` to attach the Gravitino Server process and debug it
 
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