chore(deploy): refine systemd and nixos service docs (#3096)

* fix(deploy): simplify systemd service startup

* docs(deploy): add nixos systemd service example

* docs(deploy): add nixos service guide

* chore(deps): update pulsar and pyroscope

* docs(deploy): refine nixos service guidance

* fix(deploy): use explicit rustfs server entrypoint

deploy/build/rustfs.service

@@ -16,17 +16,11 @@ Group=rustfs
 # working directory
 WorkingDirectory=/opt/rustfs
 
-# environment variable configuration and main program (Option 1: Directly specify arguments)
-# Credentials are loaded from /etc/default/rustfs below. Replace the sample values before deployment.
-ExecStart=/usr/local/bin/rustfs \
-    --address 0.0.0.0:9000 \
-    --volumes /data/rustfs/vol1,/data/rustfs/vol2 \
-    --console-enable
-
-# environment variable configuration (Option 2: Use environment variables)
-# rustfs example file see: `../config/rustfs.env`
+# Environment-driven startup.
+# rustfs reads address, volumes, console, credentials, and other runtime settings
+# from RUSTFS_* variables. See `../config/rustfs.env` for an example template.
 EnvironmentFile=/etc/default/rustfs
-ExecStart=/usr/local/bin/rustfs  $RUSTFS_VOLUMES
+ExecStart=/usr/local/bin/rustfs server
 
 # service log configuration
 LogsDirectory=rustfs
@@ -43,8 +37,10 @@ Restart=always
 RestartSec=10s
 
 # graceful exit configuration
-TimeoutStartSec=30s
-TimeoutStopSec=30s
+# Type=notify waits for READY=1, so startup timeout must cover RustFS initialization
+# plus runtime readiness checks on slower disks or cold starts.
+TimeoutStartSec=120s
+TimeoutStopSec=45s
 
 # security settings
 NoNewPrivileges=true