REFACTOR: Update telemetry deployment docs and README for new Docker flow (#7250)

* fix(telemetry): make server build reproducible with proper context and deps

* Update telemetry/server/go.mod: go version

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

* telemetry/server: optimize Dockerfile (organize cache deps, copy proto); run as non-root

* telemetry: update deployment docs for new Docker build context

* telemetry: clarify Docker build/run docs and improve Dockerfile caching

- DEPLOYMENT.md: specify docker build must run from repo root; provide full docker run example with flags/port mapping
- README.md: remove fragile 'cd ..'; keep instruction to run build from repo root
- Dockerfile: remove unnecessary pre-copy before 'go mod download' to improve cache utilization

---------

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

3 files changed, 65 insertions, 19 deletions

diff --git a/telemetry/DEPLOYMENT.md b/telemetry/DEPLOYMENT.md
index dec46bff0..a1dd54907 100644
--- a/telemetry/DEPLOYMENT.md
+++ b/telemetry/DEPLOYMENT.md
@@ -1,6 +1,6 @@
 # SeaweedFS Telemetry Server Deployment
 
-This document describes how to deploy the SeaweedFS telemetry server to a remote server using GitHub Actions.
+This document describes how to deploy the SeaweedFS telemetry server to a remote server using GitHub Actions, or via Docker.
 
 ## Prerequisites
 
@@ -162,6 +162,48 @@ To deploy updates, manually trigger deployment:
 4. Check "Deploy telemetry server to remote server"
 5. Click "Run workflow"
 
+## Docker Deployment
+
+You can build and run the telemetry server using Docker locally or on a remote host.
+
+### Build
+
+- Using Docker Compose (recommended):
+
+```bash
+docker compose -f telemetry/docker-compose.yml build telemetry-server
+```
+
+- Using docker build directly (from the repository root):
+
+```bash
+docker build -t seaweedfs-telemetry \
+  -f telemetry/server/Dockerfile \
+  .
+```
+
+### Run
+
+- With Docker Compose:
+
+```bash
+docker compose -f telemetry/docker-compose.yml up -d telemetry-server
+```
+
+- With docker run:
+
+```bash
+docker run -d --name telemetry-server \
+  -p 8080:8080 \
+  seaweedfs-telemetry
+```
+
+Notes:
+
+- The container runs as a non-root user by default.
+- The image listens on port `8080` inside the container. Map it with `-p <host_port>:8080`.
+- You can pass flags to the server by appending them after the image name, e.g. `docker run -d -p 8353:8080 seaweedfs-telemetry -port=8353 -dashboard=false`.
+
 ## Server Directory Structure
 
 After setup, the remote server will have:
@@ -199,12 +241,19 @@ sudo systemctl start telemetry.service
 
 ## Accessing the Service
 
-After deployment, the telemetry server will be available at:
+After deployment, the telemetry server will be available at (default ports shown; adjust if you override with `-port`):
+
+- Docker default: `8080`
+  - **Dashboard**: `http://your-server:8080`
+  - **API**: `http://your-server:8080/api/*`
+  - **Metrics**: `http://your-server:8080/metrics`
+  - **Health Check**: `http://your-server:8080/health`
 
-- **Dashboard**: `http://your-server:8353`
-- **API**: `http://your-server:8353/api/*`
-- **Metrics**: `http://your-server:8353/metrics`
-- **Health Check**: `http://your-server:8353/health`
+- Systemd example (if you configured a different port, e.g. `8353`):
+  - **Dashboard**: `http://your-server:8353`
+  - **API**: `http://your-server:8353/api/*`
+  - **Metrics**: `http://your-server:8353/metrics`
+  - **Health Check**: `http://your-server:8353/health`
 
 ## Optional: Prometheus and Grafana Integration
 
diff --git a/telemetry/README.md b/telemetry/README.md
index 8066a0f0d..f2d1f1ccf 100644
--- a/telemetry/README.md
+++ b/telemetry/README.md
@@ -75,11 +75,11 @@ message TelemetryData {
 ```bash
 # Clone and start the complete monitoring stack
 git clone https://github.com/seaweedfs/seaweedfs.git
-cd seaweedfs/telemetry
-docker-compose up -d
+cd seaweedfs
+docker compose -f telemetry/docker-compose.yml up -d
 
 # Or run the server directly
-cd server
+cd telemetry/server
 go run . -port=8080 -dashboard=true
 ```
 
@@ -183,7 +183,9 @@ GET /metrics
 version: '3.8'
 services:
   telemetry-server:
-    build: ./server
+    build:
+      context: ../
+      dockerfile: telemetry/server/Dockerfile
     ports:
       - "8080:8080"
     command: ["-port=8080", "-dashboard=true", "-cleanup=24h"]
@@ -208,18 +210,17 @@ services:
 
 ```bash
 # Deploy the stack
-docker-compose up -d
+docker compose -f telemetry/docker-compose.yml up -d
 
 # Scale telemetry server if needed
-docker-compose up -d --scale telemetry-server=3
+docker compose -f telemetry/docker-compose.yml up -d --scale telemetry-server=3
 ```
 
 ### Server Only
 
 ```bash
-# Build and run telemetry server
-cd server
-docker build -t seaweedfs-telemetry .
+# Build and run telemetry server (build from repo root to include all sources)
+docker build -t seaweedfs-telemetry -f telemetry/server/Dockerfile .
 docker run -p 8080:8080 seaweedfs-telemetry -port=8080 -dashboard=true
 ```
 
diff --git a/telemetry/server/Dockerfile b/telemetry/server/Dockerfile
index 27fc3e86d..76fcb54cc 100644
--- a/telemetry/server/Dockerfile
+++ b/telemetry/server/Dockerfile
@@ -3,10 +3,6 @@ FROM golang:1.25-alpine AS builder
 WORKDIR /app
 
 COPY go.mod go.sum ./
-COPY telemetry/server/go.mod telemetry/server/go.sum ./telemetry/server/
-COPY telemetry/proto/ ./telemetry/proto/
-
-WORKDIR /app/telemetry/server
 RUN go mod download
 
 WORKDIR /app