Github Actions执行SSH报错：伪终端无法分配的原因与解决

我尝试通过Github Runner连接SSH，但一直出现报错：pseudo-terminal will not be allocated because stdin is not a terminal。已经配置好私钥与known_hosts，且服务器未运行Docker，以下是我的Github Actions工作流配置：

name: deploy
on:
  pull_request:
    branches:
      - master
  
  workflow_dispatch:
    inputs:
      environment:
        description: 'Dpeloy'
        type: string
        default: 'Deploy'
        required: true
jobs:
  deploy:
    name: Deploy
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@master
      
      - name: Install SSH Key
        uses: shimataro/ssh-key-action@v2
        with:
          key: ${{ secrets.SSH_PRIVATE_KEY }}
          known_hosts: 'just-a-placeholder-so-we-dont-get-errors'
          
      - name: Adding Known Hosts
        run: ssh-keyscan -H ${{ secrets.SSH_HOST }} >> ~/.ssh/known_hosts
  
  - name: Connect to server
    run: "ssh root@${{ secrets.SSH_HOST }}"
    
  - name: Test
    run: "cd /var/www/test"

报错原因 #

1. 伪终端分配冲突：Github Actions的运行环境是非交互式的，默认SSH会尝试为会话分配伪终端（PTY），但这里的stdin不是终端设备，因此触发该警告。
2. Workflow语法错误：Connect to server和Test步骤缩进错误，被当成了独立的jobs而非deploy任务下的步骤；而且单独执行ssh命令会连接后立即退出，后续Test步骤是在Runner本地执行，根本不会在远程服务器上运行。

解决方案 #

1. 给SSH命令加-T参数，明确禁用伪终端分配，消除警告。
2. 通过SSH一次性传递所有需要在远程执行的命令——因为每个run步骤都是独立的，无法维持持续的SSH会话。
3. 修正Workflow的缩进，确保所有步骤都归属deploy任务。

修正后的Workflow配置 #

name: deploy
on:
  pull_request:
    branches:
      - master
  
  workflow_dispatch:
    inputs:
      environment:
        description: 'Deploy'
        type: string
        default: 'Deploy'
        required: true
jobs:
  deploy:
    name: Deploy
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@master
      
      - name: Install SSH Key
        uses: shimataro/ssh-key-action@v2
        with:
          key: ${{ secrets.SSH_PRIVATE_KEY }}
          known_hosts: 'just-a-placeholder-so-we-dont-get-errors'
          
      - name: Adding Known Hosts
        run: ssh-keyscan -H ${{ secrets.SSH_HOST }} >> ~/.ssh/known_hosts
  
      - name: Connect to server and run commands
        run: |
          ssh -T root@${{ secrets.SSH_HOST }} << 'EOF'
            cd /var/www/test
            # 这里可以追加更多远程操作命令，比如拉取代码、重启服务等
          EOF

内容的提问来源于stack exchange，提问作者Dan Rais