在配置github actions自动部署前端项目到服务器上时，登录服务器使用的是秘钥登录。

出现报错：

[general] GITHUB_WORKSPACE:  /home/runner/work/clogin-frontend/clogin-frontend
[SSH] Creating /home/runner/.ssh dir in  /home/runner/work/clogin-frontend/clogin-frontend
✅ [SSH] dir created.
[SSH] Creating /home/runner/.ssh/known_hosts file in  /home/runner/work/clogin-frontend/clogin-frontend
✅ [SSH] file created.
✅ Ssh key added to `.ssh` dir  /home/runner/.ssh/deploy_key
[Rsync] Starting Rsync Action: /home/runner/work/clogin-frontend/clogin-frontend/public/ to ***@***:/study/github_actions/
[Rsync] exluding folders 
⚠️ [Rsync] error:  rsync exited with code 255
⚠️ [Rsync] stderr:  Warning: Permanently added '***' (ECDSA) to the list of known hosts.
Load key "/home/runner/.ssh/deploy_key": invalid format
Permission denied, please try again.
Permission denied, please try again.
***@***: Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: unexplained error (code 255) at io.c(235) [sender=3.1.3]

⚠️ [Rsync] stdout:  
⚠️ [Rsync] cmd:  rsync /home/runner/work/clogin-frontend/clogin-frontend/public/ ***@***:/study/github_actions/ --rsh "ssh -p 22 -i /home/runner/.ssh/deploy_key -o StrictHostKeyChecking=no" --recursive --exclude= -rltgoDzvO
 1: 0xb02ec0 node::Abort() [/home/runner/runners/2.299.1/externals/node16/bin/node]
 2: 0xb76589  [/home/runner/runners/2.299.1/externals/node16/bin/node]
 3: 0xd4a18e  [/home/runner/runners/2.299.1/externals/node16/bin/node]
 4: 0xd4b5af v8::internal::Builtin_HandleApiCall(int, unsigned long*, v8::internal::Isolate*) [/home/runner/runners/2.299.1/externals/node16/bin/node]
 5: 0x15e7959  [/home/runner/runners/2.299.1/externals/node16/bin/node]

在开头把问题关键说一下：秘钥格式不对！

关于怎么配置服务器秘钥登录，可以看看这个：

1. 制作密钥对

首先在服务器上制作密钥对。首先用密码登录到你打算使用密钥登录的账户，然后执行以下命令：

[root@host ~]$ ssh-keygen  <== 建立密钥对
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): <== 按 Enter
Created directory '/root/.ssh'.
Enter passphrase (empty for no passphrase): <== 输入密钥锁码，或直接按 Enter 留空
Enter same passphrase again: <== 再输入一遍密钥锁码
Your identification has been saved in /root/.ssh/id_rsa. <== 私钥
Your public key has been saved in /root/.ssh/id_rsa.pub. <== 公钥
The key fingerprint is:
0f:d3:e7:1a:1c:bd:5c:03:f1:19:f1:22:df:9b:cc:08 root@host

密钥锁码在使用私钥时必须输入，这样就可以保护私钥不被盗用。当然，也可以留空，实现无密码登录。

现在，在 root 用户的家目录中生成了一个 .ssh 的隐藏目录，内含两个密钥文件。id_rsa 为私钥，id_rsa.pub 为公钥。

2. 在服务器上安装公钥

键入以下命令，在服务器上安装公钥：

[root@host ~]$ cd .ssh
[root@host .ssh]$ cat id_rsa.pub >> authorized_keys

如此便完成了公钥的安装。为了确保连接成功，请保证以下文件权限正确：

[root@host .ssh]$ chmod 600 authorized_keys
[root@host .ssh]$ chmod 700 ~/.ssh

3. 设置 SSH，打开密钥登录功能

编辑 /etc/ssh/sshd_config 文件，进行如下设置：

RSAAuthentication yes
PubkeyAuthentication yes

另外，请留意 root 用户能否通过 SSH 登录：

PermitRootLogin yes

最后，重启 SSH 服务：

[root@host .ssh]$ service sshd restart

但是，到这里有一个很重要的步骤：将私钥转换成pem格式：

ssh-keygen -p -f ~/.ssh/id_rsa -m pem

vim 打开id_rsa，看看开头是不是-----BEGIN RSA PRIVATE KEY-----

配置秘钥登录

将服务器上的id_rsa文件传到本机，打开文件，复制全选，再到 github 代码库的setting里面，配置secret下的actions，将刚刚复制的秘钥配置到secret中，让github帮我们保管。之后在actions配置文件中通过${{ secrets.自定义名称 }}来引入就可以。

总之是秘钥格式问题，需要转换一下。