Azure DevOps Pipeline中Git SSH子模块克隆失败问题及解决

问题现象 #

主仓库可正常克隆，但无法克隆通过SSH URL添加的子模块（本地Fedora环境已配置SSH可正常操作），克隆失败提示：

Please make sure you have the correct access rights
and the repository exists.
fatal: clone of 'git@ssh.dev.azure.com:v3/<rest_of_link>' into submodule path '/home/vsts/work/1/s/Modules' failed
Failed to clone 'Modules' a second time, aborting

尝试的操作 #

生成RSA密钥对后，使用Azure DevOps的InstallSSHKey@0任务安装密钥：

- task: InstallSSHKey@0
  inputs:
    knownHostsEntry: '<entry>'
    sshPublicKey: '<public_key>'
    sshKeySecureFile: 'id_rsa'

该任务执行成功，输出如下：

/usr/bin/ssh-agent
SSH_AUTH_SOCK=/tmp/ssh-XXXXXXFGcDdd/agent.1614; export SSH_AUTH_SOCK;
SSH_AGENT_PID=1615; export SSH_AGENT_PID;
echo Agent pid 1615;
/usr/bin/ssh-add -L
The agent has no identities.
/usr/bin/ssh-add /home/vsts/work/_temp/id_rsa
Identity added: /home/vsts/work/_temp/id_rsa (jose@42we-desktop)
/usr/bin/ssh-add
Finishing: InstallSSHKey

但执行以下命令初始化子模块仍失败：

GIT_SSH_COMMAND="ssh -v" git submodule update --init --recursive

调试日志 #

通过ssh -v的调试信息可见，已成功认证到ssh.dev.azure.com，但执行git-upload-pack后失败：

debug1: Authentications that can continue: password,publickey
debug1: Next authentication method: publickey
debug1: Offering public key: <key> RSA SHA256 <key> agent
debug1: Server accepts key: <key> RSA SHA256 <key> agent
Authenticated to ssh.dev.azure.com ([20.125.155.0]:22) using "publickey".
debug1: channel 0: new [client-session]
debug1: Entering interactive session.
debug1: pledge: filesystem
debug1: Sending environment.
debug1: channel 0: setting env GIT_PROTOCOL = "version=2"
debug1: channel 0: setting env LANG = "C.UTF-8"
debug1: Sending command: git-upload-pack 'v3/name/project/repo'
remote: Public key authentication failed.
debug1: client_input_channel_req: channel 0 rtype exit-status reply 0
debug1: channel 0: free: client-session, nchannels 1
Transferred: sent 3592, received 2304 bytes, in 2.1 seconds
Bytes per second: sent 1725.1, received 1106.5
debug1: Exit status 2
fatal: Could not read from remote repository.

本地克隆时，git-upload-pack前的流程均正常，仅Pipeline中出现该问题。

解决方法 #

已解决：最终发现需将生成的SSH公钥添加到我的Azure DevOps账户中。起初误以为Azure机器间会自动完成认证，添加公钥后问题解决！

内容的提问来源于stack exchange，提问作者Jose Guilherme