jenkins 配置git，出现无法连接git仓库的情况

ERROR: Timeout after 10 minutes
ERROR: Error cloning remote repo origin
hudson.plugins.git.GitException: Command "git fetch --tags --progress git@github.com:ejenna/wsg.git +refs/heads/*:refs/remotes/origin/*" returned status code 143:
stdout: 
stderr: 
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandIn(CliGitAPIImpl.java:2016)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.launchCommandWithCredentials(CliGitAPIImpl.java:1735)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl.access$300(CliGitAPIImpl.java:72)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$1.execute(CliGitAPIImpl.java:420)
	at org.jenkinsci.plugins.gitclient.CliGitAPIImpl$2.execute(CliGitAPIImpl.java:629)
	at hudson.plugins.git.GitSCM.retrieveChanges(GitSCM.java:1146)
	at hudson.plugins.git.GitSCM.checkout(GitSCM.java:1186)
	at hudson.scm.SCM.checkout(SCM.java:504)
	at hudson.model.AbstractProject.checkout(AbstractProject.java:1208)
	at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:574)
	at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:86)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:499)
	at hudson.model.Run.execute(Run.java:1819)
	at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
	at hudson.model.ResourceController.execute(ResourceController.java:97)
	at hudson.model.Executor.run(Executor.java:429)
ERROR: Error cloning remote repo origin

主要是~/.ssh/known_hosts中不存在已经访问过的记录，对于新的git需要手动验证一次之后，才能记录在~/.ssh/known_hosts中，下次就可以直接访问了

验证方法：

1、jenkins先跑一次项目，当他失败之后，项目的目录已经创建成功，git初始化成功

2、进入项目目录，一般是....../.jenkins/workspace/项目名称/，然后执行 git pull

3、会出现提示：Are you sure you want to continue connecting (yes/no)? 输入 yes

4、之后就可以正常访问了，去查看~/.ssh/known_hosts，多了一个ssh