我收到了权限被拒绝的错误，但不知道为什么。从我的jenkins主机上，我能够使用ssh-rsa密钥运行以下命令：
有任何想法为什么我会被拒绝访问？它试图做什么？
这是来自主jenkins的日志，点击[启动slave代理]按钮后：
scp /var/cache/jenkins/war/WEB-INF/slave.jar jenkins@<my_slave_host>:/var/jenkins/
注意：当我看到它不存在时，我手动在我的从机上创建了/var/jenkins/并将其归属于jenkins用户。我的主机jenkins配置为使用.jenkins@mySlaveHost使用ssh密钥。有任何想法为什么我会被拒绝访问？它试图做什么？
这是来自主jenkins的日志，点击[启动slave代理]按钮后：
[02/27/15 15:18:01] [SSH] Opening SSH connection to <my_slave_host>:22.
[02/27/15 15:18:02] [SSH] Authentication successful.
[02/27/15 15:18:03] [SSH] The remote users environment is:
BASH=/bin/bash
BASHOPTS=cmdhist:complete_fullquote:extquote:force_fignore:hostcomplete:interactive_comments:progcomp:promptvars:sourcepath
BASH_ALIASES=()
BASH_ARGC=()
BASH_ARGV=()
BASH_CMDS=()
BASH_EXECUTION_STRING=set
BASH_LINENO=()
BASH_SOURCE=()
BASH_VERSINFO=([0]="4" [1]="3" [2]="11" [3]="1" [4]="release" [5]="x86_64-pc-linux-gnu")
BASH_VERSION='4.3.11(1)-release'
CATALINA_HOME=/opt/tomcat/current
DIRSTACK=()
EUID=107
GROUPS=()
HOME=/var/lib/jenkins
HOSTNAME=*********** REMOVED***********
HOSTTYPE=x86_64
IFS=$' \t\n'
JAVA_HOME=/usr/lib/jvm/java-7-oracle
LANG=en_US.UTF-8
LOGNAME=jenkins
MACHTYPE=x86_64-pc-linux-gnu
MAIL=/var/mail/jenkins
OPTERR=1
OPTIND=1
OSTYPE=linux-gnu
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
PIPESTATUS=([0]="0")
PPID=10592
PS4='+ '
PWD=/var/lib/jenkins
SHELL=/bin/bash
SHELLOPTS=braceexpand:hashall:interactive-comments
SHLVL=1
SSH_CLIENT='10.57.13.32 34436 22'
SSH_CONNECTION='10.57.13.32 34436 10.57.6.42 22'
TERM=dumb
UID=107
USER=jenkins
XDG_RUNTIME_DIR=/run/user/107
XDG_SESSION_ID=42
_=']'
[02/27/15 15:18:03] [SSH] Checking java version of java
[02/27/15 15:18:04] [SSH] java -version returned 1.7.0_76.
[02/27/15 15:18:04] [SSH] Starting sftp client.
[02/27/15 15:18:04] [SSH] Copying latest slave.jar...
hudson.util.IOException2: Could not copy slave.jar into '/var/jenkins' on slave
at hudson.plugins.sshslaves.SSHLauncher.copySlaveJar(SSHLauncher.java:1019)
at hudson.plugins.sshslaves.SSHLauncher.access$300(SSHLauncher.java:133)
at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:709)
at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:696)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: hudson.util.IOException2: Could not copy slave.jar to '/var/jenkins/slave.jar' on slave
at hudson.plugins.sshslaves.SSHLauncher.copySlaveJar(SSHLauncher.java:1016)
... 7 more
Caused by: com.trilead.ssh2.SFTPException: Permission denied (SSH_FX_PERMISSION_DENIED: The user does not have sufficient permissions to perform the operation.)
at com.trilead.ssh2.SFTPv3Client.openFile(SFTPv3Client.java:1201)
at com.trilead.ssh2.SFTPv3Client.createFile(SFTPv3Client.java:1074)
at com.trilead.ssh2.SFTPv3Client.createFile(SFTPv3Client.java:1055)
at hudson.plugins.sshslaves.SFTPClient.writeToFile(SFTPClient.java:93)
at hudson.plugins.sshslaves.SSHLauncher.copySlaveJar(SSHLauncher.java:1008)
... 7 more
[02/27/15 15:18:04] Launch failed - cleaning up connection
[02/27/15 15:18:04] [SSH] Connection closed.
编辑： 这里是从属服务器上的 /var/jenkins：
$ ls -al
total 436
drwxr-xr-x 2 jenkins jenkins 22 Feb 27 15:17 .
drwxr-xr-x 14 root root 4096 Feb 27 15:12 ..
-rw-r--r-- 1 jenkins jenkins 439584 Feb 27 15:17 slave.jar
关于SFTP，我认为它未启用，你能指向任何说明文档表明SFTP是从属机的先决条件吗？我看到的所有页面都没有提到SFTP。
/var/jenkins的权限和所有权信息？例如，运行“ls -ld /var/jenkins”并将输出添加到问题中？如果该目录中存在slave.jar文件，请同时包括该文件的权限信息。 - Kenster