GitLab运行程序无法写入文件

Question

如下所示，我尝试使用高山docker镜像将我的公钥写入与docker的执行者共享的GitLab运行程序的/root/.ssh/known_hosts中。

变量$HOST_FINGERPRINT已初始化，可以通过命令echo $HOST_FINGERPRINT进行验证，但是由于某种原因它不能输出到known_hosts文件。

有人有什么线索吗？

$ ls -al
total 32
drwxrwxrwx    2 root     root          4096 Jul 11 00:15 .
drwxrwxrwx    8 root     root          4096 Jul 11 00:15 ..
-rwxrwxrwx    1 root     root           121 Jul 11 00:15 Dockerfile
-rwxrwxrwx    1 root     root           183 Jul 11 00:15 known_hosts
$ echo $HOST_FINGERFRINT
xxxxxxxxx, xxxxxxx, ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBAG/dWuic73JmrfWPxJkKlW2xXFUJUGkoF2XnPZeVMUE+LF4VU9QXnukuTXFiKCZQGqrnK8UquqSRc3Z/MTBBdo=
$ echo $HOST_FINGERPRINT > known_hosts
$ echo $?
0
$ ls -l .
total 16
-rwxrwxrwx    1 root     root           121 Jul 11 00:15 Dockerfile
-rwxrwxrwx    1 root     root             1 Jul 11 00:15 known_hosts
$ echo $HOST_FINGERPRINT > known
$ echo $?
0
$ ls -l .
total 24
-rwxrwxrwx    1 root     root           121 Jul 11 00:15 Dockerfile
-rw-r--r--    1 root     root             1 Jul 11 00:15 known
-rwxrwxrwx    1 root     root             1 Jul 11 00:15 known_hosts