Filesystem actions in containers fail with Too many levels of symbolic links
Article Number: 000020104
Environment
Docker container or Kubernetes Pod with a volume defined that is mounted on the host with autofs, typically backed by NFS
Situation
When attempting to perform a filesystem action inside a container with a volume located on an autofs directory, the error Too many levels of symbolic links
is thrown and the action fails.
bash: cd: /data: Too many levels of symbolic links
Cause
As the share that backs the autofs volume isn't mounted until the directory specified is accessed, it is typically not mounted when a container is run.
With the default Docker bind-mount propagation of rprivate
, containers do not receive mount changes for volumes from the host.
Resolution
Docker
Mount the volume in question with the flag slave
, rslave
, shared
, or rshared
to ensure that mount changes are propagated to the container. Example: docker run -d -v /path/to/autofs:/data:shared ubuntu
See the links at the bottom of this article for info on what each of these flags does
Kubernetes
Define mountPropagation for the volume in question as either HostToContainer
(same as Docker's rslave
) or Bidirectional
(same as Docker's rshared
):
kind: Pod
apiVersion: v1
metadata:
name: test-app
spec:
containers:
- name: test
image: busybox
volumeMounts:
- mountPath: "/data"
name: test-app-vol
mountPropagation: HostToContainer
volumes:
- name: test-app-vol
hostPath:
path: /data