mounted file "is a directory"

[Globegitter]

I am just testing out buildkite running it in google kubernetes engine, following the docs and I am running into issues when wanting to mount in secrets as a file via kubernetes. This is my yaml:

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
 name: buildkite-agent
 namespace: ci
spec:
 replicas: 1
 template:
   metadata:
     labels:
       app: buildkite-agent
   spec:
     containers:
       - name: buildkite-agent
         image: buildkite/agent:3
         imagePullPolicy: Always
         securityContext:
           privileged: true
         env:
           - name: BUILDKITE_AGENT_TOKEN
             valueFrom: {secretKeyRef: {name: buildkite-agent, key: token}}
           - name: BUILDKITE_BUILD_PATH
             value: "/home/kubernetes/flexvolume/buildkite/builds"
         volumeMounts:
           - name: docker-binary
             mountPath: /usr/bin/docker
           - name: docker-socket
             mountPath: /var/run/docker.sock
           - name: ssh-keys
             mountPath: /root/.ssh/id_rsa
             subPath: id_rsa
           - name: ssh-keys
             mountPath: /root/.ssh/id_rsa.pub
             subPath: id_rsa.pub
           - name: secrets
             mountPath: /home/kubernetes/flexvolume/secrets
           - name: buildkite-path
             mountPath: /home/kubernetes/flexvolume/buildkite/builds
     volumes:
       - name: docker-binary
         hostPath: {path: /usr/bin/docker}
       - name: docker-socket
         hostPath: {path: /var/run/docker.sock}
       - name: buildkite-path
         hostPath: {path: /home/kubernetes/flexvolume/buildkite/builds}
       - name: ssh-keys
         secret:
           secretName: buildkite-agent-ssh
           defaultMode: 0400
       - name: secrets
         secret:
           secretName: buildkite-agent-secrets
           defaultMode: 0400

Then my pipeline.yml:

steps:
  - label: Build
    command: ls -lah /home/kubernetes/flexvolume/secrets && cat /home/kubernetes/flexvolume/secrets/secrets.libsonnet
    plugins:
      - docker#v3.0.1:
          image: "ecosiadev/bazel-circleci:latest"
          mount-buildkite-agent: false
          propagate-environment: true
          additional-groups: ['root']
          user: 'root'
          volumes:
            - "/home/kubernetes/flexvolume/secrets:/home/kubernetes/flexvolume/secrets"

I can see that the secrets file exists in the first ls but for the cat command I am getting the error cat: /home/kubernetes/flexvolume/secrets/secrets.libsonnet: Is a directory. I can see that the kubernetes pod has the secrets file and I can read it but I have no idea why it is turned into a directory through this volume mount. Could it be in any way related to #61?

[Globegitter]

I might not need this functionality to work in the long run as we can also provides secrets differently but I still would like to know what is going on and would like to be able to fix this.

[toolmantim]

Sorry you had problems getting this going, and the belated reply. Did you have any luck? It sounds like the best way to diagnose it would be to use a vanilla bash script to run the plain Docker commands via the agent, and see the results.

[Globegitter]

I worked around the issue for now by passing it in as a base64 encoded environment variable and then decoding and storing it into a file in the command. Not nice but it works for now. Otherwise I had to pause progress one our buildkite ci setup for now, but hope to resume soon again.

[ritvick]

This is still and issue
when I try to mount something with
volumes:

• "/sourcePath/fileName:/destinationPath/fileName"

And later if I use /destinationPath/fileName it says its a directory. It is not recognizing it as a file.

[pzeballos]

Sorry @ritvick for the delay. I did a quick look but couldn't reproduce it, are you still having issues? did you have the issue on kubernetes? Thanks!

[pzeballos]

Hey folks! We did some tests but couldn't reproduce the issue, so I'm closing this. Feel free to re-open this if not. Thanks!

[axsuul]

Hi I am still experiencing this issue. I have a file on Docker container of build agent and attempt to mount it as volume as so:

steps:
  - label: "Test"
    command: "cat /root/.ssh/id_rsa"
    plugins:
      - docker#v5.9.0:
        image: "busybox"
        network: "host"
        volumes:
          - "/root/.ssh/id_rsa:/root/.ssh/id_rsa"

Then will output an error that /root/.ssh/id_rsa is a directory

[toote]

I think I was finally able to reproduce this issue: it happens when the source of the volume does not exist. You can even reproduce it without the plugin by running the following:

$ docker run --rm -t -v $HOME/.ssh/doesnotexist:/root/.ssh/id_rsa busybox cat /root/.ssh/id_rsa
cat: read error: Is a directory

Apparently, if the folder for the source exists but not the file, docker will create it as a folder (I could see $HOME/.ssh/doesnotexist existing afterwards in the host machine) and share it as if nothing was wrong 🤦