Kubernetes Volume mountpath

[Montassar Dridi]

I'm running multiple web pods for the same application and I have this folder in my application where clients can upload their files.

the folder is sitting in this directory  /usr/local/tomcat/webapps/ROOT/uploadfiles and I want it to be shared between all the web pods, 

in case the client login to a random session within a specific web POD 1 and upload some files there, can find them next time he logs in to another random session within another web POD N 

I'm using Google Cloud Platform container engine and Google persistent disk as persistent volume

my web application Dockerfile for my image and DEPLOYMENT YAML files looks something like this 

FROM tomcat:8-jre8

ADD ROOT.war /usr/local/tomcat/webapps/

CMD ["catalina.sh", "run"]

---------------------------------------

apiVersion: v1

kind: PersistentVolumeClaim

metadata:

  name: web-pv-claim

  labels:

    name: web-pod

    version: v1

spec:

  accessModes:

    - ReadWriteOnce

  resources:

    requests:

      storage: 10Gi

------------------

apiVersion: extensions/v1beta1

kind: Deployment

metadata:

  name: web-dp

  labels:

    name: web-pod

    version: v1

spec:

      containers:

      - image: gcr.io/projectid/demo:v1

        name: web-pod

        ports:

        - containerPort: 8080

        volumeMounts:

        - name: persistent-storage

          mountPath: /usr/local/tomcat/webapps

     ports:

        - containerPort: 8080

      volumes:

      - name: persistent-storage

        persistentVolumeClaim:

          claimName: web-pv-claim

I get this error 

HTTP Status 404 - /monta

type Status report

message /monta

description The requested resource is not available.

---

Apache Tomcat/8.0.41

it's the same war file, my application worked fine without volume but as soon as I mountpath: /usr/local/tomcat/webapps I get that error also when i mountpath to a different directory like for example /sample then /usr/local/tomcat/webapps and /sample will have the same exact folders and files !!! and when I upload a file I only see it in the /usr/local/tomcat/webapps/ROOT/uploadefiles inside a specific pod and not shared to the other pods

[Saad Ali]

When you mount your volume into a path that already the existing content of that folder will be hidden. So in this case the existing contents of your container at "/usr/local/tomcat/webapps/" gets replaced with the contents of your PV that you mount to "/usr/local/tomcat/webapps".

Mounting your volume data to a different path is the correct thing to do, but you need to realize that the shared path is not  "/usr/local/tomcat/webapps/" but is the path you mount to, e.g. "/sample". 

> when i mountpath to a different directory like for example /sample then /usr/local/tomcat/webapps and /sample will have the same exact folders and files

This is probably because you have identical content (a copy) in your container and on your PV.

> when I upload a file I only see it in the "/usr/local/tomcat/webapps/ROOT/uploadefiles" inside a specific pod and not shared to the other pods

Your application needs to be updated to write data to the shared folder PV folder (e.g. "/sample"). It appears that by default it uploads the contents to "/usr/local/tomcat/webapps/ROOT/uploadfiles" which (if your PV is mounted to "/sample") is local to the container (not shared).

If you can't change the folder that your application writes the uploaded files to. You can mount your PV directly to "/usr/local/tomcat/webapps/ROOT/uploadfiles" instead of "/usr/local/tomcat/webapps/", assuming that path contains no data initially.

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[Montassar Dridi]

If you can't change the folder that your application writes the uploaded files to. You can mount your PV directly to "/usr/local/tomcat/webapps/ROOT/uploadfiles" instead of "/usr/local/tomcat/webapps/", assuming that path contains no data initially.

I tried that and "/usr/local/tomcat/webapps/ROOT/uploadfiles"  has the same folders and files as "/usr/local/tomcat/webapps/  !!

same issue as the one discribed below:

> when i mountpath to a different directory like for example /sample then /usr/local/tomcat/webapps and /sample will have the same exact folders and files

This is probably because you have identical content (a copy) in your container and on your PV.

Can you explain this point more

or if you have time can we chat I'll share my screen so you get a better idea of the problem

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[Montassar Dridi]

I delete the persistent disk and created another one 

now the "/usr/local/tomcat/webapps/ROOT/uploadfiles" is empty and has only lost+found

[Montassar Dridi]

I followed this two link :

https://github.com/fabric8io/gitcontroller/blob/master/vendor/k8s.io/kubernetes/examples/javaweb-tomcat-sidecar/javaweb.yaml

http://svblog.francedev.com/post/tutorial-kubernetes-java-tomcat-cloudsql-part1/

that's why I got same files in /usr/local/tomcat/webapps/  and any other directory 

so i think the best solution is to edit my application and upload the files in a directory outside of /usr/local/tomcat/webapps/