Mapping local directory to kubernetes

Question

I am using Docker desktop to run a application in kubernetes platform where i need location to store files how can i use my local directory(c:\app-data) to be pointed to application running in kubernetes.

Answer 1

I had a similar problem. Docker contains are usually meant to be throwaway/gateway containers normally, so people don't usually use them for storing files.

That being said, you have two options:

1. Add path and files to docker container, which will cause your docker container to be massive in size (NOT RECOMMENDED). Docker build will require substantial time and memory, as all the files will be copied. Here's an example of creating a local ubuntu container with docker. https://thenewstack.io/docker-basics-how-to-share-data-between-a-docker-container-and-host/

2. Host your files through another server/api, and fetch those files using simple requests in your app. I used this solution. The only caveat is you need to be able to host your files somehow. This is easy enough, but may require extra payment. https://www.techradar.com/best/file-hosting-and-sharing-services

Answer 2

You can't really do this. The right approach depends on what the data you're trying to store is.

If you're just trying to store data somewhere – perhaps it's the backing data for a MySQL StatefulSet – you can create a PersistentVolumeClaim like normal. Minikube includes a minimal volume provisioner so you should automatically get a PersistentVolume created; you don't need to do any special setup for this. But, the PersistentVolume will live within the minikube container/VM; if you completely delete the minikube setup, it could delete that data, and you won't be able to directly access the data from the host.

If you have a data set on the host that your container needs to access, there are a couple of ways to do it. Keep in mind that, in a "real" Kubernetes cluster, you won't be able to access your local filesystem at all. Creating a PersistentVolume as above and then running a pod to copy the data into it could be one approach; as @ParmandeepChaddha suggests in their answer, baking the data into the image is another reasonable approach (this can be very reasonable if the data is only a couple of megabytes).

If the data is the input or output data to your process, you can also consider restructuring your application so that it transfers that data over a protocol like HTTP. Set up a NodePort Service in front of your application, and use a tool like curl to HTTP POST the data into the service.

Finally, you could be considering a setup where all of the important data is local: you have some batch files on the local system, the job's purpose is to convert some local files to other local files, and it's just that the program is in minikube. (Or, similarly, you're trying to develop your application and the source files are on your local system.) In this case Kubernetes, as a distributed, clustered container system, isn't the right tool. Running the application directly on your system is the best approach; you can simulate this with a docker run -v bind mount, but this is inconvenient and can lead to permission and environment problems.

(In theory you can use a hostPath volume too, and minikube has some support to mount a host directory into the VM. In practice, the setup required to do this is as complex as the rest of your Kubernetes setup combined, and it won't be portable to any other Kubernetes installation. I wouldn't attempt this.)

Answer 3

You can mount your local directory to your kubernetes Pod using hostPath. Your path c:\app-data on your Windows host should be represented as either /C/app-data or /host_mnt/c/app-data, depending on your Docker Desktop version as suggested in this comment.

You may also want to take a look at this answer.