facing an issue for docker volume where

Hello I am facing an issue for docker volume where I am using frappe-app using docker-compose. I have downloaded and installed hrms on both frontend and backend containers. I want a backup of this volume so that i can attach it.

docker volume ls
local     pwd_db-data
local     pwd_logs
local     pwd_redis-queue-data
local     pwd_sites
local     student-api_postgres_data

I created a tar file by using

docker run --rm \
  -v pwd_sites:/source \
  -v $(pwd):/backup \
  busybox \
  sh -c "ls -la /source && tar czvf /backup/sites_backup.tar.gz -C /source ."

stopped and removed containers restored the volume and extracted the backup by using

docker volume create pwd_sites 
docker run --rm \
  -v pwd_sites:/target \
  -v $(pwd):/backup \
  busybox \
  tar xzvf /backup/sites_backup.tar.gz -C /target

modified my pwd.yaml (docker compose manifest)

version: "3"
services:
  backend:
    image: frappe/erpnext:v15.61.0
    volumes:
      - pwd_sites:/home/frappe/frappe-bench/sites
  # ... (other services)
volumes:
  pwd_sites:
    external: true

I came up with an error which is

docker compose -p pwd up -d
WARN[0000] The "ERPNEXT_VERSION" variable is not set. Defaulting to a blank string. 
WARN[0000] The "ERPNEXT_VERSION" variable is not set. Defaulting to a blank string. 
WARN[0000] The "ERPNEXT_VERSION" variable is not set. Defaulting to a blank string

Problem Summary

Backed up your pwd_sites volume to a tar file correctly.
Restored the volume from that tar file correctly.
Modified your docker-compose file to use this restored volume.
Faced this warning when running docker compose -p pwd up -d:

WARN[0000] The "ERPNEXT_VERSION" variable is not set. Defaulting to a blank string.

Explanation of the Warning

Docker Compose is expecting a variable ERPNEXT_VERSION, likely because your pwd.yaml or an imported file refers to it like this:

image: frappe/erpnext:${ERPNEXT_VERSION}

But since it's not set in your environment, it defaults to an empty string — which is why you're seeing this warning.

Fix the Warning

Option 1: Set the Variable in a .env File

Create a file named .env in the same folder as your docker-compose file (e.g., pwd.yaml) and add:

ERPNEXT_VERSION=v15.61.0

Docker Compose will automatically load variables from .env.

Option 2: Set it in the shell before running

export ERPNEXT_VERSION=v15.61.0
docker compose -p pwd up -d

Validating Your Volume Restoration

After you docker volume create and tar xzvf into the volume, it's a good idea to check if the expected files are there:

docker run --rm -v pwd_sites:/target busybox ls -la /target

You should see your apps.txt, sites/common_site_config.json, and the HRMS app folder in /target/apps.

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Sarthak Varshney1y ago
Accepted answer
Problem Summary
1. Backed up your pwd_sites volume to a tar file correctly.
2. Restored the volume from that tar file correctly.
3. Modified your docker-compose file to use this restored volume.
4. Faced this warning when running docker compose -p pwd up -d:
```
WARN[0000] The "ERPNEXT_VERSION" variable is not set. Defaulting to a blank string.
```
```
Explanation of the Warning
```
Docker Compose is expecting a variable ERPNEXT_VERSION, likely because your pwd.yaml or an imported file refers to it like this:
```
image: frappe/erpnext:${ERPNEXT_VERSION}
```
But since it's not set in your environment, it defaults to an empty string — which is why you're seeing this warning.

Fix the Warning

Option 1: Set the Variable in a .env File

Create a file named .env in the same folder as your docker-compose file (e.g., pwd.yaml) and add:
```
ERPNEXT_VERSION=v15.61.0
```
Docker Compose will automatically load variables from .env.

Option 2: Set it in the shell before running
```
export ERPNEXT_VERSION=v15.61.0
docker compose -p pwd up -d
```
Validating Your Volume Restoration

After you docker volume create and tar xzvf into the volume, it's a good idea to check if the expected files are there:
```
docker run --rm -v pwd_sites:/target busybox ls -la /target
```
You should see your apps.txt, sites/common_site_config.json, and the HRMS app folder in /target/apps.
+1