How to fix ERROR: Volume myvolume declared as external, but could not be found in Docker

# Create a named volume
docker volume create myvolume

# Verify it was created
docker volume ls | grep myvolume

# Inspect the volume details
docker volume inspect myvolume

# Create with a specific driver
docker volume create --driver local myvolume

# Create with driver options (e.g., for NFS)
docker volume create --driver local \
  --opt type=nfs \
  --opt o=addr=192.168.1.100,rw \
  --opt device=:/path/to/share \
  nfs-volume

volumes:
  myvolume:
    external: true

volumes:
  myvolume:

volumes:
  myvolume:
    external: false

# List all volumes on your system
docker volume ls

# Check the exact name Docker Compose expects
docker-compose config | grep -A5 volumes:

volumes:
  myvolume:
    external: true
    name: myvolume  # Use the exact name, ignoring project prefix

services:
  database:
    image: postgres:15
    volumes:
      - db-data:/var/lib/postgresql/data

volumes:
  db-data:
    external: true
    name: shared_postgres_data  # Actual volume name on the system

docker volume create shared_postgres_data

# List all volumes
docker volume ls

# Filter by name pattern
docker volume ls --filter name=myvolume

# Check a specific volume exists
docker volume inspect myvolume

[
    {
        "CreatedAt": "2024-01-15T10:30:00Z",
        "Driver": "local",
        "Labels": {},
        "Mountpoint": "/var/lib/docker/volumes/myvolume/_data",
        "Name": "myvolume",
        "Options": {},
        "Scope": "local"
    }
]

# V1 (standalone docker-compose)
docker-compose --version

# V2 (plugin)
docker compose version

volumes:
  myvolume:
    external:
      name: actual-volume-name

volumes:
  myvolume:
    external: true
    name: actual-volume-name

# Update Docker Compose plugin
docker compose version

# On Linux, update with your package manager
sudo apt update && sudo apt install docker-compose-plugin

# Check if the volume still exists
docker volume ls | grep myvolume

# If it was deleted, create it again
docker volume create myvolume

# Use labels to protect important volumes
docker volume create --label=important=true myvolume

# When pruning, be careful
docker volume prune  # This will list volumes to be deleted first

# Never use -f flag without checking first
docker volume prune -f  # DANGEROUS - no confirmation!

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      - name: Create external volumes
        run: |
          docker volume create myvolume
          docker volume create postgres_data

      - name: Start services
        run: docker-compose up -d

test:
  script:
    - docker volume create myvolume
    - docker-compose up -d

# docker-compose.ci.yml (volumes managed by Compose)
volumes:
  myvolume:
    # No external flag - Compose creates it

# In CI
docker-compose -f docker-compose.yml -f docker-compose.ci.yml up -d