How to fix failed to solve with frontend dockerfile.v0: failed to create LLB definition: file with no instructions in Docker

First, confirm your Dockerfile exists and contains actual instructions:

# Check file exists and show size
ls -la Dockerfile

# Display file contents
cat Dockerfile

You should see instructions like FROM, RUN, COPY, etc. If the file is empty or shows nothing, you need to add content.

Minimum valid Dockerfile:

FROM alpine:latest

A common cause is editing a Dockerfile but forgetting to save it. Check your text editor:

1. Look for unsaved file indicators (dot or asterisk in tab title)
2. Press Ctrl+S (Windows/Linux) or Cmd+S (Mac) to save
3. Re-run your Docker build command

In VS Code, check the bottom status bar - unsaved files show a dot next to the filename.

File encoding problems can make content invisible to Docker. Check and fix encoding:

# Check file encoding
file Dockerfile

Expected output: Dockerfile: ASCII text or Dockerfile: UTF-8 Unicode text

If you see UTF-16, UTF-32, or unusual encoding, convert it:

Using iconv:

iconv -f UTF-16 -t UTF-8 Dockerfile > Dockerfile.new
mv Dockerfile.new Dockerfile

In VS Code:
1. Click the encoding in the bottom status bar (e.g., "UTF-16 LE")
2. Select "Save with Encoding"
3. Choose "UTF-8"

Windows uses CRLF line endings while Linux uses LF. This can cause parsing issues:

# Check for Windows line endings
cat -A Dockerfile | head -5

If you see ^M at the end of lines, you have Windows line endings.

Fix with dos2unix:

dos2unix Dockerfile

Fix with sed:

sed -i 's/\r$//' Dockerfile

Fix in VS Code:
1. Click "CRLF" in the bottom status bar
2. Select "LF"
3. Save the file

Docker may be looking at a different file than you expect:

# List all Dockerfile variants in current directory
ls -la Dockerfile* dockerfile*

Common naming issues:
- Linux is case-sensitive: dockerfile and Dockerfile are different files
- Docker defaults to Dockerfile (capital D)
- Hidden files: .Dockerfile won't be found

Explicitly specify the Dockerfile:

docker build -f ./Dockerfile -t myimage .

For docker-compose, specify in your compose file:

services:
  app:
    build:
      context: .
      dockerfile: Dockerfile

On Linux and WSL2, file permissions can prevent Docker from reading the Dockerfile:

# Check permissions
ls -la Dockerfile

# Fix permissions if needed
chmod 644 Dockerfile

WSL2 specific: Files copied directly from Windows Explorer to Ubuntu may have blank permissions:

# Recreate the file in WSL
cat Dockerfile > Dockerfile.new
mv Dockerfile.new Dockerfile

Ensure Docker can find your Dockerfile in the build context:

# Build from current directory (Dockerfile must be here)
docker build -t myimage .

# Build with explicit context path
docker build -t myimage -f /path/to/Dockerfile /path/to/context

Check your current directory:

pwd
ls -la Dockerfile

Make sure you're in the directory containing your Dockerfile, or use the -f flag to specify its location.

If other solutions don't work, recreate the Dockerfile to eliminate any hidden issues:

# Backup existing file
mv Dockerfile Dockerfile.bak

# Create new file with known-good content
cat > Dockerfile << 'EOF'
FROM alpine:latest
CMD ["echo", "Hello World"]
EOF

# Test the build
docker build -t test .

If this works, gradually copy your original instructions back, testing after each addition to identify which line causes problems.