When transitioning from Ubuntu to macOS, two commonly used commands in virtualization and disk management need equivalents:

• genisoimage for creating ISO images with metadata
• qemu-img for converting disk image formats

The macOS equivalent for genisoimage is hdiutil, Apple's native disk image utility. Here's how to create a similar ISO:

hdiutil makehybrid \
  -o init.iso \
  -hfs -joliet -iso -default-volume-name cidata \
  user-data meta-data

Key parameters explanation:

• -o: Specifies output file
• -hfs -joliet -iso: Sets filesystem formats
• -default-volume-name: Equivalent to -volid

If you prefer a more Linux-like experience, install cdrtools via Homebrew:

brew install cdrtools

Then use mkisofs (which is what genisoimage typically aliases to):

mkisofs -output init.iso -volid cidata -joliet -rock user-data meta-data

For qemu-img functionality, you have several options:

Option 1: Using qemu installed via Homebrew

brew install qemu
qemu-img convert -O raw disk.img disk.img.raw

Option 2: Using hdiutil for native conversion

hdiutil convert disk.img -format UDRW -o disk.img.raw

Note that UDRW format is equivalent to raw format.

When working with large disk images:

• For hdiutil, add -shadow flag to enable incremental operations
• For qemu-img, use -p flag to show progress
• Consider using pv pipe viewer for better progress monitoring

Creating a cloud-init ISO with multiple files:

hdiutil makehybrid -o cloud-init.iso \
  -hfs -joliet -iso -default-volume-name cidata \
  -filemode 0644 -mode 0644 \
  user-data meta-data network-config

Converting a VMDK to raw format:

qemu-img convert -p -O raw virtualdisk.vmdk virtualdisk.raw

If you encounter permission problems with hdiutil:

hdiutil makehybrid -o init.iso \
  -hfs -joliet -iso -default-volume-name cidata \
  -uid 0 -gid 80 \
  user-data meta-data

For sparse image conversion with qemu-img:

qemu-img convert -O raw -S 0 disk.img disk.img.raw

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When transitioning between Linux (Ubuntu) and macOS development environments, you'll frequently encounter situations where equivalent toolchains are needed. Two particularly important utilities for virtualization and disk image manipulation are:

• genisoimage for creating ISO images
• qemu-img for disk image conversion

The native solution on macOS is hdiutil, Apple's disk image utility. However, for ISO creation that mimics genisoimage behavior, consider these options:

# Using hdiutil (native macOS)
hdiutil makehybrid -iso -joliet -o output.iso source_folder

# Using mkisofs (available via Homebrew)
brew install cdrtools
mkisofs -output init.iso -volid cidata -joliet -rock user-data meta-data

For qemu-img functionality on macOS, these options are available:

# Using qemu-img (via Homebrew)
brew install qemu
qemu-img convert -O raw disk.img disk.img.raw

# Using hdiutil for basic conversion
hdiutil convert disk.img -format UDRW -o disk.img.raw

Here's a complete workflow for creating cloud-init data and converting a QCOW2 image on macOS:

# Create cloud-init ISO
mkisofs -output cloud-init.iso -volid cidata -joliet -rock user-data meta-data

# Convert QCOW2 to raw format
qemu-img convert -f qcow2 -O raw ubuntu.qcow2 ubuntu.raw

When working with large disk images on macOS:

• qemu-img tends to be faster than hdiutil for format conversions
• For ISO creation, mkisofs offers more compatibility with Linux-generated images
• Consider using pv (pipe viewer) for monitoring progress with large files

If you encounter permission problems with Homebrew-installed tools:

# Fix qemu-img permissions
sudo chmod +x $(brew --prefix qemu)/bin/qemu-img

For mkisofs/joliet compatibility issues:

mkisofs -J -r -V "VOLUME_ID" -o output.iso source_dir