Install `docker compose` plugin on Google Container-Optimized OS

install-docker-compose.sh

#!/bin/bash

VERSION="2.32.2"

# Install Docker Compose plugin in `/var/lib/google` (writable and stateful folder) 
sudo curl -sSL https://github.com/docker/compose/releases/download/v$VERSION/docker-compose-linux-x86_64 -o /var/lib/google/docker-compose
sudo chmod o+x /var/lib/google/docker-compose

# Create symlink to install Docker Compose plugin
mkdir -p ~/.docker/cli-plugins
ln -sf /var/lib/google/docker-compose ~/.docker/cli-plugins/docker-compose

Credit: https://serverfault.com/a/1149540

The writable and executable mounts are:

• /var/lib/{google,docker,toolbox} (stateful)
• /var/lib/cloud (stateless, tmpfs, 2 MB)
• /mnt/disks (stateless, tmpfs, 256 KB)

/var/lib/{google,docker,toolbox} are the best options, and /var/lib/google is probably better than /var/lib/docker because we have to set o+x (I suppose /var/lib/docker lacks o+x for a reason).