Explore rootless Copilot CLI installation for ARC/DinD runners

[lpcox]

Summary

The Copilot CLI install script (actions/setup/sh/install_copilot_cli.sh) unconditionally uses sudo to install to /usr/local/bin. This forces ARC/DinD operators to allow privilege escalation in their runner pods, which conflicts with Kubernetes PodSecurity policies that enforce allowPrivilegeEscalation: false.

The AWF install script (install_awf_binary.sh) already solves this with a --rootless flag that installs to ~/.local/bin and ~/.local/lib/ without sudo. The Copilot CLI install could adopt a similar pattern.

Current sudo usage in install_copilot_cli.sh

Line	Command	Purpose
44	sudo chown -R "$(id -u):$(id -g)" "$COPILOT_DIR"	Fix ownership of .copilot dir created by chroot
53	sudo find /tmp -maxdepth 1 -name 'awf-*-chroot-home' ...	Clean up stale chroot home dirs
455	sudo install -m 0755 "$wrapper_path" "${INSTALL_DIR}/copilot"	Install wrapper script to /usr/local/bin
547	sudo tar -xz -C "${INSTALL_DIR}" -f ...	Extract binary to /usr/local/bin
548	sudo chmod +x "${INSTALL_DIR}/copilot"	Make binary executable

Proposed approach

Follow the install_awf_binary.sh pattern:

1. Accept a --rootless flag
2. When rootless, set INSTALL_DIR="${HOME}/.local/bin" instead of /usr/local/bin
3. Replace sudo calls with a maybe_sudo wrapper that skips sudo in rootless mode
4. Append $INSTALL_DIR to $GITHUB_PATH so subsequent steps find the binary
5. The chown and find cleanup calls may not need sudo at all in rootless mode since the files would be owned by the runner user

Impact

This would allow ARC/DinD runners to enforce allowPrivilegeEscalation: false in their pod security context, removing the last known limitation for ARC/DinD deployments documented in the setup guide.

Related

• Update ARC/DinD guide: remove resolved MCP gateway Docker socket limitation #46042 — Update ARC/DinD guide to clarify this limitation
• The allowPrivilegeEscalation: false known limitation in docs/src/content/docs/guides/arc-dind-copilot-agent.md