Change ccache directory to docker volume

[afbjorklund]

And apt install cmake to avoid host-cmake

• Mount the ccache directory in the docker image for ISO buildroot #22145

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Building cmake is the second longest build time (after the kernel)!

It even takes longer time than the compiler (gcc) and glibc packages.

[k8s-ci-robot]

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[Copilot]

Pull request overview

This PR aims to improve build performance for the minikube ISO by avoiding the lengthy process of building cmake from source and enabling persistent ccache storage via a Docker volume. The changes install cmake via apt (which is significantly faster than building from source) and configure a ccache directory that can be persisted across builds.

Key changes:

• Add cmake to the list of apt packages to avoid building it from source during the buildroot process
• Configure a custom ccache directory at /var/cache/buildroot/ccache and declare it as a Docker volume for potential persistence across builds

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[Copilot]

The VOLUME declaration will create an anonymous volume that won't persist between builds by default. To make the ccache persist and provide the performance benefits intended by this PR, the Makefile's docker run commands (lines 338 and 344) should mount a named volume or host directory to /var/cache/buildroot. Without this, each build will start with an empty ccache, negating the performance benefit. Consider either: 1) Adding an explicit volume mount in the Makefile's docker run commands, or 2) Documenting that users should set ISO_DOCKER_EXTRA_ARGS="-v minikube-buildroot-cache:/var/cache/buildroot" to benefit from ccache persistence.

[afbjorklund]

While true, this can come in a later PR

[afbjorklund]

I double-checked, and both variables will have the same end result. Not sure why it was failing before?

The problem was that it was prepending $HOME to the directory, so /tmp/var/cache/buildroot/ccache

Seems to be working now:

I have no name!@ff4e04d005f8:/mnt$ out/buildroot/output-x86_64/host/bin/ccache -sv
Cache directory:    /var/cache/buildroot/ccache
Config file:        /var/cache/buildroot/ccache/ccache.conf
System config file: /mnt/out/buildroot/output-x86_64/host/etc/ccache.conf

[k8s-ci-robot]

@afbjorklund: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
integration-vfkit-docker-macos-arm64	c704dc1	link	false	/test integration-vfkit-docker-macos-arm64
integration-docker-crio-linux-x86-64	c704dc1	link	true	/test integration-docker-crio-linux-x86-64
integration-kvm-docker-linux-x86-64	c704dc1	link	true	/test integration-kvm-docker-linux-x86-64
integration-kvm-crio-linux-x86-64	c704dc1	link	true	/test integration-kvm-crio-linux-x86-64
integration-kvm-docker-linux-x86	c704dc1	link	true	/test integration-kvm-docker-linux-x86
integration-docker-docker-linux-arm	c704dc1	link	true	/test integration-docker-docker-linux-arm
integration-kvm-crio-linux-x86	c704dc1	link	true	/test integration-kvm-crio-linux-x86
integration-docker-docker-linux-x86	c704dc1	link	true	/test integration-docker-docker-linux-x86
integration-docker-containerd-linux-x86	c704dc1	link	true	/test integration-docker-containerd-linux-x86
integration-docker-crio-linux-x86	c704dc1	link	true	/test integration-docker-crio-linux-x86
integration-kvm-containerd-linux-x86	c704dc1	link	true	/test integration-kvm-containerd-linux-x86
integration-none-docker-linux-x86	c704dc1	link	true	/test integration-none-docker-linux-x86

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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