92 lines
3.2 KiB
Bash
Executable file
92 lines
3.2 KiB
Bash
Executable file
#!/bin/bash
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# This script downloads the latest Linux kernel and rootfs images from Firecracker CI, patches the rootfs with an SSH key, and creates an ext4 filesystem image.
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required_commands=(
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uname
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curl
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basename
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grep
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sort
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tail
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wget
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unsquashfs
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ssh-keygen
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sudo
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chown
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truncate
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mkfs.ext4
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e2fsck
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)
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missing_commands=()
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for cmd in "${required_commands[@]}"; do
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if ! command -v "$cmd" >/dev/null 2>&1; then
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missing_commands+=("$cmd")
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fi
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done
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if [ ${#missing_commands[@]} -ne 0 ]; then
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echo "ERROR: Missing required program(s): ${missing_commands[*]}" >&2
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echo "Install missing dependencies and rerun." >&2
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exit 1
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fi
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ARCH="$(uname -m)"
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release_url="https://github.com/firecracker-microvm/firecracker/releases"
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latest_version=$(basename "$(curl -fsSLI -o /dev/null -w "%{url_effective}" "${release_url}/latest")")
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CI_VERSION=${latest_version%.*}
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latest_kernel_key=$(curl "http://spec.ccfc.min.s3.amazonaws.com/?prefix=firecracker-ci/$CI_VERSION/$ARCH/vmlinux-&list-type=2" \
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| grep -oP "(?<=<Key>)(firecracker-ci/$CI_VERSION/$ARCH/vmlinux-[0-9]+\.[0-9]+\.[0-9]{1,3})(?=</Key>)" \
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| sort -V | tail -1)
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# Download a linux kernel binary
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wget "https://s3.amazonaws.com/spec.ccfc.min/${latest_kernel_key}"
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latest_ubuntu_key=$(curl "http://spec.ccfc.min.s3.amazonaws.com/?prefix=firecracker-ci/$CI_VERSION/$ARCH/ubuntu-&list-type=2" \
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| grep -oP "(?<=<Key>)(firecracker-ci/$CI_VERSION/$ARCH/ubuntu-[0-9]+\.[0-9]+\.squashfs)(?=</Key>)" \
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| sort -V | tail -1)
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ubuntu_version=$(basename "$latest_ubuntu_key" .squashfs | grep -oE '[0-9]+\.[0-9]+')
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# Download a rootfs from Firecracker CI
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wget -O "ubuntu-${ubuntu_version}.squashfs.upstream" "https://s3.amazonaws.com/spec.ccfc.min/$latest_ubuntu_key"
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# The rootfs in our CI doesn't contain SSH keys to connect to the VM
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# For the purpose of this demo, let's create one and patch it in the rootfs
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sudo unsquashfs -f "ubuntu-${ubuntu_version}.squashfs.upstream"
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ssh-keygen -f id_rsa -N ""
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sudo cp -v id_rsa.pub squashfs-root/root/.ssh/authorized_keys
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mv -v id_rsa "./ubuntu-${ubuntu_version}.id_rsa"
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# create ext4 filesystem image
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sudo chown -R root:root squashfs-root
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truncate -s 1G "ubuntu-${ubuntu_version}.ext4"
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sudo mkfs.ext4 -d squashfs-root -F "ubuntu-${ubuntu_version}.ext4"
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# Verify everything was correctly set up and print versions
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echo
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echo "The following files were downloaded and set up:"
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kernel_files=(./vmlinux-*)
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if [ -e "${kernel_files[0]}" ]; then
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last_kernel_index=$((${#kernel_files[@]} - 1))
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KERNEL="${kernel_files[$last_kernel_index]}"
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echo "Kernel: $KERNEL"
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else
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echo "ERROR: Kernel image does not exist"
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fi
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rootfs_files=(./*.ext4)
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if [ -e "${rootfs_files[0]}" ]; then
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last_rootfs_index=$((${#rootfs_files[@]} - 1))
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ROOTFS="${rootfs_files[$last_rootfs_index]}"
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e2fsck -fn "$ROOTFS" &>/dev/null && echo "Rootfs: $ROOTFS" || echo "ERROR: $ROOTFS is not a valid ext4 fs"
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else
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echo "ERROR: Rootfs image does not exist"
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fi
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key_files=(./*.id_rsa)
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if [ -e "${key_files[0]}" ]; then
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last_key_index=$((${#key_files[@]} - 1))
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KEY_NAME="${key_files[$last_key_index]}"
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echo "SSH Key: $KEY_NAME"
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else
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echo "ERROR: SSH key does not exist"
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fi
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