Firecracker Setup

client.sh

#!/bin/bash

# Configure machine size
curl --unix-socket /tmp/firecracker.sock -i \
    -X PUT 'http://localhost/machine-config' \
    -H 'Accept: application/json'           \
    -H 'Content-Type: application/json'     \
    -d '{ "vcpu_count": 4, "mem_size_mib": 16384}'

# configure kernel path at firecracker
curl --unix-socket /tmp/firecracker.sock -i \
    -X PUT 'http://localhost/boot-source'   \
    -H 'Accept: application/json'           \
    -H 'Content-Type: application/json'     \
    -d '{        "kernel_image_path": "./vmlinux-5.10.198", "boot_args": "console=ttyS0 reboot=k panic=1 pci=off"    }'

# configure root fs at firecracker
curl --unix-socket /tmp/firecracker.sock -i \
    -X PUT 'http://localhost/drives/rootfs' \
    -H 'Accept: application/json'           \
    -H 'Content-Type: application/json'     \
    -d '{        "drive_id": "rootfs",        "path_on_host": "./rootfs.ext4",        "is_root_device": true,        "is_read_only": false    }'


# Configure network
#sudo ip tuntap add tap0 mode tap
#sudo ip addr add 172.16.0.1/30 dev tap0
#sudo ip link set tap0 up
#echo 1 | sudo tee /proc/sys/net/ipv4/ip_forward

#curl --unix-socket /tmp/firecracker.sock -i \
#  -X PUT 'http://localhost/network-interfaces/eth0' \
#  -H 'Accept: application/json' \
#  -H 'Content-Type: application/json' \
#  -d '{
#      "iface_id": "eth0",
#      "guest_mac": "06:00:AC:10:00:02",
#      "host_dev_name": "tap0"
#    }'

# starting instance
curl --unix-socket /tmp/firecracker.sock -i \
    -X PUT 'http://localhost/actions'       \
    -H  'Accept: application/json'          \
    -H  'Content-Type: application/json'    \
    -d '{        "action_type": "InstanceStart"     }'    

creating_rootfs.sh

#!/bin/bash

dd if=/dev/zero of=rootfs.ext4 bs=1M count=500
mkfs.ext4 rootfs.ext4
mkdir -p /tmp/my-rootfs
sudo mount rootfs.ext4 /tmp/my-rootfs

docker run -it --rm -v /tmp/my-rootfs:/my-rootfs alpine

# inside the container session
apk add openrc
apk add util-linux
apk add openjdk11
apk add sudo

# change password for root
echo "root:root" | sudo chpasswd

# Set up a login terminal on the serial console (ttyS0):
ln -s agetty /etc/init.d/agetty.ttyS0
echo ttyS0 > /etc/securetty
rc-update add agetty.ttyS0 default

# Make sure special file systems are mounted on boot:
rc-update add devfs boot
rc-update add procfs boot
rc-update add sysfs boot

# Then, copy the newly configured system to the rootfs image:
for d in bin etc lib root sbin usr; do tar c "/$d" | tar x -C /my-rootfs; done

# The above command may trigger the following message:
# tar: Removing leading "/" from member names
# However, this is just a warning, so you should be able to
# proceed with the setup process.

for dir in dev proc run sys var; do mkdir /my-rootfs/${dir}; done

cat <<EOF > /my-rootfs/Main.java

import java.util.Random;

public class Main {
    public static void main(String[] args) {

	      Random random = new Random();
      	byte[] mem = new byte[2147483546]; // ~4 GB

        var i = 0;
        while (true) {
	          // don't let JVM optimise stuff
      	    mem[random.nextInt(mem.length -1)] = (byte)random.nextInt(127);

            System.out.printf(
                "[uid: %d pid: %d] count: %d\n",
                new com.sun.security.auth.module.UnixSystem().getUid(),
                ProcessHandle.current().pid(),
                i);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                // do nothing
            }
            i++;
        }
    }
}
EOF

# All done, exit docker shell.
exit

# umount 
sudo umount /tmp/my-rootfs

restore.sh

#!/bin/bash

# loading snapshot
time curl --unix-socket /tmp/firecracker.sock -i \
    -X PUT 'http://localhost/snapshot/load' \
    -H  'Accept: application/json' \
    -H  'Content-Type: application/json' \
    -d '{
            "snapshot_path": "./snapshot_file",
            "mem_backend": {
                "backend_path": "./mem_file",
                "backend_type": "File"
            },
            "enable_diff_snapshots": true,
            "resume_vm": true
    }'

setup.sh

#!/bin/bash

sudo setfacl -m u:${USER}:rw /dev/kvm

curl -L https://github.com/firecracker-microvm/firecracker/releases/download/v1.11.0/firecracker-v1.11.0-x86_64.tgz --output firecracker-v1.11.0-x86_64.tgz
tar zxvf firecracker-v1.11.0-x86_64.tgz
export PATH=$(pwd)/release-v1.11.0-x86_64:$PATH
ln -s ~/release-v1.11.0-x86_64/firecracker-v1.11.0-x86_64 ~/release-v1.11.0-x86_64/firecracker

# Download docker - needed to build the rootfs image
sudo dnf install -y docker
sudo service docker start
sudo usermod -a -G docker ec2-user
exit
# log back again

# Initiate firecracker listener
firecracker --api-sock /tmp/firecracker.sock

snapshot.sh

#!/bin/bash

curl --unix-socket /tmp/firecracker.sock -i \
    -X PATCH 'http://localhost/vm' \
    -H 'Accept: application/json' \
    -H 'Content-Type: application/json' \
    -d '{
            "state": "Paused"
       }'
       
 time curl --unix-socket /tmp/firecracker.sock -i \
      -X PUT 'http://localhost/snapshot/create' \
      -H 'Accept: application/json' \
      -H 'Content-Type: application/json' \
      -d '{
            "snapshot_type": "Full",
            "snapshot_path": "./snapshot_file",
            "mem_file_path": "./mem_file"
          }'