Buildroot on qemu

buildroot_on_qemu.sh

curl -sOL https://buildroot.org/downloads/buildroot-2017.08.tar.gz
tar xf buildroot-2017.08.tar.gz
cd buildroot-2017.08/
make nconfig
# This is to point getty to the serial console instead of tty1
cat > /tmp/fixinittab.sh << 'EOF'
#!/bin/sh
sed -ie 's/tty1/ttyS0/g' ${TARGET_DIR}/etc/inittab
EOF
chmod +x /tmp/fixinittab.sh
# Configure your kernel to enable cgroups
make linux-nconfig
# > General Setup > Control Group Support (all sub options)
# Configure your system
make nconfig
# > Target package > System tools > docker-engine (all sub options)
# > Target package > System tools > cgroups-mount
make source
make
qemu-system-x86_64 \
  -kernel output/images/bzImage \
  -hda output/images/rootfs.ext2 \
  -m 128 \
  -boot c \
  -append "console=ttyS0 root=/dev/sda rw" \
  -no-reboot \
  -nographic \
  -net nic,model=virtio -net user \
  -redir tcp:2222::22
# If you have added the dropbear package, the last statement redirect
# your host 2222 port to the guest port 22 so you can connect by:
ssh root@localhost -p 2222
# Don't forget to set a password for root using the `passwd` command or else
# the ssh server will refuse the connection by default