docs: fix Firecracker version and rootfs

During the last change we missed updating the Firecracker CI version.

Also keep the rootfs as ext4 for the rest of the guide.

Fixes: a69595f

Signed-off-by: Pablo Barbáchano <[email protected]>

Author: pb8o

docs/getting-started.md

@@ -100,21 +100,23 @@ kernel image with a Ubuntu 24.04 rootfs from our CI:
 ```bash
 ARCH="$(uname -m)"
 
-latest=$(wget "http://spec.ccfc.min.s3.amazonaws.com/?prefix=firecracker-ci/v1.10/$ARCH/vmlinux-5.10&list-type=2" -O - 2>/dev/null | grep -oP "(?<=<Key>)(firecracker-ci/v1.10/$ARCH/vmlinux-5\.10\.[0-9]{1,3})(?=</Key>)")
+latest=$(wget "http://spec.ccfc.min.s3.amazonaws.com/?prefix=firecracker-ci/v1.11/$ARCH/vmlinux-5.10&list-type=2" -O - 2>/dev/null | grep -oP "(?<=<Key>)(firecracker-ci/v1.11/$ARCH/vmlinux-5\.10\.[0-9]{1,3})(?=</Key>)")
 
 # Download a linux kernel binary
 wget "https://s3.amazonaws.com/spec.ccfc.min/${latest}"
 
 # Download a rootfs
-wget -O ubuntu-24.04.squashfs.upstream "https://s3.amazonaws.com/spec.ccfc.min/firecracker-ci/v1.10/${ARCH}/ubuntu-24.04.squashfs"
+wget -O ubuntu-24.04.squashfs.upstream "https://s3.amazonaws.com/spec.ccfc.min/firecracker-ci/v1.11/${ARCH}/ubuntu-24.04.squashfs"
 
 # Create an ssh key for the rootfs
 unsquashfs ubuntu-24.04.squashfs.upstream
 ssh-keygen -f id_rsa -N ""
 cp -v id_rsa.pub squashfs-root/root/.ssh/authorized_keys
 mv -v id_rsa ./ubuntu-24.04.id_rsa
-# re-squash
-mksquashfs squashfs-root ubuntu-24.04.squashfs -all-root -noappend -comp zstd
+# create ext4 filesystem image
+sudo chown -R root:root squashfs-root
+truncate -s 400M ubuntu-24.04.ext4
+sudo mkfs.ext4 -d squashfs-root -F ubuntu-24.04.ext4
 ```
 
 ### Getting a Firecracker Binary