fix(getting-started): increase ext4 size and verify artifacts

We increased the ext4 size from 400M to 500M in our devtool scripts,
but not in the getting started. Let's bump it to 1G to avoid issues like
this in the future.

In the longer term, we may look into simplifying the getting started
guide, but for now it's quicker to just fix the issue.

Fixes: #5349
Signed-off-by: Riccardo Mancini <[email protected]>

Author: Manciukic

docs/getting-started.md

@@ -115,23 +115,29 @@ latest_ubuntu_key=$(curl "http://spec.ccfc.min.s3.amazonaws.com/?prefix=firecrac
     | sort -V | tail -1)
 ubuntu_version=$(basename $latest_ubuntu_key .squashfs | grep -oE '[0-9]+\.[0-9]+')
 
-# Download a rootfs
+# Download a rootfs from Firecracker CI
 wget -O ubuntu-$ubuntu_version.squashfs.upstream "https://s3.amazonaws.com/spec.ccfc.min/$latest_ubuntu_key"
 
-# Create an ssh key for the rootfs
+# The rootfs in our CI doesn't contain SSH keys to connect to the VM
+# For the purpose of this demo, let's create one and patch it in the rootfs
 unsquashfs ubuntu-$ubuntu_version.squashfs.upstream
 ssh-keygen -f id_rsa -N ""
 cp -v id_rsa.pub squashfs-root/root/.ssh/authorized_keys
 mv -v id_rsa ./ubuntu-$ubuntu_version.id_rsa
 # create ext4 filesystem image
 sudo chown -R root:root squashfs-root
-truncate -s 400M ubuntu-$ubuntu_version.ext4
+truncate -s 1G ubuntu-$ubuntu_version.ext4
 sudo mkfs.ext4 -d squashfs-root -F ubuntu-$ubuntu_version.ext4
 
 # Verify everything was correctly set up and print versions
-echo "Kernel: $(ls vmlinux-* | tail -1)"
-echo "Rootfs: $(ls *.ext4 | tail -1)"
-echo "SSH Key: $(ls *.id_rsa | tail -1)"
+echo
+echo "The following files were downloaded and set up:"
+KERNEL=$(ls vmlinux-* | tail -1)
+[ -f $KERNEL ] && echo "Kernel: $KERNEL" || echo "ERROR: Kernel $KERNEL does not exist"
+ROOTFS=$(ls *.ext4 | tail -1)
+e2fsck -fn $ROOTFS &>/dev/null && echo "Rootfs: $ROOTFS" || echo "ERROR: $ROOTFS is not a valid ext4 fs"
+KEY_NAME=$(ls *.id_rsa | tail -1)
+[ -f $KEY_NAME ] && echo "SSH Key: $KEY_NAME" || echo "ERROR: Key $KEY_NAME does not exist"
 ```
 
 ### Getting a Firecracker Binary