Fix CloudInit Boot Times

installing dhclient fixes ~2m startup time.

configs/bootstrap/cloudinit.conf

@@ -8,6 +8,7 @@ EXCLUDE = ["3.12", "3.13", "3.14"]
 
 packages {
   cloud-init          = true
+  dhclient            = true  # offically supported, for now
   openssh-server-pam  = true
   e2fsprogs-extra     = true  # for resize2fs
 }

[Stefan Reimer]

While at it you might want to add a dhcp.config which sets the MTU properly as well. All AWS uses 9001, but with default dhclient config you end up with 1500.

I eg. use the config found on the Ubuntu20.04 minimal AMI. Or do we want to leave any fine tuning up to the users and or via overlays ?

[Jake Buchholz Göktürk]

@Quarky9 if the MTU should be set for any NIC in a given cloud, or other similar cloud-wide tweaks, we should set it up, by default, in the image.

Could you open an issue with information/docs about MTU=9001 for AWS and how Ubuntu handles it? I presume this is something we may also want to do when dhclient isn't being used (the udhcpc default)...

[Jake Buchholz Göktürk]

Just found this -- https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/network_mtu.html, which says "Jumbo frames should be used with caution for internet-bound traffic or any traffic that leaves a VPC."

Setting MTU to 9001 might not be the best idea to set for a general-purpose default. Not sure why Ubuntu decided it was okay.

[Stefan Reimer]

Using the 9001 for years for various projects and customers at scale. Never had issue. That being said in light of this warning lets keep it simple and leave it to users / overlays to deviate from any standard and most likely working default settings. ;-)