Change CPUs, Memory and Disk
cubic modify changes the size of a VM instance after it was created.
Stop the VM Instance
CPUs, memory and disk apply when a VM instance starts, so stop it first:
$ cubic stop demo --wait
Change the Settings
$ cubic modify demo --cpus 2 --memory 2G --disk 200G
The command is quiet. Every flag is optional, so a single value can be changed on its own. Modifying a running VM instance works too and reminds you that the change needs a restart:
$ cubic modify demo --cpus 2
info: Note: changes may require a restart to take effect.
Check the Result
$ cubic show demo
Running: no
Arch: amd64
CPUs: 2
Memory: 2048 M
Disk Used: 448 M
Disk Total: 200 G
User: alice
Isolated: no
SSH Port: 33033
Monitor Port: 38283
Console Port: 42883
Start the VM instance again:
$ cubic start demo
The Disk Can Only Grow
The guest picks up a larger disk on the next boot, because the official images grow their root filesystem themselves:
$ cubic exec demo "df -h / | tail -1"
/dev/root 193G 724M 193G 1% /
Shrinking is refused, because it would cut into data that is already on the disk:
$ cubic modify demo --disk 10G
error: Cannot shrink the disk of the instance 'demo'