Automatically expand the filesystem on mounted volumes when they have grown

[jandubois]

Description

This issue applies to the diffdisk when the basedisk is an ISO (Alpine), and to additional volumes provided via #1065

Is is possible to expand the max file size of the image on the host (see #356 (comment)), but the additional space does not become available until the partition and filesystem have been extended to include the additional space.

This should be implemented in 05-persistent-data-volume.sh (renamed to 04-... once #1065 is merged).

@chrisx8 Is this something you would like to work on?

[chrisx8]

I can look into this, but I'm not too familiar with Alpine. Assuming it's on ext4, we can just run e2fsck then resize2fs in the script.

Questions:

• How do we handle errors, in case e2fsck or resize2fs fails?
• We probably should warn users if e2fsck fails, as this suggests the filesystem is unhealthy. Should we add this, if so, where?

[jandubois]

I can look into this, but I'm not too familiar with Alpine. Assuming it's on ext4, we can just run e2fsck then resize2fs in the script.

Yes, it is always ext4. I just checked, and our alpine-lima image has e2fsck, but not resize2fs. I will add e2fsprogs-extra to our images. We need to check if this is installed in the other distros, or if we need to install those dependencies there as well (which would require re-arranging some code in the boot sequence).

Questions:

• How do we handle errors, in case e2fsck or resize2fs fails?

I think it will just be logged, and then we proceed without resizing the filesystem.

• We probably should warn users if e2fsck fails, as this suggests the filesystem is unhealthy. Should we add this, if so, where?

This happens during boot via cloud-init. So I think the only thing we'll have are cloud-init logs.

Not sure what else we can do? Some warning via /etc/profile that this happened? I would ignore this for now; it can be added in a later PR if we feel it is necessary.

[jandubois]

I will add e2fsprogs-extra to our images.

Done in lima-vm/alpine-lima#88 (pending review).

I'll create a new tag/release once approved/merged.

[jandubois]

Alpine image with resize2fs has been released, and the examples/alpine.yaml has been updated in #1106 to use it.

[chrisx8]

@jandubois Can we have the cloud-utils-growpart package in Alpine? I want to use growpart to expand the partition on the datadisk.

[chrisx8]

Also, seems like boot scripts (including 05-persistent-data-volume.sh) are only ran on first start (creating instance from template) and not ran on subsequent launches (of existing instances). Is this expected?

[jandubois]

Can we have the cloud-utils-growpart package in Alpine? I want to use growpart to expand the partition on the datadisk.

Sure, I'll add it.

Also, seems like boot scripts (including 05-persistent-data-volume.sh) are only ran on first start (creating instance from template) and not ran on subsequent launches (of existing instances). Is this expected?

No, this is not expected (and I'm sure not the case). #273 is making sure that every boot is treated like a "first boot" so even scripts only executed during the first boot should be executed every time.

[jandubois]

Can we have the cloud-utils-growpart package in Alpine?

Added in #1118

[chrisx8]

Also, seems like boot scripts (including 05-persistent-data-volume.sh) are only ran on first start (creating instance from template) and not ran on subsequent launches (of existing instances). Is this expected?

Please disregard. Seems like it's caused by me not using e2fsck properly, so it wouldn't work without interactive terminals (like when launched by cloud-init)

I got this implement and #1126 is ready for review!