General questions regarding Mender


I have last few questions regarding Mender.

  1. Do I have to make my root file system read only? I have read the advantages and Disadvantages of read only file system. I guess my question is does mender prefer having read only file system?
  2. On a fresh new image. Why do I have to perform a rootsfs update before I can begin using delta updates. Is there a way around this?

For delta updates, yes. But not for anything else.

This is essentially a design bug in the client, and the reason is quite technical. Basically it boils down to that when you start with a fresh image, the state of the system is that no artifact is installed. However, the state should be that the artifact corresponding to the fresh image is installed. This causes the client to have no base to which to start from, and therefore it cannot install delta artifacts on the very first update.

We do have it on our backlog to fix this, but the fix is unfortunately quite complex.

1 Like

Sorry, I have to ask this again. So I have to have read-only rootfs in-order to perform delta-updates.
Or will delta-updates work without a read-only rootfs?

Exactly. Binary patches will not be applicable if the “source” (rootfs) changes, and hence this requirement.