containers/bootc
1
0
Fork 0
mirror of https://github.com/containers/bootc.git synced 2026-02-05 15:45:53 +01:00
Code Issues Activity

Merge pull request #1191 from cgwalters/stateoverlay-discouragement

Browse Source 
docs/filesystem: Weaken stateoverlay wording and direct to alternatives
This commit is contained in:
Colin Walters
2025-03-13 13:17:05 -04:00
committed by GitHub
parent 554c621dd0 877c339bba
commit 57adb67bf0
1 changed files with 16 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
docs/src/filesystem.md
View File

@@ -225,12 +225,25 @@ More on prepare-root: <https://ostreedev.github.io/ostree/man/ostree-prepare-roo
This feature enables a writable overlay on top of `/opt` (or really, any
toplevel or subdirectory baked into the image that is normally read-only).
Changes persist across reboots but during updates, new files from the container
image override any locally modified version. All other files persist.
To enable this feature, simply instantiate the `ostree-state-overlay@.service`
The semantics here are somewhat nuanced:
- Changes persist across reboots by default
- During updates, new files from the container image override any locally modified version
A disadvantage of this approach is that there is no equivalent to this feature in the
Docker/podman ecosystem, and while its semantics can often trivially enable many applications that
install into `/opt`, it can still be prone to "state drift".
To enable this feature, instantiate the `ostree-state-overlay@.service`
unit template on the target path. For example, for `/opt`:
```
RUN systemctl enable ostree-state-overlay@opt.service
```
### Alternatives to state overlays
See the section on `/opt` in [Image building and configuration guidance](building/guidance.md).
Essentially, add a redirect such as a symbolic link from `/opt/someapp/logs` or other
directories that should be writable+persistent to `/var/someapp/logs` instead.