rtyler
/
evergreen
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Clarify that FIXME 

Granted, that was cryptic.
This commit is contained in:
Baptiste Mathus 2018-10-16 12:30:15 +02:00
parent 3fbfe9848b
commit ebace8026d
1 changed files with 14 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
distribution/client/src/lib/update.ts
View File

@ -231,8 +231,20 @@ export default class Update {
/*
* 1) Taint current level
* 2) query and trigger a new update
* (failing UL has been marked tainted for the instance, so should be served the/a previous UL)
* FIXME: 'the/a previous UL' => current code will serve "a" UL. We actually want "the"
* (failing UL has been marked tainted for the instance, so *should* be served the previous UL)
*
* FIXME: the served UL when rolling back could (rarely, but still) be different from the actual previous one before failed upgrade.
* Example:
*
* * an instance is on UL50
* * for some reason, this UL is globally tainted after the fact
* * a new UL51 is pushed
* * the instance updates to UL51, but fails, so initiate a rollback
* * it will per-instance taint UL51, then asks for where to go
* * the server will tell the instance to go to UL49, not UL50. So technically, this could cause issues,
* especially with the data snapshoting system and the associated restore...
* For now, we've ignored this issue, and granted this should almost never actually happen given host fast updates are pushed.
* But it's algorithmically and generally still _possible_.
*/
revertToPreviousUpdateLevel() {
this.snapshotter.revertToLevelBefore(this.getCurrentLevel()); // TODO test this