Post #2454613
2026-02-12 12:17 UTC
Replies (2)
-
@david_chisnall@infosec.exchange 2026-02-12 12:42
@drwx@mastodon.acc.sunet.se A jail is always an isolated thing. Different jail managers make slightly different distinctions between thick and thin, but generally thick means you get a new CoW clone of something, thin means that they are not quite CoW, there is an immutable base that is mapped read-only underneath the jail. The immutable layer can be updated underneath.
-
@brendan@social.brendans-bits.com 2026-02-12 16:29
@drwx@mastodon.acc.sunet.se The way I think of 'thick' vs 'thin' is whether the jail has its own copy of root and how it is upgraded. A thick jail has a copy of the base system to itself. Any changes to the base system affect that jail only. You have to upgrade the base of each jail individually. A thin jail shares the base amongst multiple concurrent jails. Any changes to base affect all jails. You can upgrade the base of multiple jails simultaneously by upgrading the shared base.