Re: is dpkg install atomic?
On Tue, Oct 26, 2021 at 10:31:54AM -0700, Han wrote:
> Hi,
>
> This might be a dumb question: is dpkg installing (or updating) a package
> using a .deb file atomic in the event of power outage?
>
> By atomic, I meant either the new version of the application is fully
> installed, or not at all. Is this always guaranteed?
No. A package can be in a "half-installed" state.
unicorn:~$ dpkg -l | head -n3
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
See where it says "Half-inst" in the middle? If an "H" is shown in
that column, the package is half-installed.
Also, the post-install scripts that most packages use are shell scripts,
so you already know a priori that the script could be interrupted
partway through.
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