support for stateful re-exec of upstart, now available for testing

[Lennart Poettering]

On Mon, 03.09.12 01:13, Steve Langasek (steve.langasek at ubuntu.com) wrote:

> Hi all,
> 
> Thanks to some great work by James, there is now a test branch of upstart
> available that supports passing its state when re-execing - rather important
> when re-execing an init that does process supervising!
> 
> You can find the code here:
> 
>   https://code.launchpad.net/~upstart-devel/upstart/stateful-reexec
> 
> Once landed, this will enable important functionality such as applying
> security updates without rebooting, being able to run upstart in an
> initramfs and pass state to the rootfs, and so on.  In the meantime, feel
> free to try the branch out and provide feedback on any issues you find.
> 
> You will need libjson-c 0.10 or later (available in Ubuntu quantal and
> Debian sid) to build this branch.  I believe James is planning to set up a
> launchpad recipe build for the branch as well, which I'm sure he will post
> once it's available.

Why don't you just serialize into a file rather than into a PIPE with
another process on the other side? Sounds much easier to create a file
in /dev/shm (or suchlike), delete it immediately and serialize to that,
and then hand over that fd. (Which is what we do in systemd) 

Lennart

-- 
Lennart Poettering - Red Hat, Inc.