[Dovecot] How to upgrade a running Dovecot?

[Jerry Yeager]

>

Have you considered sending out a message to each user to the effect  
that on some day, darned-early a.m. the system will be offline for 30  
minutes for maintenance (no incoming email will be lost, etc., etc.).



> Message: 3
> Date: Thu, 4 Oct 2007 13:57:03 +0100
> From: Mike Brudenell <pmb1 at york.ac.uk>
> Subject: [Dovecot] How to upgrade a running Dovecot?
> To: Dovecot Mailing List <dovecot at dovecot.org>
> Message-ID: <06B4C604-41E3-4061-96B2-C7C719E21D49 at york.ac.uk>
> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>
> Greetings -
>
> Could someone confirm how to perform various upgrades on a live
> system running Dovecot please?
>
>
> Scenario 1:  Change to dovecot.conf
> ===================================
> If I make a change to dovecot.conf am I right in thinking I can
> simply send a HUP signal to the main dovecot process to get it to re-
> read the configuration file and act on its revised content?
>

Yes, this is correct.



>
> Scenario 2:  Altered SSL Certificates
> =====================================
> I need to replace our current certificates and have prepared new
> files containing the replacement certificate and private key.  Am I
> right in thinking that I can simply modify dovecot.conf to point at
> the new files and send a HUP signal to dovecot?  Specifically, will
> new connections use the revised certificates, and existing
> connections continue to work OK without interruption?
>
>


Ehh not really, the auth child processes can be killed and new ones  
started. See your next scenario question.


> Scenario 3:  Software Upgrade
> =============================
> I build a particular version of Dovecot into the tree /usr/local/
> dovecot-A.B.C and then have a symlink called "dovecot" pointing at
> the this directory.  To upgrade I can then build the new version
> into /usr/local/dovecot-X.Y.Z and test.
>
> To actually switch over the live service to the new X.Y.Z version do
> I need to:
>
>    a) Totally shut down the old A.B.C version of Dovecot, thereby
> breaking all
>       open connections for users?  or
>
>    b) Assuming I am using "shutdown_clients = no" can I just kill the
> master
>       "dovecot" process and then start up the new version?
>

See the preface, do the update when you typically have few folks  
using the system -- which gives you fewer complaints from users  
should things break on their end.

> Ideally I want existing connections to remain running, but new
> connections to start up using the new X.Y.Z version of Dovecot.
>
> The comment for "shutdown_clients" implies this, but also says:
>
>      "This however means that after master process has died, the  
> client
>      processes can't write to log files anymore."
>
> So if I understand this correctly then with "shutdown_clients = no"
> in force then the sequence and behaviour is this? ...
>
>      1.  Old version A.B.C of Dovecot running, clients can log
> through the
>          master "dovecot" process to the logfiles.
>
>      2.  Kill the old master "dovecot" process, start new X.Y.Z
> version up.
>
>      3.  New connections get served by version X.Y.Z.
>          Old connections DON'T get killed and can continue, BUT can
> no longer
>          write anything to the logfiles?
>
>
> With many thanks,
> Mike B-)
>
> -- 
> The Computing Service, University of York, Heslington, York Yo10  
> 5DD, UK
> Tel:+44-1904-433811  FAX:+44-1904-433740
>
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> address. *
>
>
>
>
>
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