[Pulp-list] Long upgrade times from 2.6 -> 2.8

Brian Bouterse bbouters at redhat.com
Fri Jul 1 15:50:04 UTC 2016


With 2.8 specifically there is a *lot* of work done by the migrations 
and the runtime should scale with the content size. In other words I 
don't think it's doing useless work, there is just a lot of it.

I just did a quick audit of the two major offending migrations and they 
are implemented sanely so I don't think there is a quick fix to improve 
the runtime.

I believe to get a shorter runtime we would have to parallelize the 
migrations.

Regarding things going wrong, we do assume that migrations should be 
re-entrant meaning that if for some reason something strange occurs it 
should always be safe to run pulp-manage-db and it will pick up where it 
left off. Just a behavioral FYI.

These migration with 2.8 should not be norm, so I don't expect this to 
be very common in the future until maybe a major release (3.0).

Given all ^, what do you think we should do?

-Brian

On 07/01/2016 11:23 AM, Eric Helms wrote:
> I think there are a couple of considerations.
>
>  1) The first issue is that a 6-18 hour upgrade window is not something
> users expect and we've not been warning them of such so they can plan an
> outage accordingly. Lengthy upgrades also have that tendency to make
> users feel something is wrong or increase the risk that something can go
> wrong in between.
>  2) The fundamental question of - is this a bug or does this make
> perfect sense and how it has to work?
>  3) Applying the upgrade on an existing 2.6 if it changed nothing of the
> environment could work, the tough part is having to distribute that
> backwards. Pulp would have to distribute it back to 2.6, and Katello
> would have to push out patches to our 2.4 release channel.
>
> Eric
>
> On Fri, Jul 1, 2016 at 11:14 AM, Brian Bouterse <bbouters at redhat.com
> <mailto:bbouters at redhat.com>> wrote:
>
>     I'm trying to understand if the pain point is related to downtime or
>     total runtime.
>
>     For instance, what if these migration could be run as a
>     pre-migration step, ahead of time while Pulp was still online? The
>     upgrade would still take just as long but you could use your (in
>     this case) 2.6 install normally while the migrations are applying.
>     Once they are done then the actual upgrade of the codebase could be
>     very short.
>
>     -Brian
>
>     On 07/01/2016 09:20 AM, Eric Helms wrote:
>
>
>
>         On Fri, Jul 1, 2016 at 8:52 AM, Ashby, Jason (IMS)
>         <AshbyJ at imsweb.com <mailto:AshbyJ at imsweb.com>
>         <mailto:AshbyJ at imsweb.com <mailto:AshbyJ at imsweb.com>>> wrote:
>
>             FWIW I just upgraded from 2.7 -> 2.8 and it was approx. 1-2 hr
>             upgrade to get through the migrations in pulp-manage-db.____
>
>             __ __
>
>             290 GB /var/lib/pulp____
>
>             16 GB MongoDB____
>
>             __ __
>
>             *From:*pulp-list-bounces at redhat.com
>         <mailto:pulp-list-bounces at redhat.com>
>             <mailto:pulp-list-bounces at redhat.com
>         <mailto:pulp-list-bounces at redhat.com>>
>             [mailto:pulp-list-bounces at redhat.com
>         <mailto:pulp-list-bounces at redhat.com>
>             <mailto:pulp-list-bounces at redhat.com
>         <mailto:pulp-list-bounces at redhat.com>>] *On Behalf Of *Michael
>         Hrivnak
>             *Sent:* Friday, July 01, 2016 8:31 AM
>             *To:* Eric Helms <ehelms at redhat.com
>         <mailto:ehelms at redhat.com> <mailto:ehelms at redhat.com
>         <mailto:ehelms at redhat.com>>>
>             *Cc:* pulp-list <pulp-list at redhat.com
>         <mailto:pulp-list at redhat.com> <mailto:pulp-list at redhat.com
>         <mailto:pulp-list at redhat.com>>>
>             *Subject:* Re: [Pulp-list] Long upgrade times from 2.6 ->
>         2.8____
>
>             __ __
>
>             Did you get any feedback on whether one particular migration
>         seemed
>             to be running for a lot of that time?
>
>
>         For the 1.5TB/100GB MongoDB scenario here is what I am able to glean
>         from user logs (which I can share privately with anyone debugging):
>
>         ~5 hours: Applying pulp_puppet.plugins.migrations version 4
>         ~10 hours: Applying pulp_rpm.plugins.migrations version 28
>
>         Use reports "lots of stating, unlinking, and linking of all the
>         symlinks
>         in /var/lib/pulb" if that helps.
>
>         Another user reports ~6 hours on 176G of data.
>
>         Eric
>
>
>             ____
>
>             __ __
>
>             Michael____
>
>             __ __
>
>             On Fri, Jul 1, 2016 at 7:23 AM, Eric Helms
>         <ehelms at redhat.com <mailto:ehelms at redhat.com>
>             <mailto:ehelms at redhat.com <mailto:ehelms at redhat.com>>>
>         wrote:____
>
>                 Howdy,____
>
>                 __ __
>
>                 We (Katello) have had users reporting incredibly long
>         upgrade
>                 times when upgrading from 2.6 to 2.8. This occurs during the
>                 pulp-manage-db step that is run as the beginning of our
>                 installers upgrade process. Based on the numbers below, does
>                 this make sense at all?____
>
>                 __ __
>
>                 Some numbers:____
>
>                 __ __
>
>                 18 hour upgrade____
>
>                 1.5 TB /var/lib/pulp____
>
>                 100GB MongoDB____
>
>                 __ __
>
>                 __ __
>
>                 Thanks,____
>
>                 Eric____
>
>
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>
>             __ __
>
>
>
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