[Hawkular-dev] Openshift/k8s templates, tagged images vs IfNotPresent

[Pavol Loffay]

On Tue, May 30, 2017 at 8:19 PM, Matt Wringe <mwringe at redhat.com> wrote:

> ----- Original Message -----
> > From: "Pavol Loffay" <ploffay at redhat.com>
> > To: "Discussions around Hawkular development" <
> hawkular-dev at lists.jboss.org>, "tech-list" <tech-list at redhat.com>,
> > obsidian-team-list at redhat.com
> > Sent: Tuesday, 30 May, 2017 10:26:20 AM
> > Subject: [Hawkular-dev] Openshift/k8s templates,      tagged images vs
> IfNotPresent
> >
> > Hi,
> >
> > we are providing OpenShift and k8s templates for Jaeger project
> > https://github.com/jaegertracing .
> >
> > What is the "standard" in the industry when providing public templates?
> > Should we use tagged versions of images or depend on IfNotPresent
> strategy
> > (pull image when not present)?
> >
> > I would say that public templates should use tagged versions because it's
> > always tested against a specific version and therefore guaranteed that it
> > works as expected. This also seems to be the case templates provided by
> > fabric8 team. Another thing is that templates not using tagged versions
> > might get quickly outdated.
> >
> > IfNotPresent may lead to weird states when a template is not compatible
> with
> > pulled image. Plus it does not allow to simply update deployment when
> using
> > tagged templates.
> >
> > I'm just interested in what people think and use.
>
> If you are doing releases where you are not going to be doing backports, I
> would say just set it to a specific version and use the default
> 'IfNotPresent' policy.
>
> If you are doing releases where you are going to be backporting issues, I
> would say to set it to a version alias and use the 'Always' policy.
>
> Eg for versions in which you provide backports:
>
> If your release is 1.2.0, then you would have an image tagged as 1.2.0 and
> also one tagged as v1.2. Your template would be set to the default v1.2
> version (tip: have the version set as a template parameter and not
> hardcoded so that its easy to configure)
>
> Let's say you need to backport a fix and how you are at 1.2.1, so now you
> tag your image 1.2.1 and again with v1.2 (which will overwrite the v1.2
> version so that it always points to the latest 1.2.x release)
>
> If your template is using v1.2 as the image tag, you will just need to
> restart your pod for the new image to be fetched and the pod will be using
> the updated containers (deploymentconfigs may also help here to
> automatically redeloy when a new image is available).
>
> If your user doesn't not want to automatically bring in the backported
> image with fixes (say they have a requirement to test each new image in a
> staging environment before pushing to production) then they can set the
> template parameter to '1.2.0' or some other specific version which
> shouldn't change. This will also allow a user to rollback a release to
> 1.2.2 if they are having a problem with 1.2.3
>
>
Thanks for the response. We haven't thought about backports, just not yet.
I like setting the version as a template parameter it's a nice approach +1.

I maybe did not ask very specificly. My question shoud be: Would you use
not tagged images in public templates e.g.
https://github.com/jaegertracing/jaeger-openshift/pull/8#issuecomment-304826256?
We should guarantee that our templates work properly and that is only by
using tagged versions. If we don't use tag and IfNotPresent andministrator
has to do more steps to get a proper version or update.

I can see that you always suggesting using tagged images, which is the same
I think.

Regards,


> >
> > --
> >
> >
> > PAVOL LOFFAY
> >
> > Red Hat Česká republika
> >
> > Purkyňova 111 TPB-B 612 45 Brno
> >
> > M: +421948286055
> >
> > _______________________________________________
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> > hawkular-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/hawkular-dev
> >
>
>


-- 

PAVOL LOFFAY

Red Hat Česká republika <https://www.redhat.com/>

Purkyňova 111 TPB-B 612 45 Brno

M: +421948286055
<https://red.ht/sig>
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