<div dir="ltr"><div><span style="font-size:12.8px">Hi Matt,</span></div><div><span style="font-size:12.8px"> thanks for response.</span></div><span style="font-size:12.8px"><div><span style="font-size:12.8px"><br></span></div>PetSets are meant for clustering of pods which have persistent storage. If this is not your use case, what exactly are you trying to do? There may be better ways to handle it.</span><br><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">I am trying to figure out how to monitor wildfly in the openshift. </span><span style="font-size:12.8px">If I am not mistaken all the metric ids contain the feed id, feed id (at least for wildfly is autogenerated if it's not provided in the xml config). If container/pod is killed and re-created its history is lost with the feed id. That's why I thought the Pet Sets with persistent ids can help.</span></div><div><span style="font-size:12.8px"><br></span></div><div><span style="font-size:12.8px">jk</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Oct 19, 2016 at 3:49 PM, Matt Wringe <span dir="ltr"><<a href="mailto:mwringe@redhat.com" target="_blank">mwringe@redhat.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">----- Original Message -----<br>
> From: "Jiri Kremser" <<a href="mailto:jkremser@redhat.com">jkremser@redhat.com</a>><br>
> To: "Discussions around Hawkular development" <<a href="mailto:hawkular-dev@lists.jboss.org">hawkular-dev@lists.jboss.org</a>><br>
> Sent: Thursday, 13 October, 2016 8:21:10 AM<br>
> Subject: [Hawkular-dev] OpenShift Pet vs Cattle metaphor<br>
><br>
> Hello,<br>
> today, I was on L&L about storage in OpenShift and I learn interesting thing.<br>
> I always thought, that everything needs to be immutable and stateless and<br>
> all the state needs to be handled by means of NFS persistent volumes.<br>
> Luckily, there is a feature in Kubernetess (since 1.3) that allows the PODs<br>
> to be treated as pets. It's called PetSet [1] and it assigns a unique ID<br>
> (and persistent DNS record) to a POD that runs in this "mode".<br>
<br>
</span>For OpenShift, we would have moved to using PetSets for our Cassandra pod, but its not a fully supported feature yet. In the next version we will be moving over to using it.<br>
<br>
It will make changing the cluster size for Cassandra nodes a lot easier once we can use this.<br>
<span class=""><br>
><br>
> Common use-case for PetSet is a set of pods with a relational DBs that uses<br>
> some kind of master-slave replication and slaves needs to know the master's<br>
> address. But it can be used for anything. We can use the hostname as the<br>
> feed id for instance.<br>
><br>
> I don't know how much this will be popular because it kind of defeats the<br>
> purpose of immutable infrastructure but it can save us some work with the<br>
> feed identity. And of course we need to support also the "normal" POD<br>
> scenario.<br>
<br>
</span>PetSets are meant for clustering of pods which have persistent storage. If this is not your use case, what exactly are you trying to do? There may be better ways to handle it.<br>
<br>
><br>
> [1]: <a href="http://kubernetes.io/docs/user-guide/petset/" rel="noreferrer" target="_blank">http://kubernetes.io/docs/<wbr>user-guide/petset/</a><br>
><br>
> jk<br>
><br>
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</blockquote></div><br></div>