[Pacemaker] [pacemaker][patch 3/4] Simple changes for "Pacemaker Explained", Chapter 6 CH_Constraints.xml
Dejan Muhamedagic
dejanmm at fastmail.fm
Fri May 6 08:37:05 EDT 2011
On Fri, May 06, 2011 at 12:29:43PM +0200, Dejan Muhamedagic wrote:
> On Fri, May 06, 2011 at 09:47:29AM +0200, Andrew Beekhof wrote:
> > On Thu, May 5, 2011 at 5:20 PM, Dejan Muhamedagic <dejanmm at fastmail.fm> wrote:
> > > On Thu, May 05, 2011 at 12:02:01PM +0200, Andrew Beekhof wrote:
> > >> On Thu, May 5, 2011 at 11:37 AM, Dejan Muhamedagic <dejanmm at fastmail.fm> wrote:
> > >> > On Thu, May 05, 2011 at 09:07:05AM +0200, Andrew Beekhof wrote:
> > >> >> On Wed, May 4, 2011 at 7:15 PM, Dejan Muhamedagic <dejanmm at fastmail.fm> wrote:
> > >> >> > Hi,
> > >> >> >
> > >> >> > On Wed, May 04, 2011 at 12:49:03PM +0200, Andrew Beekhof wrote:
> > >> >> >> Tick tock. I'm going to push this soon unless someone raises an objection RSN.
> > >> >> >>
> > >> >> >> On Fri, Apr 15, 2011 at 4:55 PM, Andrew Beekhof <andrew at beekhof.net> wrote:
> > >> >> >> > On Fri, Apr 15, 2011 at 3:00 PM, Lars Marowsky-Bree <lmb at novell.com> wrote:
> > >> >> >> >> On 2011-04-13T08:37:12, Andrew Beekhof <andrew at beekhof.net> wrote:
> > >> >> >> >>
> > >> >> >> >>> >> Before:
> > >> >> >> >>> >>
> > >> >> >> >>> >> <rsc_colocation id="coloc-set" score="INFINITY">
> > >> >> >> >>> >> <resource_set id="coloc-set-0">
> > >> >> >> >>> >> <resource_ref id="dummy2"/>
> > >> >> >> >>> >> <resource_ref id="dummy3"/>
> > >> >> >> >>> >> </resource_set>
> > >> >> >> >>> >> <resource_set id="coloc-set-1" sequential="false" role="Master">
> > >> >> >> >>> >> <resource_ref id="dummy0"/>
> > >> >> >> >>> >> <resource_ref id="dummy1"/>
> > >> >> >> >>> >> </resource_set>
> > >> >> >> >>> >> </rsc_colocation>
> > >> >> >> >>> >> <rsc_order id="order-set" score="INFINITY">
> > >> >> >> >>> >> <resource_set id="order-set-0" role="Master">
> > >> >> >> >>> >> <resource_ref id="dummy0"/>
> > >> >> >> >>> >> <resource_ref id="dummy1"/>
> > >> >> >> >>> >> </resource_set>
> > >> >> >> >>> >> <resource_set id="order-set-1" sequential="false">
> > >> >> >> >>> >> <resource_ref id="dummy2"/>
> > >> >> >> >>> >> <resource_ref id="dummy3"/>
> > >> >> >> >>> >> </resource_set>
> > >> >> >> >>> >> </rsc_order>
> > >> >> >> >>> >>
> > >> >> >> >>> >>
> > >> >> >> >>> >>
> > >> >> >> >>> >> After:
> > >> >> >> >>
> > >> >> >> >> So I am understanding this properly - we're getting rid of the
> > >> >> >> >> "sequential" attribute, yes?
> > >> >> >> >
> > >> >> >> > Absolutely.
> > >> >> >
> > >> >> > So, the internal-collocation replaces the sequential attribute?
> > >> >>
> > >> >> Yes.
> > >> >>
> > >> >> > What are the possible and/or meaningfull values for
> > >> >> > internal-collocation? It looks like that would be 0 or INFINITY
> > >> >> > only, which would translate to old sequential false and true,
> > >> >> > right?
> > >> >>
> > >> >> No.
> > >> >>
> > >> >> <choice>
> > >> >> <data type="integer"/>
> > >> >> <value>INFINITY</value>
> > >> >> <value>+INFINITY</value>
> > >> >> <value>-INFINITY</value>
> > >> >> </choice>
> > >> >
> > >> > I saw that, but wonder what makes sense in this context. What's
> > >> > the difference between values 0, INF, 50, -50, 100? Are all those
> > >> > necessary?
> > >>
> > >> Just as necessary as for colocation constraints not involving sets.
> > >> You're setting up the colocation score between elements of the set.
> > >
> > > OK.
> > >
> > >> >> > Looking at the schema, the ordering constraint lost score
> > >> >>
> > >> >> Score was being mapped to "kind" inside the PE anyway.
> > >> >>
> > >> >> > and is
> > >> >> > using only the kind attribute which can have one of:
> > >> >> >
> > >> >> > <value>None</value>
> > >> >> > <value>Optional</value>
> > >> >> > <value>Mandatory</value>
> > >> >> > <value>Serialize</value>
> > >> >> >
> > >> >> > But then, the "kind" attribute is optional. If missing, how's
> > >> >> > that different from value None?
> > >> >>
> > >> >> If its missing you get the default. Which IIRC is Mandatory not None.
> > >> >>
> > >> >> > What does Serialize mean? (in orders)
> > >> >>
> > >> >> Same as it did before, this is not new.
> > >> >>
> > >> >> > What does score-attribute-mangle mean? (in collocations)
> > >> >>
> > >> >> As above. Not new.
> > >> >
> > >> > Where are these two documented? Couldn't find anything in the
> > >> > docs.
> > >>
> > >> Looks to be just an alias for XML_RULE_ATTR_SCORE_ATTRIBUTE dating back to 2005.
> > >> So there is probably a reason I didn't document it.
> > >
> > > So, it's obsolete then? The crm shell actually never supported
> > > it :-| And I can't recall that I've ever seen it in a
> > > configuration.
> > >
> > >> Serialize is newer. Its like optional but for a set - no member will
> > >> start or stop at the same time as another.
> > >
> > > OK.
> > >
> > >> >> > I think that it'd be good to clarify the shell syntax before
> > >> >> > applying these changes.
> >
> > Actually I'm going to flip-flop here... there's really no need for this.
> > Until the shell understands the new syntax, it will just show xml right?
>
> Right. But in my experience trying things out in shell syntax
> sometimes reveals design shortcomings. That was so with the
> resource sets.
>
> Going back to the example you've shown earlier in this thread ...
>
> Before:
>
> collocation c inf: ( dummy0:Master dummy1:Master ) dummy2 dummy3
> order o Mandatory: dummy0:promote dummy1:promote ( dummy2 dummy3 )
>
> After(1):
>
> collocation_set c inf: 0:[dummy0:Master dummy1:Master] inf:[dummy2 dummy3]
> order_set o Mandatory: Mandatory:[dummy0:promote dummy1:promote] Optional:[dummy2 dummy3]
>
> After(2):
>
> collocation_set c inf: 0:[dummy0:Master dummy1:Master] dummy2 dummy3
> order_set o Mandatory: dummy0:promote dummy1:promote Optional:[dummy2 dummy3]
>
> The second version removes redundant specification, i.e. for the
> sets which have the same kind/score as the constraint.
>
> Would this kind of XML be possible:
> <rsc_colocation id="coloc-set" score="INFINITY">
> <colocation_set id="coloc-set-1" internal-colocation="0">
> <resource_ref id="dummy0" role="Master"/>
> <resource_ref id="dummy1" role="Master"/>
> </colocation_set>
> <resource_ref id="dummy2"/>
> <resource_ref id="dummy3"/>
> </rsc_colocation>
> <rsc_order id="order-set" kind="Mandatory">
> <resource_ref id="dummy0" action="promote"/>
> <resource_ref id="dummy1" action="promote"/>
> <ordering_set id="order-set-1" internal-ordering="Optional">
> <resource_ref id="dummy2"/>
> <resource_ref id="dummy3"/>
> </ordering_set>
> </rsc_order>
Attached the corresponding RNG schema. Also includes change of
internal-colocation to internal-score and
internal-ordering to internal-kind
ordering_set remained, though to me order_set sounds a bit
better.
Let me know what you think about it. Caveat: I'm an absolute RNG
beginner.
Thanks,
Dejan
> For instance, that way we won't have single resource sets which
> look silly.
>
> > Also, the changes wont be in a release until 1.1.7 and it will take a
> > while to enter common usage.
> > So I think you have time.
>
> OK.
>
> > > I'm going to try to do something today and tomorrow, but next
> > > week I'll be away. So, if you're in a hurry, go ahead with the
> > > changes.
> > >
> > > Just two more notes regarding the language:
> > >
> > > There's "colocation_set/internal-colocation" and
> > > "ordering_set/internal-ordering". They sound different. Should
> > > the order stuff be "order_set/internal-order"? I'm not partial
> > > to any and furthermore not a native speaker, so I'll leave that
> > > to you and others who are more intimate with english.
> >
> > As an engineer my grasp on english can be tenuous at times, but
> > "internal-order" feels wrong.
>
> How about internal-score for both? I mean, we already know what
> kind of constraint it is.
>
> > > Are we going to name the new stuff differently in shell? Such as
> > > collocation_set and order(ing)_set? Though I don't like these in
> > > particular, because they are going to be the only ones with '_'
> > > in its names,
> >
> > I was using '-', but then I noticed all the other tag names used '_'.
> > Then I remembered deciding at one point to use '_' for tag names
> > (partly because changing them is hard) and '-' for attributes.
> >
> > Having said that, the tokens used by the shell are not required to
> > match those in the xml.
> > Though it may require more work when translating between xml and shell syntax.
>
> Yes, I know that, and I was actually asking about the names in
> the shell because I cannot think of anything better than
> order_set or collocation_set.
>
> > Remember to check the validate-with field though - to see which
> > version of the syntax the cluster is currently using.
>
> Right.
>
> Thanks,
>
> Dejan
>
> > > but there seems to be no way around it. Any better
> > > suggestions?
> > >
> > > Thanks,
> > >
> > > Dejan
> > >
> > > _______________________________________________
> > > Pacemaker mailing list: Pacemaker at oss.clusterlabs.org
> > > http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> > >
> > > Project Home: http://www.clusterlabs.org
> > > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> > > Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
> > >
> >
> > _______________________________________________
> > Pacemaker mailing list: Pacemaker at oss.clusterlabs.org
> > http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> >
> > Project Home: http://www.clusterlabs.org
> > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> > Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
>
> _______________________________________________
> Pacemaker mailing list: Pacemaker at oss.clusterlabs.org
> http://oss.clusterlabs.org/mailman/listinfo/pacemaker
>
> Project Home: http://www.clusterlabs.org
> Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf
> Bugs: http://developerbugs.linux-foundation.org/enter_bug.cgi?product=Pacemaker
-------------- next part --------------
<?xml version="1.0" encoding="utf-8"?>
<grammar xmlns="http://relaxng.org/ns/structure/1.0"
datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
<start>
<ref name="element-constraints"/>
</start>
<define name="element-constraints">
<zeroOrMore>
<choice>
<ref name="element-location"/>
<ref name="element-colocation"/>
<ref name="element-order"/>
</choice>
</zeroOrMore>
</define>
<define name="element-location">
<element name="rsc_location">
<attribute name="id"><data type="ID"/></attribute>
<attribute name="rsc"><data type="IDREF"/></attribute>
<choice>
<group>
<optional>
<attribute name="role">
<ref name="attribute-roles"/>
</attribute>
</optional>
<choice>
<attribute name="domain"><data type="IDREF"/></attribute>
<group>
<attribute name="node"><text/></attribute>
<externalRef href="score.rng"/>
</group>
</choice>
</group>
<oneOrMore>
<externalRef href="rule.rng"/>
</oneOrMore>
</choice>
<optional>
<ref name="element-lifetime"/>
</optional>
</element>
</define>
<define name="element-colocation">
<element name="rsc_colocation">
<attribute name="id"><data type="ID"/></attribute>
<optional>
<choice>
<externalRef href="score.rng"/>
<attribute name="score-attribute"><text/></attribute>
<attribute name="score-attribute-mangle"><text/></attribute>
</choice>
</optional>
<optional>
<ref name="element-lifetime"/>
</optional>
<choice>
<oneOrMore>
<choice>
<element name="colocation_set">
<attribute name="id"><data type="ID"/></attribute>
<optional>
<attribute name="internal-score">
<choice>
<data type="integer"/>
<value>INFINITY</value>
<value>+INFINITY</value>
<value>-INFINITY</value>
</choice>
</attribute>
</optional>
<oneOrMore>
<ref name="element-colocation-resource_ref"/>
</oneOrMore>
</element>
<ref name="element-colocation-resource_ref"/>
</choice>
</oneOrMore>
<group>
<attribute name="rsc"><data type="IDREF"/></attribute>
<attribute name="with-rsc"><data type="IDREF"/></attribute>
<optional>
<attribute name="node-attribute"><text/></attribute>
</optional>
<optional>
<attribute name="rsc-role">
<ref name="attribute-roles"/>
</attribute>
</optional>
<optional>
<attribute name="with-rsc-role">
<ref name="attribute-roles"/>
</attribute>
</optional>
<optional>
<attribute name="rsc-instance"><data type="integer"/></attribute>
</optional>
<optional>
<attribute name="with-rsc-instance"><data type="integer"/></attribute>
</optional>
</group>
</choice>
</element>
</define>
<define name="element-order">
<element name="rsc_order">
<attribute name="id"><data type="ID"/></attribute>
<optional>
<ref name="element-lifetime"/>
</optional>
<optional>
<attribute name="symmetrical"><data type="boolean"/></attribute>
</optional>
<optional>
<choice>
<attribute name="kind">
<ref name="order-types"/>
</attribute>
</choice>
</optional>
<choice>
<oneOrMore>
<choice>
<element name="ordering_set">
<attribute name="id"><data type="ID"/></attribute>
<attribute name="internal-kind">
<ref name="order-types"/>
</attribute>
<oneOrMore>
<ref name="element-order-resource_ref"/>
</oneOrMore>
</element>
<ref name="element-order-resource_ref"/>
</choice>
</oneOrMore>
<group>
<attribute name="first"><data type="IDREF"/></attribute>
<attribute name="then"><data type="IDREF"/></attribute>
<optional>
<attribute name="first-action">
<ref name="attribute-actions"/>
</attribute>
</optional>
<optional>
<attribute name="then-action">
<ref name="attribute-actions"/>
</attribute>
</optional>
<optional>
<attribute name="first-instance"><data type="integer"/></attribute>
</optional>
<optional>
<attribute name="then-instance"><data type="integer"/></attribute>
</optional>
</group>
</choice>
</element>
</define>
<define name="element-colocation-resource_ref">
<element name="resource_ref">
<attribute name="id"><data type="IDREF"/></attribute>
<optional>
<attribute name="instance"><data type="integer"/></attribute>
</optional>
<optional>
<attribute name="role">
<ref name="attribute-roles"/>
</attribute>
</optional>
</element>
</define>
<define name="element-order-resource_ref">
<element name="resource_ref">
<attribute name="id"><data type="IDREF"/></attribute>
<optional>
<attribute name="instance"><data type="integer"/></attribute>
</optional>
<optional>
<attribute name="action">
<ref name="attribute-actions"/>
</attribute>
</optional>
</element>
</define>
<define name="attribute-actions">
<choice>
<value>start</value>
<value>promote</value>
<value>demote</value>
<value>stop</value>
</choice>
</define>
<define name="attribute-roles">
<choice>
<value>Stopped</value>
<value>Started</value>
<value>Master</value>
<value>Slave</value>
</choice>
</define>
<define name="order-types">
<choice>
<value>None</value>
<value>Optional</value>
<value>Mandatory</value>
<value>Serialize</value>
</choice>
</define>
<define name="element-lifetime">
<element name="lifetime">
<oneOrMore>
<externalRef href="rule.rng"/>
</oneOrMore>
</element>
</define>
</grammar>
<!-- vim:ts=8:sw=2:
-->
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