[ 
https://issues.apache.org/jira/browse/WHIRR-693?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
 ]

Paul Baclace updated WHIRR-693:
-------------------------------

    Description: 
A cluster can be specified with "waves" by supporting an optional suffix on 
whirr.instance-templates property in order to provide *running* base-level 
services (like ZK or a master-master mysql) to another layer of services during 
the configuration phase. This enables storing cluster-wide information in 
zookeeper or doing db creation beforehand. 

An example of a two "wave" (avoiding "phase" which already has a meaning) 
cluster:

  whirr.instance-templates.0=1 zookeeper, 2 zookeeper, 4 noop

The .0 templates run like normal during "whirr launch-cluster" and then, during 
the same Whirr run, the .1 template is applied as a modification of the same 
cluster so that new host instances are not allocated:

  whirr.instance-templates.1=1 my-master, 2 my-gateway, 4 my-worker

In the second wave, instance provisioning is inhibited, the instance-templates 
must have the same number of commas and same sequence of leading numbers, and a 
role is only allowed to appear in one wave. 

Here is another example:

  whirr.instance-templates.0=1 mysql-master+zookeeper, 1 
mysql-master+zookeeper,4 noop
  whirr.instance-templates.1=1 hadoop-namenode+hadoop-jobtracker, 1 
hbase-master+hadoop-secondarynn,4 
hadoop-tasktracker+hadoop-datanode+hbase-regionserver

In the first wave, the two mysql-masters form a multi-master ensemble which 
keeps state information about the setup in the Whirr process (much like 
ZooKeeperCluster.getHosts(cluster) informs services/hbase of the quorum).

In the second wave, nodes are not allocated (BootstrapClusterAction.doAction() 
is inhibited if instances already exist), but all phases for 
LaunchClusterCommand, including beforeBootstrap() and afterBootstrap() 
callbacks, are executed.  If other whirr.cli.command.*Command are run, they 
would see a combined whirr.instance-templates that works like normal.

Obviously, there would be no reason to limit this to 2 waves, but I do not 
expect more than 10 waves to be useful, so the pattern could enable a suffix of 
"\.[0-9]". 

Instead of WHIRR-221 which aims to specify a single global order for service 
startup, the wave format has the advantage that it relies on the implicit 
synchronization barriers at phases already supported by Whirr, the phases still 
run actions within phases in parallel, and state generated by a wave is 
available to later waves.

Conceptually, this merely splits the whirr.instance-templates into waves of 
(bootstrap,install,configure,start). If no .[0-9] suffixes are present, then 
Whirr would behave just like normal.


  was:
A cluster can be specified with "waves" by supporting an optional suffix on 
whirr.instance-templates property in order to provide *running* base-level 
services (like ZK or a master-master mysql) to another layer of services during 
the configuration phase. This enables storing cluster-wide information in 
zookeeper or doing db creation beforehand. 

An example of a two "wave" (avoiding "phase" which already has a meaning) 
cluster:

  whirr.instance-templates.0=1 zookeeper, 2 zookeeper, 4 noop

The .0 templates run like normal during "whirr launch-cluster" and then, during 
the same Whirr run, the .1 template is applied as a modification of the same 
cluster so that new host instances are not allocated:

  whirr.instance-templates.1=1 my-master, 2 my-gateway, 4 my-worker

In the second wave, instance provisioning is inhibited, the instance-templates 
must have the same number of commas and same sequence of leading numbers, and a 
role is only allowed to appear in one wave. 

Here is another example:

  whirr.instance-templates.0=1 mysql-master+zookeeper, 1 
mysql-master+zookeeper,4 noop
  whirr.instance-templates.1=1 hadoop-namenode+hadoop-jobtracker, 1 
hbase-master+hadoop-secondarynn,4 
hadoop-tasktracker+hadoop-datanode+hbase-regionserver

In the first wave, the two mysql-masters form a multi-master ensemble which 
keeps state information about the setup in the Whirr process (much like 
ZooKeeperCluster.getHosts(cluster) informs services/hbase of the quorum).

In the second wave, nodes are not allocated (BootstrapClusterAction.doAction() 
is inhibited if instances already exist), but all phases for 
LaunchClusterCommand, including beforeBootstrap() and afterBootstrap() 
callbacks, are executed.  If other whirr.cli.command.*Command are run, they 
would see a combined whirr.instance-templates that works like normal.

Obviously, there would be no reason to limit this to 2 waves, but I do not 
expect more than 10 waves to be useful, so the pattern could enable a suffix of 
"\.[0-9]". 

Instead of WHIRR-221 which aims to specify a single global order for service 
startup, the wave format has the advantage that it relies on the implicit 
synchronization barriers at phases already supported by Whirr, and state 
generated by a wave is available to later waves.

Conceptually, this merely splits the whirr.instance-templates into waves of 
(bootstrap,install,configure,start). If no .[0-9] suffixes are present, then 
Whirr would behave just like normal.


    
> Control order of actions with waves of whirr.instance-templates
> ---------------------------------------------------------------
>
>                 Key: WHIRR-693
>                 URL: https://issues.apache.org/jira/browse/WHIRR-693
>             Project: Whirr
>          Issue Type: Bug
>          Components: core
>            Reporter: Paul Baclace
>            Priority: Critical
>
> A cluster can be specified with "waves" by supporting an optional suffix on 
> whirr.instance-templates property in order to provide *running* base-level 
> services (like ZK or a master-master mysql) to another layer of services 
> during the configuration phase. This enables storing cluster-wide information 
> in zookeeper or doing db creation beforehand. 
> An example of a two "wave" (avoiding "phase" which already has a meaning) 
> cluster:
>   whirr.instance-templates.0=1 zookeeper, 2 zookeeper, 4 noop
> The .0 templates run like normal during "whirr launch-cluster" and then, 
> during the same Whirr run, the .1 template is applied as a modification of 
> the same cluster so that new host instances are not allocated:
>   whirr.instance-templates.1=1 my-master, 2 my-gateway, 4 my-worker
> In the second wave, instance provisioning is inhibited, the 
> instance-templates must have the same number of commas and same sequence of 
> leading numbers, and a role is only allowed to appear in one wave. 
> Here is another example:
>   whirr.instance-templates.0=1 mysql-master+zookeeper, 1 
> mysql-master+zookeeper,4 noop
>   whirr.instance-templates.1=1 hadoop-namenode+hadoop-jobtracker, 1 
> hbase-master+hadoop-secondarynn,4 
> hadoop-tasktracker+hadoop-datanode+hbase-regionserver
> In the first wave, the two mysql-masters form a multi-master ensemble which 
> keeps state information about the setup in the Whirr process (much like 
> ZooKeeperCluster.getHosts(cluster) informs services/hbase of the quorum).
> In the second wave, nodes are not allocated 
> (BootstrapClusterAction.doAction() is inhibited if instances already exist), 
> but all phases for LaunchClusterCommand, including beforeBootstrap() and 
> afterBootstrap() callbacks, are executed.  If other 
> whirr.cli.command.*Command are run, they would see a combined 
> whirr.instance-templates that works like normal.
> Obviously, there would be no reason to limit this to 2 waves, but I do not 
> expect more than 10 waves to be useful, so the pattern could enable a suffix 
> of "\.[0-9]". 
> Instead of WHIRR-221 which aims to specify a single global order for service 
> startup, the wave format has the advantage that it relies on the implicit 
> synchronization barriers at phases already supported by Whirr, the phases 
> still run actions within phases in parallel, and state generated by a wave is 
> available to later waves.
> Conceptually, this merely splits the whirr.instance-templates into waves of 
> (bootstrap,install,configure,start). If no .[0-9] suffixes are present, then 
> Whirr would behave just like normal.

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