#1453 clm: Call plug-in script when an unconfigured node tries to join the cluster

[Anders Widell]

Add support in CLM for calling a plug-in script when an unconfigured node tries to join the cluster. The use-case is primarily scale-out in cloud. By installing such a plug-in, it will be possible for an application to automatically add appropriate IMM configuration objects for a new node and let it join the cluster.

[Mathi Naickan]

Iam not sure i understood the scenario thoroughly. But, there are questions like

• This is an admin's job of setting up the IMM configuration. This should be done by an OpenSAF external tool/script. Why should CLM bother about what an admin would do?
  i.e. What is the problem that the external script cannot solve that we are thinking of making OpenSAF do the configuration on behalf of the admin?

[Anders Widell]

The idea is that the admin will provide the plug-in script that is called by OpenSAF to automatically expand the cluster. So CLM is not expected to reconfigure the system by itself; its only job here is to trigger the execution of the user-provided script when an unconfigured node tries to join.

[Anders Widell]

Here is a prototype patch for this feature. Some parts are still missing:

• Make the feature configurable
• Add "batching" support - i.e. if many nodes try to join at the same time then we should call the script with a list of nodes, instead of calling the script one time for each node.

[Mathi Naickan]

What about the AMF cluster hosted on these CLM nodes? Who configures it, i will be amused if it has to be done by AMF itself!? What about application configurations? AMF will do it? I think i still don't understand the problem!

[Anders Widell]

The plug-in should add all configuration needed for the new node, i.e. both CLM & AMF configuration. The use-case is scale-out in a cloud, and the problem we are trying to solve is how to automatically bring in a new (scaled out) node into the cluster.

[Anders Widell]

changeset: 6986:9c55c17b24c0
branch: opensaf-4.7.x
parent: 6984:99821ea1c0cc
user: Anders Widell <an...sson.com>
date: Mon Oct 12 10:14:32 2015 +0200
summary: clmd: Add support for scale-out by calling a custom script to configure new nodes [#1453]</an...sson.com>

changeset: 6987:60536d29c33f
branch: opensaf-4.7.x
user: Anders Widell <an...sson.com>
date: Mon Oct 12 10:14:36 2015 +0200
summary: clmna: Re-try joining the cluster when CLMD returns TRY_AGAIN [#1453]</an...sson.com>

changeset: 6988:a21318bec696
parent: 6985:f9f8e549f071
user: Anders Widell <an...sson.com>
date: Mon Oct 12 10:14:32 2015 +0200
summary: clmd: Add support for scale-out by calling a custom script to configure new nodes [#1453]</an...sson.com>

changeset: 6989:07bcccab7961
tag: tip
user: Anders Widell <an...csson.com>
date: Mon Oct 12 10:14:36 2015 +0200
summary: clmna: Re-try joining the cluster when CLMD returns TRY_AGAIN [#1453]</an...csson.com>

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