Add or remove component dynamically for Slider Application

[Paul Han]

Hi, Slider Team

We are using Slider to deploy our multi-tenanted services to Yarn. For each
tenant, I add a new component to Slider cluster. The services are identical
except for the tenant it serve for, which is passed to the component as a
string parameter.

the appConfig file looks like something below:
{
  "global": {
    "tenantName": "TO_BE_OVER_WRITTEN_BY_COMPONENT",
  },
  "components": {
    "comp_a": {
      "tenantName": "tenant_a",
    },
    "comp_b": {
      "tenantName": "tenant_b",
    }
  }
}

metainfo.xml
...
   <components>

      <component>
        <name>comp_a</name>
        <category>MASTER</category>
        <compExports>Servers-host_port</compExports>
        <commandScript>
          <script>scripts/foo-service.py</script>
          <scriptType>PYTHON</scriptType>
        </commandScript>
      </component>

      <component>
        <name>comp_b</name>
        <category>MASTER</category>
        <compExports>Servers-host_port</compExports>
        <commandScript>
          <script>scripts/foo-service.py</script>
          <scriptType>PYTHON</scriptType>
        </commandScript>
      </component>

    </components>
...

I have two questions:
1. Is this the best I can do?
you can see that to deploy identical services(binary, command scripts are
all same) for multiple tenants, I need to modify metainfo.xml and
appConfig.json to have dup entries with just a param difference. Slider
cluster has to be destroy and recreated.

2. Once this is working, to add a new tenant to the cluster, I have to
modify the those files again and restart Slider cluster. The persistent
state such as app cache for services of existing tenants will be lost and
rebuilt again. That's very expensive operation for us. Is it possible to
add a component dynamically? Saw similar email threads about "Slider flex",
it doesn't do this, right?


Thanks,
Paul