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Contributor
Posts: 51
Registered: ‎10-02-2017

Configure device names for Azure instances during bootstrap

The AWS plugin for Cloudera Director supports the following directive to override the default device names during bootstrap.  Does the Azure plugin support something similar?  I do not see any online references indicating so, but hoping that I'm just not looking in the right place. 

 

ebsDeviceMappings {
deviceNamePrefix: /dev/sd
rangeStart: f
}

Cloudera Employee
Posts: 7
Registered: ‎01-14-2016

Re: Configure device names for Azure instances during bootstrap

Hi @dturner,

 

Overriding device name for Azure data disks is not supported by Cloudera Director Azure plugin.

 

Thanks,

Tony

Contributor
Posts: 51
Registered: ‎10-02-2017

Re: Configure device names for Azure instances during bootstrap

Thanks for your response Tony.

 

A couple of follow up questions:

 

1. Are there plans to add support for this in the plugin?  

 

2. Does this mean that it's not possible to use an image with a secondary disk device included, while still defining data drives in the Azure bootstrap?  In other words, Azure bootstrap assumes that the image contains only a single device, and that including any other device precludes the ability to use Cloudera Director to bootstrap that image with additional devices?

 

Cloudera Employee
Posts: 7
Registered: ‎01-14-2016

Re: Configure device names for Azure instances during bootstrap

There is no plan to support configurable block device name (for disks) in the Director Azure plugin. As you mentioned, using Azure custom VM image with pre-defined data disks requires no data disk to be specified.

 

Can you elaborate on the use case you have for using VM image with data disk(s)?

Contributor
Posts: 51
Registered: ‎10-02-2017

Re: Configure device names for Azure instances during bootstrap

For our AWS deployments, we include a secondary 500GB disk in the worker-core AMI which is used for Kafka data directory.  We include it in the image because you can only define volumes of 1 size per node type and we certainly do not want a 2TB volume for this Kafka disk - which is what we define for the data disks in the bootstrap file.  

Cloudera Employee
Posts: 7
Registered: ‎01-14-2016

Re: Configure device names for Azure instances during bootstrap

Thank you for sharing your use case details. In summary the use case is to support attaching heterogeneous (differen size) data disks for instances. As you noticed such configuration is not allowed in Director currently. We will relay your request to product management team.

 

Thanks,

Tony

Contributor
Posts: 51
Registered: ‎10-02-2017

Re: Configure device names for Azure instances during bootstrap

Thanks Tony. Preferably, yes - Director should support multiple disk sizes.

Just to clarify, the workaround we have in AWS is to use an image with an additional volume and then include a pre-bootstrap script that configures the device names / mounts to match the configs we define for each role. This works fine. I’m curious why the same approach couldn’t be used with Azure. Other than the difference in Linux device naming between AWS and Azure, I don’t see any other reason why this shouldn't be possible.

Anyway, thank you for forwarding the use case to your product team.
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