Azure: post-deployment updates

Here are some techniques to dynamically modify a running Azure application.
They all rely on using blob storage as source of modification and presume that
the application was originally written to use these changes:

1. New/changed Silverlight applications

You can store your Silverlight xaps in blob storage and reference them from
pages served by a web role. You can use either public blob storage and Shared
Access Signature to control access to these blobs.(See
Marx’ blog
). You will need to make sure cross-domain policies are set up so
that the application can access the the server, which will obviously not be the
blob server. You can store meta-data for the applications either in blob
meta-data storage or, particularly if you need to search over it in SQL

2. Customization of ASP.NET look-and-feel

You can store a variety of
ASP.NET artifacts (master pages, aspx
pages, graphics, etc.) in blob storage and reference it from pages you serve
from a web role. Furthermore, you can use an execution-context sensitive
retrieval of these references to modify the source of these references to change
the appearance per user (e.g. in a multi-tenant branded web site). See
previous blog
for details.

3. Dynamically loaded assemblies

You can store additional assemblies in blob, discover and load them at
run-time. With this approach you need to consider the permissions of the account
you are running under and whether you would want to unload/change the assemblies
while executing (you would need to load separate app domains for that). This
approach wasdescribed by Manu. I am attaching another
sample using this approach in a web role.

4. Separate mountable disk

This approach is useful if
you are creating a vm role larger than
the maximum upload size of 64Gb.
Create the initial vm on two or more
disks, create the vm role from the
main drive and upload the additional drives as mountable blobs. You will need to
mount them as read-only snapshots to allow multiple instances to mount the same
blob. Also, note that a single-disk vm
role when created in Azure has additional disk(s) so do not assume that your
additional disks will be mounted as D, E, etc.

Attached is my presentation and some samples showing these approaches.



Post deployment

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