dotnet-az-snapshot-tool

Command line tool that creates Azure managed disk snapshots.

Main motivation was to be able to automate the creation of snapshots without using Runbooks and/or having to use Azure Backup with a Virtual Machine.

Installation

dotnet tool install --global dotnet-az-snapshot-tool

Usage

Available arguments:

--tenantId (-t): (Required) Azure Tenant ID of the user credentials used to create the snapshot.
--subscriptionId (-s): (Required) Azure subscription ID of the source disk for the snapshot.
--resourceGroup (-g): (Required) Resource group of the source disk for the snapshot.
--diskName (-n): (Required) Name of the source managed disk name.
--snapshotNameFormat (-f): Defines the name of the snapshot resource. Default is 'diskName-snapshot-yy-MM-dd.hh.mm.ss'.
--retainLimit (-l): Limits the retained snapshots to specified count. Default is unlimited (0).
--skuType (-k): Snapshot sku type. Available values are 'Standard_LRS' or 'Premium_LRS'. Default is 'Standard_LRS'..

Example

az-snapshot-tool create --tenantId xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx --subscriptionId xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx --resourceGroup myRg --diskName myDisk

az-snapshot-tool create -t xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx -s xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx -g myRg -n myDisk

To retain 7 latest snapshot values (including latest):

az-snapshot-tool create -t xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx -s xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx -g myRg -n myDisk --retainLimit 7

Details on authentication

This tool uses AzureDefaultCredentials which tries multiple credentials types in order, including environment variables, managed identity and az cli. See here for more details.

Using with a CronJob in Kubernetes

To easily automate the creation on snapshot in Kubernetes, use the CronJob resource. Here's an example using environment variables to provide the Azure Active Directory Application credentials. It retains the last 7 days of snapshots:

note: you can also use aad-pod-identity

apiVersion: batch/v1beta1
kind: CronJob
metadata:
  name: snapshot-job
spec:
  schedule: "@daily"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
          - name: snapshot
            image: mcr.microsoft.com/dotnet/core/sdk:3.1
            args:
            - /bin/sh
            - -c
            - >-
                dotnet tool install --tool-path . dotnet-az-snapshot-tool;
                ./az-snapshot-tool run
                -t xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
                -s xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx 
                -g myRg
                -n myDisk
                -l 7
            env:
            - name: AZURE_TENANT_ID
              value: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
            - name: AZURE_CLIENT_ID
              value: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
            - name: AZURE_CLIENT_SECRET
              valueFrom:
                secretKeyRef:
                  name: mySecret
                  key: mySecretKey
          restartPolicy: OnFailure