Why Azure Storage and Duplicity?
Azure Storage Accounts are a great place to store your backup files. It’s cheap, as cheap as 10 dolars/month for 1 Terabyte of storage (based on cool tier) plus what you pay to read data out of the Storage Account. Though it may be cheaper to just buy Onedrive storage and use it, but I haven’t tried that option. Duplicity encrypts all the data before sending it to Azure and it has incremental backups which effectively saves some space. Ultimately I decided to go this route because I have an Azure account ready to go and want to use it more.
How to Backup Your Data to Azure Using Duplicity
Automated encrypted backup of your data to an Azure Storage Account.
We’ll be using duplicity to perform the backup: http://duplicity.nongnu.org/
Steps
Prep work
Create a file that will store the passphrase, azure storage key and azure storage account name
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AZURE_ACCOUNT_NAME="yourstorageaccountname"
AZURE_ACCOUNT_KEY="storageaccountkey"
PASSPHRASE="banana123"
Save the file under /root and only allow root itself to read it
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cat > /root/.passphrase << EOF
AZURE_ACCOUNT_NAME="yourstorageaccountname"
AZURE_ACCOUNT_KEY="storageaccountkey"
PASSPHRASE="banana123"
EOF
chmod 700 /root/.passphrase
Azure backend
If you want to use azure as backend you need to have python3 installed and the Microsoft Azure Storage SDK for Python (https://pypi.python.org/pypi/azure-storage/) version 0.36.0 or earlier.
Create cron backup script
We will create a backup script with the following content:
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#!/bin/sh
test -x /usr/bin/duplicity || exit 0
. /root/.passphrase
export PASSPHRASE
export AZURE_ACCOUNT_NAME
export AZURE_ACCOUNT_KEY
/usr/bin/duplicity <source> azure://<container_name> # no subfolders are allowed
unset PASSPHRASE
unset AZURE_ACCOUNT_NAME
unset AZURE_ACCOUNT_KEY
I want to set duplicity to create daily incremental backups.
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cd /etc/cron.daily
cat > duplicity.sh << EOF
#!/bin/sh
test -x /usr/bin/duplicity || exit 0
. /root/.passphrase
export PASSPHRASE
export AZURE_ACCOUNT_NAME
export AZURE_ACCOUNT_KEY
/usr/bin/duplicity <source_folder> azure://container_name # no subfolders are allowed
unset PASSPHRASE
unset AZURE_ACCOUNT_NAME
unset AZURE_ACCOUNT_KEY
EOF
Restoring data
To restore the data is quite straighforward and is basically just reverting the parameters passed to duplicity.
Basically:
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/usr/bin/duplicity azure://container_name <destination_folder>
A full restore script would look something like:
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#!/bin/sh
test -x /usr/bin/duplicity || exit 0
. /root/.passphrase
export PASSPHRASE
export AZURE_ACCOUNT_NAME
export AZURE_ACCOUNT_KEY
/usr/bin/duplicity azure://<container_name> <destination>
unset PASSPHRASE
unset AZURE_ACCOUNT_NAME
unset AZURE_ACCOUNT_KEY