Azure Key Vault availability and redundancy
Azure Key Vault features multiple layers of redundancy to make sure that your keys and secrets remain available to your application even if individual components of the service fail.
The contents of your key vault are replicated within the region and to a secondary region at least 150 miles away, but within the same geography to maintain high durability of your keys and secrets. For details about specific region pairs, see Azure paired regions.
If individual components within the key vault service fail, alternate components within the region step in to serve your request to make sure that there is no degradation of functionality. You don't need to take any action to start this process, it happens automatically and will be transparent to you.
In the rare event that an entire Azure region is unavailable, the requests that you make of Azure Key Vault in that region are automatically routed (failed over) to a secondary region except in the case of the China North region. When the primary region is available again, requests are routed back (failed back) to the primary region. Again, you don't need to take any action because this happens automatically.
In the China North and Qatar Central region, you must plan for the recovery of your Azure key vaults in a region failure scenario. To back up and restore your Azure key vault to a region of your choice, complete the steps that are detailed in Azure Key Vault backup.
Through this high availability design, Azure Key Vault requires no downtime for maintenance activities.
There are a few caveats to be aware of:
In the event of a region failover, it may take a few minutes for the service to fail over. Requests made during this time before failover may fail.
If you're using private link to connect to your key vault, it may take up to 20 minutes for the connection to be re-established in the event of a region failover.
During failover, your key vault is in read-only mode. The following operations are supported in read-only mode:
- List certificates
- Get certificates
- List secrets
- Get secrets
- List keys
- Get (properties of) keys
- Encrypt
- Decrypt
- Wrap
- Unwrap
- Verify
- Sign
- Backup
During failover, you won't be able to make changes to key vault properties. You won't be able to change access policy or firewall configurations and settings.
After a failover is failed back, all request types (including read and write requests) are available.