Having prepared the environment on both SoftNAS on AWS instances, we can now set up high availability. The first step towards high availability in SoftNAS is to establish replication. SnapReplicate™ makes this as simple as completing a quick wizard.
To establish the secure SnapReplicate relationship between two SoftNAS nodes, simply follow the steps given below:
- Log into the source controller's (the first instance within which you created the CIFS enabled volume) SoftNAS StorageCenter administrator interface using a web browser.
- In the Left Navigation Pane, select the SnapReplicate™/SNAP HA™ option.
The SnapReplicate/SNAP HA page will be displayed.
- Click the Add Replication button in the Replication Control Panel.
The Add Replication wizard will be displayed. Read the instructions on the screen and then click the Next button.
In the next step, enter the IP address or DNS name of the remote, target SoftNAS controller node in the Hostname or IP Address text entry box. Note that by specifying the replication target's IP address, you are specifying the network path the SnapReplicate™ traffic will take.
The source node must be able to connect via HTTPS to the target node (similar to how the browser user logs into StorageCenter using HTTPS). HTTPS is used to create the initial SnapReplicate configuration. Next, several SSH sessions are established to ensure two-way communications between the nodes is possible. When connecting two Amazon EC2 nodes, it is best to use the internal instance IP addresses, as traffic is routed internally by default between instances in EC2.
Note: If you have not yet done so, the Security Group on each instance should be configured with the internal IP addresses of the paired instance (the source instance should recognize traffic from the target instance, and the target instance should recognize traffic from the source) to ensure both HTTPS and SSH traffic between instances is recognized. See Configuring Security Groups to learn more.
- Next, provide the username (softnas) and the password (if default, this is the instance id) of the target instance. Type the password again to verify, then click Next.
The IP address/DNS name and login credentials of the target node will be verified. If there is a problem, an error message will be displayed. Click the Previous button to make the necessary corrections and then click the Next button to continue.
- Read the final instructions and then click the Finish button.
The SnapReplicate relationship between the two SoftNAS controller nodes will be established. The corresponding SyncImage of the SnapReplicate will be displayed.
After data from the volumes on the source node is mirrored to the target, once per minute SnapReplicate transfers keep the target node hot with data block changes from the source volumes.
The tasks and an event log will be displayed in the Replication Control Panel section. This indicates that a SnapReplicate relationship is established and that replication should be taking place.
Configuring SNAP HA™
SnapReplicate™ establishes a replication relationship, one that can be manually triggered or scheduled, but is not automated. For true high availability in a failover situation, SNAP HA™ must be configured as well.
To configure SNAP HA™, complete the SNAP HA wizard, beginning by clicking Add SNAP HA™.
Note: Configuration of SnapReplicate™ is a prerequisite to setup of SNAP HA™. If SnapReplicate™ is not configured, the Add SNAP HA™ button will be grayed out.
If you have not yet configured a notification email, the opportunity to provide one will be presented prior to continuing SNAP HA™. Provide an email address for support reports and logs to be sent to, and click OK.
Next, choose the high availability type. Virtual IP is the recommended option, allowing for a more secure configuration. Click Next.
Provide a Virtual IP address, and click Next. This is a human-configured IP address (you choose the IP), and can be any IP address that falls outside the CIDR block of the IP addresses of the two SoftNAS HA paired nodes.
Next, enter your AWS Access Key and Secret Key. This is to allow the wizard to automatically configure the second network interface to carry the HA heartbeat traffic. Click Next.
Click Install to begin the HA installation.
Click Finish once the process completes.
At this point SoftNAS will do all of the heavy lifting that is required to establish HA, without the need for any user intervention. The process may take several minutes. After completion, the High Availability SoftNAS pair has been successfully set up across Availability Zones.