Hello @BG01
In a dual-site Red Hat OpenShift environment with Cisco ACI (Application Centric Infrastructure), ensuring a smooth switchover from the primary site (DC) to the disaster recovery site (DR) when the primary site fails involves careful planning and configuration. Here's how the process works and how to ensure the same IP addresses are used during the switchover:
1. Cisco ACI Multi-Site Architecture
- Cisco ACI supports a multi-site architecture where multiple ACI fabrics (e.g., DC and DR) are interconnected using the ACI Multi-Site Orchestrator (MSO).
- MSO allows you to define consistent network policies, including EPGs (Endpoint Groups), contracts, and subnets, across multiple sites.
- The key to ensuring the same IP addresses are used in both sites is to configure the same bridge domains (BDs) and subnets in both DC and DR fabrics.
2. IP Address Consistency
- In ACI, IP addresses are typically assigned within a bridge domain (BD) that is associated with a subnet.
- To ensure the same IP addresses are used during a switchover, the same BD and subnet configuration must exist in both the DC and DR sites.
- MSO can help synchronize these configurations across sites.
3. OpenShift Configuration
- OpenShift nodes and pods rely on the underlying network for IP address assignment.
- Ensure that the OpenShift cluster in the DR site is configured to use the same network policies and IP ranges as the primary site.
- This can be achieved by replicating the OpenShift network configuration (e.g., SDN or CNI plugin settings) between the two sites.
4. Switchover Process
- When the primary site fails, the following steps are typically involved in the switchover process:
- Failover Detection: Detect the failure of the primary site. This can be automated using monitoring tools or manual intervention.
- Activate DR Site: Bring up the OpenShift cluster in the DR site. This may involve starting VMs, containers, or other resources that were in standby mode.
- Network Reconfiguration: Ensure that the DR site takes over the IP addresses and routing previously handled by the primary site. This is where ACI's multi-site capabilities are critical.
- DNS Update: Update DNS records to point to the DR site for any services that were hosted in the primary site.
- Application Recovery: Restore applications and workloads in the DR site using backups, replication, or other recovery mechanisms.
5. ACI Multi-Site Configuration
- To ensure seamless IP address usage, configure the following in ACI:
- Shared Bridge Domains: Use the same BD and subnet configuration in both DC and DR sites. This ensures that endpoints (e.g., OpenShift nodes and pods) can use the same IP addresses in both sites.
- L3Out Configuration: Configure Layer 3 Out (L3Out) connections in both sites to advertise the same subnets to the external network.
- Policy Replication: Use MSO to replicate ACI policies (e.g., EPGs, contracts) across sites.
6. Data Synchronization
- Ensure that application data and state are synchronized between the DC and DR sites. This can be achieved using storage replication, database replication, or other data synchronization mechanisms.
7. Testing and Validation
- Regularly test the switchover process to ensure that it works as expected. This includes verifying that the same IP addresses are used and that applications function correctly in the DR site.
By leveraging Cisco ACI's multi-site capabilities and carefully configuring both the ACI and OpenShift environments, you can ensure that the same IP addresses are used during a switchover, minimizing disruption to applications and services.
Hope This Helps!!!
AshSe
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