To create an HA group, complete the following:
- From the Cloud Services Portal, click Manage -> IPAM/DHCP -> HA Groups -> Create HA Group.
- On the Create HA Group page, specify the following:
Name: Enter a name for the HA group.
Description: Enter additional information about the HA group.
SERVICE INSTANCES:
HA Configuration: Select one of the following:
- Active / Active: Both hosts remain active.
- Active / Passive: One host remains active and one remains passive. When the active host is down, the passive host takes over.
Advanced Active / Passive: One host may be a part of multiple HA groups. When the active host is down, the passive host takes over.
Active: Select a host from the column selector. This is the active host.
Port: Displays the port number associated with the respective host.
Active Host / Passive Host: Select a host from the column selector. This is the Active Host if the HA Configuration is Active/Active. This is the Passive Host if the HA Configuration is Active/Passive.
- Switch Active / Passive: Click this button to switch hosts between Active and Passive. On clicking the button, the Active node becomes the Passive node. This feature can be used to initiate a manual failover and for troubleshooting purposes.
Port: Displays the port number associated with the respective host.
- Anycast: In Anycast mode, Anycast is used for configuring HA. Before creating a DHCP HA group by using Anycast, make sure Anycast is configured on the Anycast page; for more information, see Creating Anycast Configuration. DHCP with Anycast can be configured only with two nodes. On the Create HA Group page, select the Anycast configuration available:
- Peer Connections: Configure the peer connections for the Anycast configuration. Peer connection IPs are the addresses over which the users want two hosts in this HA group to communicate. Default values will be the two hosts' primary addresses. You can override them, but make sure that the new values represent the interfaces available on these two hosts.
Destination IP: Specify an IPv4 address.
- Peer Connections: Configure the peer connections for the Anycast configuration. Peer connection IPs are the addresses over which the users want two hosts in this HA group to communicate. Default values will be the two hosts' primary addresses. You can override them, but make sure that the new values represent the interfaces available on these two hosts.
- Tags: For information about tags, see Managing Tags.
Click Save & Close to save the details or click Cancel to exit.
Note
It is highly recommended to configure hosts in such a way that there is no communication failure between them. This is to avoid a situation where both hosts are attempting to serve the same subnet at the same time due to communication failure.
Note
When the active host goes down the active or passive host takes over as per your configuration. However, there may be a short delay in the switchover which may result in a gap in the lease allocation.
Note
If you assign a different host for the Anycast configuration on the Anycast page, you must modify the HA group to use the modified host. If you change the linked protocol in the Anycast configuration on the Anycast page to DNS, you must delete the HA group.
Status Changes in HA Peer
When an HA peer changes status (if a host is down), the status is shown on the Hosts page. Error messages related to issues with the host are also displayed. For more information, see Viewing General Host Information.
Note
It is highly recommended to configure devices in an HA pair with the same time. You can either do it by syncing the devices to an NTP server or updating the time manually, with a difference of no more than 30 seconds. Failing to do so will lead to the HA pair not syncing with each other. In such a scenario, sync the devices and restart the DHCP service. If you see the message This host in HA mode with peer reported: terminated, re-sync the time on the HA peers to an NTP server or update the time manually.
HA groups are not supported for IPv6.