Add a Server to a Cross Site Cluster
From within the Cross Site Cluster management page in the Control Panel, click the 'Manage Servers' link in the ‘Management tools’ section.
Within this page, a form will be displayed to enable you to add an existing server into the cluster, as shown below:
First, select a server to add into the cluster from the list provided.
Next, tick or untick the "Enabled" checkbox. Servers that are disabled will still have the Cross Site Cluster IP addresses added to them (they will be rebooted if its a VPS), these IP addresses will be advertised to the Internet with the default preference. This means that any other enabled servers will receive any traffic for these IP addresses.
When a server is selected, a list of available IP addresses that can be used to monitor the status of the server will be populated in the "Monitor IP" field. We cannot use the IP addresses that are provided with the Cross Site Cluster to monitor the health of the server, so the list will consist of the server's existing IP addresses. The IP address chosen here will be used for any health checks assigned to the cluster.
Please note that even if there are no health checks assigned to the cluster, a "Monitor IP" must be provided.
Once the server has been saved, it will be added to the table above the form. This is described below.
How to Manage Servers
The table at the top of this page displays the current members of this cluster (as shown below):
Fields in the table are described below:
- Name – The name of the server. Links to the server management page.
- Enabled – Indicates that the member is enabled in the cluster.
- Monitor IP – The IP address used to monitor the health of the server
- Status – The last known status of the health checks for this server.
- Green indicates all health checks are passing.
- Red for one or more health checks are failing.
- Grey indicates that the last known status isn’t known - this will the displayed when a server is first added to the cluster.
In the "Actions" field for each server, three buttons will be displayed:
- Disable/Enable - disables or enables the server in the cluster respectively.
- Delete - Removes the server from the cluster, and removes any Cross Site Cluster IP addresses as well. This will require a reboot if the server is a VPS.
Once two or more servers have been added to a cluster, a 'Preferences' section will be displayed at the top of the page. This allows you to configure the order in which servers should receive traffic for each cluster IP address.
In this screenshot, whilst health checks are passing, fostoaa1 will receive all traffic for 188.8.131.52 and fostaa11 will receive all traffic for 184.108.40.206. If health checks for fostoaa1 began to fail, traffic for 220.127.116.11 would then be routed to the next server in the list, which in this instance would be fostoaa11.
Servers that appear in a green box are enabled, whereas red boxes indicate that the server is disabled.
The order in which servers received traffic can be altered by dragging and dropping the boxes into the correct position in the list. Please note that they can only be moved within the column that they are currently in.
It is possible to have two servers or load balancers at the same position in the list, providing that they are in different network zones. This will mean that traffic for that IP address will be distributed between these two servers. In this scenario, the traffic that each server receives will be based on the route taken into our network, and therefore will be unlikely to be shared equally. There are some use cases for this, but in general it is advisable to use an active-active cluster with round-robin DNS to distribute traffic between them.
Last updated 10 October 2017, 09:28 GMT