In a deployment with HADR, there are
multiple Liberty servers that host the i2 Analyze
application. To enable analysts to connect to the
deployment by using a single URI, you must use a
load balancer to route requests to each Liberty
server in your deployment.
About this task
For a load balancer to work successfully with
i2 Analyze, it must be configured to:
- Handle WebSocket requests.
- Route requests to the i2 Analyze application
on active Liberty servers only.
- Use a cookie issued by the load balancer to
achieve server persistence for a user. The server
persistence should last as long as possible or
until the server is not active.
If the connection from the clients is secured
by using SSL, you might need to implement SSL
termination in the load balancer to achieve server
persistence.
You can also configure your load balancer to
balance requests across the Liberty servers in
your deployment. The mechanism that you choose
must allow for server persistence to be
maintained.
For more information about load balancers and
application layer server persistence, see Load Balancing,
Affinity, Persistence, Sticky Sessions: What You
Need to Know.
Procedure
- Install your load balancer on a
separate server from any other component in the
deployment.
- Configure your load balancer to
identify the active Liberty servers by using the
api/v1/health/live REST endpoint.
The
live endpoint
returns
200 when the server is
live and processing requests. For more information
about the endpoint, see
The
health/live
endpoint.
Call the live
endpoint on each Liberty server in your
deployment. The endpoint returns the status of a
single Liberty server, and not the others in the
deployment.
- Configure your load balancer to use
cookie-based server persistence.
When a
user connects, if there is no cookie from the load
balancer that indicates it has already connected
to one of the active Liberty servers, provide it
with one. When this user connects again, the
cookie it received ensures that any requests are
routed to the same Liberty server.
If the server
that a user has persistence with is offline, the
load balancer must route the request to a live
Liberty server. The user's cookie must be updated
to achieve persistence with the live server that
it connected to.
- Before you
can connect to i2 Analyze via the load balancer,
you might need to specify the connection URI that
clients can use to connect to i2
Analyze.
- In the
configuration\fragments\opal-services\WEB-INF\classes\DiscoClientSettings.properties
file, set the value of the
FrontEndURI setting to the URI
that can be used to connect to your deployment of
i2 Analyze.
Some load balancers modify
the HTTP origin header, the value that you specify
for the FrontEndURI must match
the value of the HTTP origin header after it is
modified by the load balancer.
What to do next
Continue configuring the i2 Analyze
configuration. For more information, see Deploying i2 Analyze with high availability.
