Which three statements are true about the default behavior of WebLogic Server proxy plug-ins?
A.
The proxy will pin a client to a specific server if a session cookie is created.
B.
The proxy fails over to another server if a connection or request times out.
C.
The proxy distributes requests to cluster members based on their CPU usage.
D.
The proxy dynamically learns the latest locations of cluster members.
E.
The proxy always uses SSL, regardless of the client’s protocol.
F.
The proxy replicates session data to its backup proxy.
Explanation:
A: When the HTTP client requests the servlet, HttpClusterServlet proxies the
request to the WebLogic Server cluster. HttpClusterServlet maintains the list of all servers in the
cluster, and the load balancing logic to use when accessing the cluster. In the above example,
HttpClusterServlet routes the client request to the servlet hosted on WebLogic Server A.
WebLogic Server A becomes the primary server hosting the client’s servlet session.
To provide failover services for the servlet, the primary server replicates the client’s servlet session
state to a secondary WebLogic Server in the cluster. This ensures that a replica of the session
state exists even if the primary server fails (for example, due to a network failure). In the example
above, Server B is selected as the secondary.
The servlet page is returned to the client through the HttpClusterServlet, and the client browser is
instructed to write a cookie that lists the primary and secondary locations of the servlet session
state. If the client browser does not support cookies, WebLogic Server can use URL rewriting
instead.
Figure, Accessing Servlets and JSPs using a Proxy:B: In clusters that utilize Web servers with WebLogic proxy plug-ins, the proxy plug-in handles
failover transparently to the client. If a server fails, the plug-in locates the replicated HTTP session
state on a secondary server and redirects the client’s request accordingly.
D: The WebLogic proxy plug-in maintains a list of WebLogic Server instances that host a clustered
servlet or JSP, and forwards HTTP requests to those instances on a round-robin basis.
Reference: Using WebLogic Server Clusters, Failover and Replication in a Cluster
Reference: Using WebLogic Server Clusters, Load Balancing in a Cluster
