Openshift roundrobin request across all pods

If you want to access through pod1, pod2, pod3 in order, the you should use leastconn on the same pod group.

leastconn   The server with the lowest number of connections receives the              connection. Round-robin is performed within groups of servers              of the same load to ensure that all servers will be used. Use              of this algorithm is recommended where very long sessions are              expected, such as LDAP, SQL, TSE, etc... but is not very well              suited for protocols using short sessions such as HTTP. This              algorithm is dynamic, which means that server weights may be              adjusted on the fly for slow starts for instance.

roundrobin of HAProxy would distribute the request equally, but it might not protect the accessing server order in the group.

roundrobin  Each server is used in turns, according to their weights.              This is the smoothest and fairest algorithm when the server's              processing time remains equally distributed. This algorithm              is dynamic, which means that server weights may be adjusted              on the fly for slow starts for instance. It is limited by              design to 4095 active servers per backend. Note that in some              large farms, when a server becomes up after having been down              for a very short time, it may sometimes take a few hundreds              requests for it to be re-integrated into the farm and start              receiving traffic. This is normal, though very rare. It is              indicated here in case you would have the chance to observe              it, so that you don't worry.

Refer HAProxy balance (algorithm) for details of balance algorithm options.