Preparing the cluster for High Availability:
Review the table to understand the requirements for enabling the High Availability.
- This process has been tested with a minimum of five ECS hosts. However, Cloudera recommends six or more hosts.
- DNS requirements for ECS High Availability must be fulfilled.
|Hostname||Subdomain||Expected Roles||DNS ForwardZone||Reverse Zone PTR|
|“Wildcard” (hostname = *)||apps.ecs.example.com The string “apps” is required, “ecs” is up to user||Virtual app domain wildcard||“A Record” wildcard (hostname = *), may be a CNAME on certain DNS systems that use text-based config. Resolves to fixed IP of ha_proxy (or VIP of some commerical LB’s)||N|
|“apps alias”||apps.ecs.example.com||Virtual app domain alias||“CNAME” alias points to A Record of ha_proxy (or VIP). Alternatively, this can be an ARecord with IP of ha_proxy (or VIP)||N/A|
|HAProxy (or commercial LB)||<domain of your LB>||HA Load Balancer||Depends on vendor/software|
|ecs-master1||example.com||ECS Server 1 Docker server||“A Record” resolves to IP of ecs-master1||Y|
|ecs-master2||example.com||ECS Server 2 Docker server||“A Record” resolves to IP of ecs-master2||Y|
|ecs-master3||example.com||ECS Server 3 Docker server||“ARecord” resolves to IP of ecs-master3||Y|
|ecs-agentN||example.com||ECS Agent N Docker server N||“ARecord” resolves to IP of ecs-agentN||Y|