Proposed plan to complete this task:
- Put new storage systems in production with stretch
- Install new systems with stretch (shipment and racking pending, T210498)
- Add hosts to elasticsearch cluster
- Add hosts to kafka cluster
- Take old storage hosts out of service for elasticsearch
- Migrate all ES indices onto new hosts
- Retire ES on old hosts
- Take old storage hosts out of service for kafka
- migrate logstash1004 to logstash1010
- migrate logstash1005 to logstash1011
- migrate logstash1006 to logstash1012
- All producers/consumers pointed to new kafka brokers
- Replace logstash jessie VMs (logstash100[789]) with stretch VMs