ECS 2.1 – Plan an installation
Table of Contents
Review the Site Preparation Guide to learn about the environmental requirements associated with the 40U-D cabinet used by the ECS Appliance.Back to Top
An ECS appliance deployment consists of the following components:
- One or more racks.
The rack must be up linked to the customer network for both data traffic and remote management.
The rack and all nodes must be powered on.
The nodes must have valid IP addresses assigned by DHCP or configured statically .
- Infrastructure requirements: The data center environment must include the following servers that are reachable from all nodes.
- DHCP server (if you are assigning IP addresses via DHCP)
- DNS server (or forwarder)
- NTP server
- SMTP server
SSH must be enabled on all nodes.
The following ports are opened and used by the installer:
- Docker registry: 5000
- Lifecycle agent: 9240
- Object: 9020-9025,9040,9091,9094-9098,8088,9898,1095,1096,1098,9100,9101,9111,3218
- ZooKeeper: 9277,9278,9279
See the Security Guide for the list of ports that must be open.Back to Top
The ECS appliance management networks are connected together through the Nile Area Network. The NAN is created by connecting either port 51 or 52 to another turtle switch of another ECS appliance. Through these connections nodes from any segment can communicate to any other node in the NAN.
The simplest topology to connect the ECS appliances together does not require extra switch hardware. All the turtle switches can be connected together a linear or daisy chain fashion.
In this topology, if there is a loss of connectivity a split-brain can occur.
For a more reliable network, the ends of the daisy chain topology can be connected together to create a ring network. The ring topology is more stable because it would require two cable link breaks in the topology for a split-brain to occur. The primary drawback to the ring topology is that the RMM ports cannot be connected to the customer network unless an external customer or aggregation switch is added to ring.
The daisy-chain or ring topologies are not recommended for large installations. When there are four or more ECS appliances, an aggregation switch is recommended. The addition of an aggregation switch in a star topology can provide better fail over by reducing split-brain issues.Back to Top
When planning for a multi-site ECS installation, ensure these requirements are met:
- A minimum of two VDCs is required.
- Each VDC in the multi-site configuration requires IP connectivity to the other VDCs.
- Network latency: Ensure a maximum latency of 1000 ms between sites.
- Free storage: If your disaster plan includes running for a period of time with one site permanently failed (instead of promptly recovering the site), each site needs enough free storage across all sites to accommodate data rebalancing. Across all sites, the amount of free space left should be, in total:
free space across n sites =1.33*x/(n-1)/(n-2)
where x is the total amount of user data across all n sites.
This amount of free space is not required if you add a new site soon after the fail over, and do not continue to operate with (N-1) sites indefinitely.