Summary

In the same way that in 9.10 we made it possible to install UEC on two servers, we will support a greater variety of configurations, such as those explained in https://help.ubuntu.com/community/UEC/Topologies. This includes updating the installer to support this.

Release Note

The UEC installer now supports installing clouds with a greater variety of topologies, including multiple clusters.

Rationale

This change expands UEC installation support to cover more sophisticated setups, as well as the simple single-cluster setup supported in 9.10. Multi-cluster support is valuable in more complex environments.

Target topologies

example topology

Design

This work builds on the work done in the 9.10 cycle to enable cloud setup in the installer (foundations-karmic-cloud-setup-in-server-installer). That work permitted installation of either a "simple cluster" (CLC+Walrus+CC+SC) or a node. This will operate in much the same way, but with a greater variety of possible target systems.

The installer should perform initial discovery to determine the topology, and should transfer public credentials from the next host up the connection tree so that that host can execute commands on the one currently being installed. Upstart jobs will complete registration at boot time, although that is explicitly out of scope for this specification; see server-lucid-euca-remote-autoregister.

Discovery

We will continue to support Avahi for discovery. However, Avahi or indeed any other similar discovery system only works if broadcasts from the to-be-discovered host are visible on the discovering host. (Avahi does support "reflection" of discovery packets using a special proxy, but we ought not to require excessively complex network setup.) As such, wherever we support Avahi discovery, we will also support manual entry of a hostname or IP address. This is particularly relevant for the cloud controller location, since multiple clusters are particularly liable not to be on the same Avahi broadcast domain.

Who needs to be able to discover whom:

discovery paths

Who needs to be able to connect to whom:

connection paths

Currently, the installer only discovers the CC when installing the NC. We will expand this as follows:

Finally, Avahi publication on the CC tends to have the effect of mistakenly advertising public IP addresses of nodes as well, since the CC does routing for those addresses (458904). We will add an extra TXT record to the advertisement containing the correct IP address.

Test/Demo Plan

It's important that we are able to test new features, and demonstrate them to users. Use this section to describe a short plan that anybody can follow that demonstrates the feature is working. This can then be used during testing, and to show off after release. Please add an entry to http://testcases.qa.ubuntu.com/Coverage/NewFeatures for tracking test coverage.

This need not be added or completed until the specification is nearing beta.

Notes from BoF

Network topology configuration:

(We will continue to offer only MANAGED-NOVLAN.)

Public/private interface selection bug: 455816


CategorySpec

FoundationsTeam/UECInstallerEnhancement (last edited 2009-12-01 18:14:40 by cjwatson)