The dynamic name of InstanceName doesn't work when using SwitchOnRebuild

[perosb]

The CM spec uses a dynamic name for "InstanceName".

When using SwitchOnRebuild, CM stores active/rebuild collection in Properties table with the InstanceName as part of the KEY.
Since the name is different for k8s deployments/restarts, the key changes hence it cannot find any references and uses the default index instead of the currently active collection.

Support ticket CS0215027

This is the same issue we found in 9.0 when using PaaS deployments and slots. In that case it was partially solved using a "index-catalogue" (which has other issues tho).

Since the default k8s spec setup only uses a single CM instance it might work with "InstanceName: cm"? (We use multiple CMs and need to named them explicitly)

The same is true for the docker-compose that leaves this empty which uses the container hostname. This of course only applies if running with SwitchOnRebuild.

[jbluemink]

The SwitchOnRebuild seems to work well with SolrCloud, that use alias, and switches the alias, no need to use the Properties database tabel.

https://doc.sitecore.com/xp/en/developers/102/platform-administration-and-architecture/switch-solr-indexes.html

The documentation now also say
Only one Sitecore instance can use the SwitchOnRebuildSolrCloudSearchIndex index type for a particular search index. All other Sitecore instances must use the SolrSearchIndex type, and also use the main alias as the core parameter:

How to configure that with multiple CM is not documented there that, looks nasty for me to do