demo: script to set up vanilla multicluster env

[allenlsy]

Description:

Add a script to set up a demo multicluster environment for OSM development.

It deploys the sample bookstore application on cluster c1 and c2. C2 exports its bookstore service via ServiceExport and c1 imports it via ServiceImport. A new EndpointSlice resource on c1 is created to store accessible endpoint from c2.

The steps listed in the script are:

1. Setup CRDs
2. Deploy applications
3. Create ServiceExport in c2
4. Create ServiceImport in c1. It will have a ClusterSetIP
5. Expose bookstore on c2 and get service public IP
6. On c1, create EndpointSlice containing the remote service IP
7. (optional) update coreDNS entries of domain bookstore.bookstore.svc.clusterset.local

Partially resolves #4974

Testing done:

Script is tested by executing with 2 clusters.

The end result of running the script:

• [c1] Created ServiceImport with MultiClusterService IP
• [c1] Created EndpointSlice with public service IP from c2
• [c2] Created ServiceExport

Affected area:

Functional Area
Demo	[x]

Please answer the following questions with yes/no.

1. Does this change contain code from or inspired by another project?
   • Did you notify the maintainers and provide attribution? No.

The demo is inspired by mcs-api

8. Is this a breaking change?

No

9. Has documentation corresponding to this change been updated in the osm-docs repo (if applicable)?

No

[codecov-commenter]

Codecov Report

Merging #4985 (e306ac1) into main (39b7ad5) will increase coverage by 0.33%. The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #4985      +/-   ##
==========================================
+ Coverage   68.40%   68.74%   +0.33%     
==========================================
  Files         218      217       -1     
  Lines       15844    15849       +5     
==========================================
+ Hits        10838    10895      +57     
+ Misses       4951     4897      -54     
- Partials       55       57       +2     

Flag	Coverage Δ
unittests	68.74% <ø> (+0.33%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pkg/debugger/mock_debugger_generated.go	67.74% <0.00%> (-10.04%)	:arrow_down:
pkg/certificate/certificate.go	90.24% <0.00%> (-4.63%)	:arrow_down:
pkg/debugger/certificate.go	85.71% <0.00%> (-3.76%)	:arrow_down:
pkg/utils/mtls.go	100.00% <0.00%> (ø)
pkg/debugger/server.go	100.00% <0.00%> (ø)
pkg/k8s/events/types.go	72.34% <0.00%> (ø)
pkg/envoy/eds/cluster_load_assignment.go
pkg/smi/health.go
pkg/envoy/eds/builder.go	76.92% <0.00%> (ø)
cmd/osm-controller/osm-controller.go	16.94% <0.00%> (+0.14%)	:arrow_up:
... and 6 more

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[allenlsy]

FYI I executed the script with c1 and c2 deployed on same subnet without OSM installed, c1 bookbuyer cannot access c2 bookstore by ClusterIP. But c1 bookbuyer can access c2 bookstore by:

• c2 bookstore endpoint's pod IP
• OR c2 bookstore external IP (if exposed)

With OSM installed, c1 cannot access c2 services due to failed mTLS authn.

[jsturtevant]

With OSM installed, c1 cannot access c2 services due to failed mTLS authn.

Is it possible to make them talk with OSM installed?

Maybe a readme could be helpful for things like: what the configuration of the two clusters was (kind/aks) and was there additional components installed (Submariner)?