we have several processes (~20) which are shared among all tenants.
Unfortunatly we have a very large amount of tenants (at least 400)
How can I start a process via the REST API with providing the Tenant-Id the process is running for?
Because when providing the tenant id (tenant-xyz) in the URL path (/process-definition/key/sample-proc/tenant-id/tenant-xyz/start) the REST service answers that it cannot find a process definition for this combination of process-key and tenant.
Can I start the process without tenant info and attach the tenant later on via REST? I saw something like TenantIdProvider but how can I use this when I only have a REST client?
If you deploy every process for the each tenant, then only you can query for processinstance/task against the specific tenant. probably you can create a batch job which will deploy all the processes for all the tenants. it will reduce your deployment time
or else you can configure it in processes.xml file so it will auto deploy while application startup itself.
If you dont want to deploy the process for every tenant, then you can deploy only once each process, in this case you cant use the rest api like this (/process-definition/key/sample-proc/tenant-id/tenant-xyz/start). In this u can associate process variable for tenant, and you can query for a process variable which has tenant. its like filter API. You can refer camunda docs for filtering variables.