VMware Tanzu TAS for VMS Get "argument list too long" error message when staging an application

Products

• VMware Tanzu Application Service for VMs

Resolution

Checklist:

Application staging with a very large VCAP_SERVICES value could fail with error "argument list too long". 

Staging app and tracing logs...
   Downloading nodejs_buildpack_...
   Downloaded nodejs_buildpack
   Cell 8572a6a2-3e39-480d-8e00-ac04babfa0f2 creating container for instance 55128f58-2dbc-46a4-1233-44958ad0e044
   Cell 8572a6a2-3e39-480d-8e00-ac04babfa0f2 successfully created container for instance 55128f58-2dbc-46a4-1233-44958ad0e044
   Downloading app package...
   Downloaded app package (69M)
   Failed to compile droplet: Failed to run finalize script: fork/exec /tmp/buildpacks/3f36b721bcdd1582488cdc63c9eeaf98/bin/supply: argument list too long

During staging an application, both scripts(supply, detect, finalize, etc) arguments and environment variables are passed to exec to start a new process. There are two limits with the arguments/environment variables length. 

• total length, which is defined by ARG_MAX and can be fetched by `getconf ARG_MAX` it is 2097152. 
• length of a single string, which is defined by MAX_ARG_STRLEN in binfmts.h, it is PAGE_SIZE * 32 = 131072.

Usually the first limit ARG_MAX won't be exceeded. However MAX_ARG_STRLEN could be exceeded if the single app is binding to too many services, which results in VCAP_SERVICES longer than 128KBs (after credhub interpolation). 

The solution is to reduce VCAP_SERVICES length to less than 128KBs.