A number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.
Endpoint Overrides
GOOGLE_CLOUD_CPP_VM_MIGRATION_ENDPOINT=... overrides the EndpointOption (which defaults to "vmmigration.googleapis.com") used by MakeVmMigrationConnection().
GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also set GOOGLE_CLOUD_CPP_ENABLE_CLOG to produce any output on the program's console.
See Also
google::cloud::LoggingComponentsOptionGOOGLE_CLOUD_CPP_TRACING_OPTIONS=...: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.
See Also
google::cloud::GrpcTracingOptionsOptionGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes: turns on logging in the library, basically the library always "logs" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Missing the information I need","missingTheInformationINeed","thumb-down"],["Too complicated / too many steps","tooComplicatedTooManySteps","thumb-down"],["Out of date","outOfDate","thumb-down"],["Samples / code issue","samplesCodeIssue","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-14 UTC."],[[["\u003cp\u003eThis document provides version-specific documentation for the VM Migration C++ library, ranging from version 2.11.0 up to the latest release candidate 2.37.0-rc.\u003c/p\u003e\n"],["\u003cp\u003eEnvironment variables like \u003ccode\u003eGOOGLE_CLOUD_CPP_VM_MIGRATION_ENDPOINT\u003c/code\u003e can be used to configure library behavior, such as overriding the default endpoint used by \u003ccode\u003eMakeVmMigrationConnection()\u003c/code\u003e.\u003c/p\u003e\n"],["\u003cp\u003eTracing for gRPC calls can be enabled using \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc\u003c/code\u003e, which also benefits from setting \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG\u003c/code\u003e to view the output, and \u003ccode\u003eGOOGLE_CLOUD_CPP_TRACING_OPTIONS\u003c/code\u003e can modify how tracing information is displayed.\u003c/p\u003e\n"],["\u003cp\u003eLogging in the library can be turned on with \u003ccode\u003eGOOGLE_CLOUD_CPP_ENABLE_CLOG=yes\u003c/code\u003e, allowing the output of logs to the program's console, whereas the project variable \u003ccode\u003eGOOGLE_CLOUD_PROJECT\u003c/code\u003e is not read by the library and is only used for example usage.\u003c/p\u003e\n"]]],[],null,["Version 2.32.0keyboard_arrow_down\n\n- [2.42.0-rc (latest)](/cpp/docs/reference/vmmigration/latest/vmmigration-env)\n- [2.41.0](/cpp/docs/reference/vmmigration/2.41.0/vmmigration-env)\n- [2.40.0](/cpp/docs/reference/vmmigration/2.40.0/vmmigration-env)\n- [2.39.0](/cpp/docs/reference/vmmigration/2.39.0/vmmigration-env)\n- [2.38.0](/cpp/docs/reference/vmmigration/2.38.0/vmmigration-env)\n- [2.37.0](/cpp/docs/reference/vmmigration/2.37.0/vmmigration-env)\n- [2.36.0](/cpp/docs/reference/vmmigration/2.36.0/vmmigration-env)\n- [2.35.0](/cpp/docs/reference/vmmigration/2.35.0/vmmigration-env)\n- [2.34.0](/cpp/docs/reference/vmmigration/2.34.0/vmmigration-env)\n- [2.33.0](/cpp/docs/reference/vmmigration/2.33.0/vmmigration-env)\n- [2.32.0](/cpp/docs/reference/vmmigration/2.32.0/vmmigration-env)\n- [2.31.0](/cpp/docs/reference/vmmigration/2.31.0/vmmigration-env)\n- [2.30.0](/cpp/docs/reference/vmmigration/2.30.0/vmmigration-env)\n- [2.29.0](/cpp/docs/reference/vmmigration/2.29.0/vmmigration-env)\n- [2.28.0](/cpp/docs/reference/vmmigration/2.28.0/vmmigration-env)\n- [2.27.0](/cpp/docs/reference/vmmigration/2.27.0/vmmigration-env)\n- [2.26.0](/cpp/docs/reference/vmmigration/2.26.0/vmmigration-env)\n- [2.25.1](/cpp/docs/reference/vmmigration/2.25.1/vmmigration-env)\n- [2.24.0](/cpp/docs/reference/vmmigration/2.24.0/vmmigration-env)\n- [2.23.0](/cpp/docs/reference/vmmigration/2.23.0/vmmigration-env)\n- [2.22.1](/cpp/docs/reference/vmmigration/2.22.1/vmmigration-env)\n- [2.21.0](/cpp/docs/reference/vmmigration/2.21.0/vmmigration-env)\n- [2.20.0](/cpp/docs/reference/vmmigration/2.20.0/vmmigration-env)\n- [2.19.0](/cpp/docs/reference/vmmigration/2.19.0/vmmigration-env)\n- [2.18.0](/cpp/docs/reference/vmmigration/2.18.0/vmmigration-env)\n- [2.17.0](/cpp/docs/reference/vmmigration/2.17.0/vmmigration-env)\n- [2.16.0](/cpp/docs/reference/vmmigration/2.16.0/vmmigration-env)\n- [2.15.1](/cpp/docs/reference/vmmigration/2.15.1/vmmigration-env)\n- [2.14.0](/cpp/docs/reference/vmmigration/2.14.0/vmmigration-env)\n- [2.13.0](/cpp/docs/reference/vmmigration/2.13.0/vmmigration-env)\n- [2.12.0](/cpp/docs/reference/vmmigration/2.12.0/vmmigration-env)\n- [2.11.0](/cpp/docs/reference/vmmigration/2.11.0/vmmigration-env) \n\nEnvironment Variables\n=====================\n\nA number of environment variables can be used to configure the behavior of the library. There are also functions to configure this behavior in code. The environment variables are convenient when troubleshooting problems.\n\nEndpoint Overrides\n------------------\n\n- `GOOGLE_CLOUD_CPP_VM_MIGRATION_ENDPOINT=...` overrides the `EndpointOption` (which defaults to \"vmmigration.googleapis.com\") used by `MakeVmMigrationConnection()`.\n\n###### See Also\n\n[`google::cloud::EndpointOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1EndpointOption.html)\n\nLogging\n-------\n\n`GOOGLE_CLOUD_CPP_ENABLE_TRACING=rpc`: turns on tracing for most gRPC calls. The library injects an additional Stub decorator that prints each gRPC request and response. Unless you have configured your own logging backend, you should also set `GOOGLE_CLOUD_CPP_ENABLE_CLOG` to produce any output on the program's console.\n\n###### See Also\n\n[`google::cloud::LoggingComponentsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1LoggingComponentsOption.html)`GOOGLE_CLOUD_CPP_TRACING_OPTIONS=...`: modifies the behavior of gRPC tracing, including whether messages will be output on multiple lines, or whether string/bytes fields will be truncated.\n\n###### See Also\n\n[`google::cloud::GrpcTracingOptionsOption`](https://cloud.google.com/cpp/docs/reference/common/latest/structgoogle_1_1cloud_1_1GrpcTracingOptionsOption.html)`GOOGLE_CLOUD_CPP_ENABLE_CLOG=yes`: turns on logging in the library, basically the library always \"logs\" but the logging infrastructure has no backend to actually print anything until the application sets a backend or they set this environment variable.\n\n###### See Also\n\n[`google::cloud::LogBackend`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogBackend.html)\n\n###### See Also\n\n[`google::cloud::LogSink`](https://cloud.google.com/cpp/docs/reference/common/latest/classgoogle_1_1cloud_1_1LogSink.html)\n\nSetting the Default Project\n---------------------------\n\n`GOOGLE_CLOUD_PROJECT=...`: is used in examples and integration tests to configure the GCP project. This has no effect in the library."]]
